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Think you had a bad day at work? At least you didn't lose equipment worth hundreds of millions of dollars (at least, I'm assuming you didn't). Forgetting to convert units can result in big-time disasters like these six examples.

1. Can you imagine losing $125 million thanks to a little metric system error? That's exactly what happened in 1999 when NASA lost a Mars orbiter because one team used metric units for a calculation and the other team didn't. Guess they didn't learn from their previous mistake...

2. ... just the year before, NASA lost equipment worth millions thanks to shoddy conversion practices. SOHO, the Solar Heliospheric Observatory, a joint project between NASA and the ESA (European Space Agency), lost all communications with Earth. After about a week of trying various things, communication was restored and everyone breathed a sigh of relief. Among the problems thought to have caused the sudden blackout?

* There was an error in the spacecraft's navigation measurements of nearly 100 km, which resulted in a much lower altitude than expected and led to the vehicle's break-up in the atmosphere.
* The conversion factor from English to Metric units was erroneously left out of the AMD files.
* Interface Specification required that the impulse-bit calculations should be done using Metric Units.

3. In 1983, an Air Canada plane ran out of fuel in the middle of a flight. The cause? Not one but two mistakes in figuring how much fuel was needed. It was Air Canada's first plane to use metric measurements and clearly not everyone had the hang of it yet. Luckily, no one was killed and only two people received minor injuries. That's amazing considering the flight crew thought they had double the fuel they actually had.

4. In 1999, the Institute for Safe Medication Practices reported an instance where a patient had received 0.5 grams of Phenobarbital (a sedative) instead of 0.5 grains when the recommendation was misread. A grain is a unit of measure equal to about 0.065 grams... yikes. The Institute emphasized that only the metric system should be used for prescribing drugs.

5. An aircraft more than 30,000 pounds overweight is certainly no laughing matter. In 1994, the FAA received an anonymous tip that an American International Airways (now Kalitta Air, a cargo airline) flight had landed 15 tons heavier than it should have. The FAA investigated and discovered that the problem was in a kilogram-to-pounds conversion (or lack thereof).

6. Even Columbus had conversion problems. He miscalculated the circumference of the earth when he used Roman miles instead of nautical miles, which is part of the reason he unexpectedly ended up in the Bahamas on October 12, 1492, and assumed he had hit Asia. Whoops.

Do any more unit conversion disasters spring to mind? Ever had one yourself? Tell us all about it in the comments.

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The Quick 6: Six Unit Conversion Disasters

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Think you had a bad day at work? At least you didn't lose equipment worth hundreds of millions of dollars (at least, I'm assuming you didn't). Forgetting to convert units can result in big-time disasters like these six examples. 1. Can you imagine losing $125 million thanks to a little metric system error?

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How Does Radiocarbon Dating Work? - Instant Egghead #28

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Seconds From Disaster - Meltdown at Chernobyl - FULL - NuclearAdvisor.com

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The Chernobyl disaster (Ukrainian: Чорнобильська катастрофа, Chornobylska Katastrofa -- Chornobyl Catastrophe) was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine (then officially Ukrainian SSR), which was under the direct jurisdiction of the central authorities of the Soviet Union.

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What is radiation? Are all types harmful? What are the most common sources of damaging radiation? Most people view radiation as harmful and negative without understanding what makes it potentially damaging and which forms should be avoided. For example, many felt radiation from mobile phones probably caused cancer but few focused on the carcinogenic effects of UV rays.

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An AUS-e-TUTE animation, not a lecture, on the technique of ascending paper chromatography suitable for High School Chemistry students. Get the complete tutorial, including games, tests, exams, drills, worksheets, quizzes and interactive leaning activities at http://www.ausetute.com.au

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Ocean Acidification by the Alliance for Climate Education

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In an interview Wednesday, Mr. Howe explained that it was important to determine whether the worms - which are the larval form of the greater wax moth and are commercially bred to be used by fishermen - were actually breaking chemical bonds in the plastic, and not just chewing the material down into smaller pieces.

To answer the question, the researchers employed what Mr. Howe delicately referred to as a "homogenated worm." The scientists ground the larvae in a blender and spread the resulting paste on the plastic. That showed that it was some chemical or combination of chemicals within the insects that was causing the plastic to degrade.

"We think that it's some enzyme that's involved," Mr. Howe said. "We don't know if it's actually produced by the worms or actually is produced by bacteria in the gut of the worms."

That mystery enzyme or enzymes is breaking the long chain of carbon atoms at the center of the plastic into smaller containing molecules, Mr. Howe said. And while the researchers are not yet sure what those smaller molecules are, it is likely that they will be easier to recycle and reuse than the plastic from which they came.

Next, the scientists will begin to isolate individual elements within extracts from the worms, in an attempt to narrow down the chemical breaking the plastic's bonds. If they are able to isolate that enzyme, then it might be possible to obtain the gene governing it and to insert that gene into a bacteria, which could be easier than cultivating the worms. Eventually, that bacteria could be used as the basis of a biotechnology process, Mr. Howe said.

He cautioned, however, that it would be at least several years before the initial discovery could lead to such a result.

"It's certainly not going to be the case that within six months we've solved the world's plastic problem," he said. "I certainly wouldn't want your readers to think that within a few months, they can start throwing away plastic bags without worrying about it."

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A Very Hungry Caterpillar Eats Plastic Bags, Researchers Say

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In an interview Wednesday, Mr. Howe explained that it was important to determine whether the worms - which are the larval form of the greater wax moth and are commercially bred to be used by fishermen - were actually breaking chemical bonds in the plastic, and not just chewing the material down into smaller pieces.

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The threat of invasive species - Jennifer Klos

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In the UK, much of northern Europe and parts of North America, lurks an organism which causes catastrophic ecological damage....no it's not humans, although we do fit that description, it's a plant that hails from the highest mountain range in the world. This week David explores the explosive world of the invasive Himalayan balsam.

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How do they do that?

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Boats and boating--Equipment and supplies

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Murmuration (Official Video) by Sophie Windsor Clive & Liberty Smith

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This video was produced by Julia Malleck, Andrew Jefferies and Jack Colelli at Tufts University as part of the undergraduate research and media project in Environmental Biology (Bio 7) during the Fall 2015 semester. Opinions expressed in this video are of the students and do not necessarily reflect the opinions of the Environmental Studies Program or Tufts University.

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Basking shark, Canada's largest fish, used to be bountiful until we tried to wipe them out

Lisa Johnson - CBC News

June 06, 2016

An image of the first confirmed sighting of a basking shark in B.C. this year, taken by researchers on CCGS Vector on the Central Coast. (Fisheries and Oceans Canada)

It's the kind of call from work you can actually be excited about early on a Sunday morning - if you're a research scientist with Fisheries and Oceans Canada, that is.

Basking sharks are named for their practice of 'basking' near the surface of the water, mouth open to capture zooplankton for food. (Greg Skomal/NOAA)

At 8 a.m. PT on May 29, Jackie King picked up the phone to the elated voices of her colleagues onboard the CCGS Vector, a science vessel patrolling B.C.'s Central Coast.

"I can't believe they see a basking shark and I'm talking to them right now," said King, recalling her thoughts that morning. "It was a lot of excitement for sure."

King herself has never seen a basking shark, but says she's dreamed of it.

The endangered shark is the size of a bus, the largest fish in Canadian waters and used to hang out in groups of 100 or more off the B.C. coast.

But they're now so rare - thanks to a federal eradication program and commercial fishery decades ago - that the couple of sightings in Canada each year is cause for celebration for those who hope these gentle giants can come back.

Sliced in half on purpose

The Pacific population of basking sharks were listed as endangered in Canada in 2010, but "virtually disappeared" from B.C. waters years before that.

And that was on purpose.

An illustration from Popular Mechanics in 1956 shows the equipment used in the federal government's program to eradicate basking sharks on the B.C. coast: a special blade on the bow of a boat, to slice them in half. (Popular Mechanics via The Marine Detective)

"They were considered by commercial fishermen to be a bit of a nuisance because they would get entangled in nets," said King.

They were officially deemed "Destructive Pests" by the federal fisheries department in 1949, as Scott Wallace and Brian Gisborne document in the book Basking Sharks: The Slaughter of B.C.'s Gentle Giants.

In 1955, the federal government began a 14-year eradication program, which included a specially-commissioned vessel equipped with a blade on the bow, to ram the sharks and slice them in two.

"The sharks, floating lazily near the surface of the water, are no match for the skillfully handled vessel [with its] sharp point and keen upper cutting edge," wrote Popular Mechanics about the blade in 1956.

The sharks were also commercially fished for liver oil and died in fishermen's nets.

Huge fish, tiny prey

It was obvious to excited fisheries researchers last week they had spotted one of these sought-after basking sharks, but it might be trickier for the untrained eye.

"They will most likely be this large animal that you can't quite tell, is that actually a shark?" said King.

The first clue is their size. Basking sharks are "exceptionally large," said King. They're the second-largest fish in the world usually reaching nine metres long, with reports of some reaching 12 metres.

They're generally spotted "basking" near the surface, cruising for the tiny zooplankton that makes up their main food source, with a dorsal (back) fin that may reach one metre out of the water.

Two more views of the large dorsal fin of the basking shark spotted by researchers May 29 on the B.C. Central Coast. (Fisheries and Oceans Canada)

"It's going to have its mouth wide open filtering, [that] gives it this really weird look," said King.

"People typically think of sharks as being voracious predators, but these are really gentle giants that feed by filtering out the water at the surface and eating tiny little plankton."

Shark hotline

Eight years ago, Fisheries and Oceans Canada established a shark hotline at 1-877-50-SHARK to gather information from fishermen and anyone else on the water who might spot a basking shark.

There's also an online form to submit photos, something King says they receive surprisingly few of - given the ubiquity of smartphone cameras.

So, if you see something big and "weird," with a large shark-like fin, King wants to know about it.

"It's pretty special to get to see a basking shark in our waters."

Basking sharks are very large and use their gaping mouths to feed on tiny plankton at the surface of the water, as seen in this undated photo with human divers. (Chris Gotschalk)

ABOUT THE AUTHOR

Lisa Johnson is a reporter for CBC News in Vancouver, covering news around the province with a specialty in science, nature, and making sense of complicated things. Before becoming a journalist she pipetted DNA and watched fish mating dances en route to a degree in evolutionary ecology.

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Sighting of rare giant basking shark in B.C. thrills scientists

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Lisa Johnson - CBC News June 06, 2016 It's the kind of call from work you can actually be excited about early on a Sunday morning - if you're a research scientist with Fisheries and Oceans Canada, that is. At 8 a.m.

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In 1991, arborist David Milarch had a near-death experience that inspired a personal quest to reforest our planet. He would harvest the genetics of the world's oldest trees, initiate tree-planting efforts to combat climate change, and help restore the planet's health. Remarkably, he has been doing just that.

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In 2003, I was told by a restaurant owner on a Thai island that local fishermen used to wrap their lunch in banana leaves, which they would then casually toss overboard when done. That was OK, because the leaves decayed and the fish ate the scraps. But in the past decade, he said, while plastic wrap had rapidly replaced banana leaves, old habits had died hard - and that was why the beach was fringed with a crust of plastic. Beyond the merely unsightly, this plastic congregates in continent-scale garbage gyres in our oceans, being eaten by plankton, then fish; then quite possibly it'll reach your plate ...

This is a worldwide problem - we can't point the finger at Thai fishermen. The west started this. The developing world justifiably yearns for its living standards and, with it, its unsustainable convenience culture.

The UK alone produces more than 170m tonnes of waste every year, much of it food packaging. While it has revolutionised the way we store and consume food, there is now so much of it that landfills can't cope. Some of it is poisonous, and some of it never degrades. It can take 450 years for some types of plastic bottle to break down; one type, PET, while recyclable, doesn't biodegrade at all. And yet only a third of plastic packaging is recycled. Indeed, as Rachelle Strauss of the UK's ZeroWasteWeek, says, we never actually throw anything "away" - it's really just put somewhere else.

But recycling is just a drop in the ocean - most of the environmental cost of our throwaway wrapping is upstream - in its manufacture. We were closer to an answer 30 years ago: what on earth happened to milkmen and bottle deposits? Now we live in an absurd age where a packet of crisps can have seven layers of wrapping.

It's easy to despair at the scale of the task, but it isn't beyond humanity to solve it - look at how the world took action on CFCs: there are signs that the hole in the ozone layer is now closing. Food packaging ought to be a doddle.

Manufacturers got us into this mess, and our governments must take responsibility. But will they? There are some signs the ship is creaking toward a better course: the words Reduce Reuse Recycle have been on conscious consumers' lips for decades; recycling is now commonplace, and there are newer initiatives like the plastic bag charge. We'd also do well to follow France's lead in banning plastic cutlery, cups and plates.

As consumers, we can vote with our feet and our wallets. Even a cursory inspection online reveals a heap of solutions for the canny shopper, from biopackaging for sandwiches and London Bio Packaging. and water-soluble paper to refill schemes becoming available on the high street.

So, we asked readers how they tackle the packaging problem. Many suggested we should create less waste to begin with - as so many groups, from the US-based WasteZero and the UK's ZeroWasteWeek, tell us. Rachelle Strauss's mantra is: "If you go shopping, don't bring home a problem" - in other words, don't be lumped with a bunch of unrecyclable packaging. Readers agree: buy unpacked, say Vinaya, Tom Perks and others. Buy fruit, veg and herbs loose - or better still, Strauss says, try to grow your own - on the windowsill or in a hanging basket if you've no garden.

Join a veg box scheme (also a good way to remind yourself what veg is really shaped like). Use farmers' markets if you're near one, or local shops - butchers, fishmongers - and buy dry goods such as rice, other grains and pulses in bulk, preferably from places that offer refills.

And we can learn to reuse. "We love jars!" says reader Zo Zhou. "To store food, use as a takeaway coffee cup, as a vase, candle holder, storage canisters..."

One of the best things you can do to prevent waste (and readers Emily H and LadyAlba agree) is to learn to cook and become familiar with ingredients. It doesn't even have to be difficult: slow-cookers are a great alternative to ready meals, as are breadmakers. Both work their magic overnight and have produced fresh food by morning.

Another solution: zap wrapping at source. "It sounds a bit radical, but if we all started removing the packaging at checkout, supermarkets might suddenly take notice," says Strauss - a point readers Rozzle and tperrens and Andi Abigail agree on. "Besides, supermarkets have access to better recycling facilities than their customers."

But some say we need nothing less than a revolution in how we consume, as The Story of Stuff has been arguing for a decade. This online campaign reveals the glaring gaps in our broken "materials economy", what fuels our consumer habits, the cycle of "planned obsolescence", and why we're so reliant on so much, well ... stuff. It points the way to a circular economy instead of designing things to fail, to sustainable materials, and stepping off the treadmill of consumerism.

It's not as if we have a choice. This pale blue dot is our only life support system. If we don't look after it, those Thai fishermen won't be the only ones out of a livelihood.

Where you can help

Food redistribution at FareShare - Glasgow
The west Scotland branch of this nationwide surplus food redistribution charity gets meals to the people who need them the most, from hostels for the homeless to refugee centres. Pitch in with your time, food and funds. fareshare.org.uk

Organic, whole-ingredient food: Riverford, Devon
Guy Watson's organic meat and veg box scheme operates on a root-to-fruit, nose-to-tail philosophy: order chicken carcasses (for stock) with your fillets, and tops (for pestos et al) with your veg. Head to their fields on a 'glean', or eat graded-out produce in their restaurants ... riverford.co.uk

Ideas for waste reduction at Waste Less, Save More - Derbyshire
Sainbury's might this week have seen a setback in their bid to halve domestic food waste within 5 years, but households taking part in their 2016 pilot programme in Swadlincote did achieve reductions of up to 75%. Check out their tips, gadgets and apps for inspiration. wastelesssavemore.sainsburys.co.uk

Meals from food waste at Pay As You Feel - West Yorkshire
Leeds's Armley Junk-tion cafe - like all Real Junk Food Project endeavours across the country - diverts ingredients destined for waste, and you pay what you can for the dishes they become. There is now a grocery store operating on the same principle. therealjunkfoodproject.org

Zero Waste cuisine at Silo, East Sussex
Brighton's Doug McMaster won Best Ethical Restaurant at last year's Observer Food Monthly awards for his game-changing zero-waste ethos at Silo: at least 99% of the food they buy is eaten, composted or reused. silobrighton.com

Rescue unpicked veg with the Gleaning Network - Kent
Volunteers from @gleaningKENT were in Thanet this week picking 220 acres of 'excess' cauliflowers that were otherwise set to be destroyed. Find your inner farmer, and a field in need of harvesters near you. feedbackglobal.org

Waste-free fine dining: Scratch Menu, Spring restaurant, London
Skye Gyngell has launched a three-course, £20 early-evening menu using seasonal scraps and food donations at her London restaurant Spring - where most of the Michelin-level mains cost markedly more than that. springrestaurant.co.uk
Topics

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Throwaway culture has spread packaging waste worldwide | Waste packaging

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In 2003, I was told by a restaurant owner on a Thai island that local fishermen used to wrap their lunch in banana leaves, which they would then casually toss overboard when done. That was OK, because the leaves decayed and the fish ate the scraps.

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There are several reasons for the underplaying of this gruesome life-denying event. It's no longer news. "Yep, we have done coral bleaching on the reef. Next."

Tourists are taken to places least affected so they feel the operator has given the tourist value for money. So the word goes south: "The reef looked okay to me."

Vested interests play it down. Businesses that rely on the reef want business as usual. Politicians don't want to be blamed for their criminal inactivity.

People who go to the reef every day become like frogs in water that is slowly brought to the boil. An apt metaphor in this case. They don't notice the change until it's too late.

And scientists have a professional requirement to do their work quietly and dispassionately.

Ultimately, though, the 2300-kilometre reef is worth $6.5 billion a year to the Australian economy (nearly all from tourism) and provides employment for 70,000 people in tourism, aquaculture, fishing and so on, mostly in tourism that depends directly on a healthy reef. We should be doing everything possible, even if our action on climate change can only be a small contribution pat of the needed global action.

The inaction on climate change makes other actions to help the reef that much more important. We must stop agricultural run-off of phosphates, which promotes the growth of the bad slimy algae that attack bleached coral. We must stop dredging run-off from ports, which increases turbidity of the water and denies coral any hope of recovering from bleaching.

We dive and or snorkel on the reef from our yacht and/or its dinghy about 10 to 15 times a year. Yes, I'd seen the bleaching in 2016 on the outer reef between 20 and 30 kilometres offshore. I was appalled at the destruction of swathes of blue staghorn coral that was either white or covered in slimy algae. This coral is usually in sand away from the main reef, where not many people are taken. But there was a lot of plate, brain and cabbage-leaf coral on the main reef that had survived.

This is now no longer about the legacy we hand to our children and grandchildren. The reef will die in the lifetime of us grandparents.

Maybe the combination of climate change with El Nino, fewer cyclones to well up colder water and lower rainfall to cool the top of the ocean was a perfect storm of destruction that would only happen in 2015-16. Maybe, I'd thought, the reef could recover before such an event recurred, in time for climate change to be reversed.

Yet that hope was dashed last weekend with a trip to the Low Isles, 13 kilometres off Port Douglas. The seas were calm, so we could go out to the eastern (windward) edge of the reef a fair distance from Low Islands itself, where the reef seems to have escaped large bleaching and where the tourists quite reasonably are taken by the half dozen vessels that go there each day.

Hitherto, the dive or snorkel off the eastern edge of the reef off Low Island was a gem if the visibility was good. The Low Isles have been a totally protected zone for more than 30 years and the high tourist numbers well managed. As a result, fish, turtles and reef sharks are abundant. But for how long? As we drove in the dinghy across the reef at mid-tide looking for the drop-off, we could see that every bit of reef in water shallower than three metres was bleached. Underwater, it was bleached as far as the eye could see.

It was as if a gang had gone into the Californian national park and ring-barked half the giant sequoia trees, and governments and people said the gang's coming back next year to ring-bark half of what's left - and we are doing nothing.

It's as if someone had gone out to the Serengeti and machine-gunned the wildebeests and said "we're coming back next year to gun down the zebras, and no one is going to do anything".

The reef last weekend was a palpable contrast to the vibrant colours I saw there two years ago. And what a palpable contrast to the first time I dived on the reef in 1985 with my then 14-year-old daughter, who had just got her diving certificate. Alas, this is now no longer about the legacy we hand to our children and grandchildren. At this rate, the reef will die in the lifetime of us grandparents.

There was no pleasure going underwater last weekend. I was beyond even shock or anger. Tears welled up in my diving mask. So much bleaching, so little healthy surviving coral. It made me want to cry.

What have we done? The rest is in the pictures: each 1000 words of shameful death warrant.
crispinhull.com.au

Opinion writer

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I saw the Great Barrier Reef die last weekend, and I wept

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There are several reasons for the underplaying of this gruesome life-denying event. It's no longer news. "Yep, we have done coral bleaching on the reef. Next." Tourists are taken to places least affected so they feel the operator has given the tourist value for money.

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View Slideshow

The ocean is full of strange and mysterious creatures, including a huge sea slug. Adventurer and YouTube show host Coyote Peterson checks out some of these crazy marine creatures on his Brave Wilderness show Beyond the Tide, and this week with "tide pool expert" Aron Sanchez, he found a creature you probably didn't even know existed: a super huge sea slug. The Black Sea Hare is about two feet long.

Peterson and Sanchez visited Los Angeles tide pools to find the Black Sea Hare, and searched for a while before they found one. The particular specimen they discovered weighed an estimated ten pounds, but the Black Sea Hare can ultimately weigh as much as 30 pounds. The slimy slug stretched along the length of Peterson's forearm, leaving oodles of sticky mucus behind.
Related: Octopuses are taking over the oceans, and no one knows why
While few of us have probably held one of these giant slugs, they can be spotted " in abundance" along America's Pacific Coast. As Peterson held the Black Sea Hare, Sanchez found a Brown Sea Hare to hold up for comparison. The Brown Sea Hare is big in its own right - it can grow up to over a foot long and weigh five pounds - but it's dwarfed by the gargantuan Black Sea Hare.

While the Black Sea Hare may look like something out of science fiction, Sanchez assured the audience it wasn't dangerous to Peterson. The black slug doesn't bite, isn't toxic, and eats a vegetarian diet, feasting mainly on kelp and algae.

On the Brave Wilderness YouTube channel, Peterson also hosts three other nature adventure shows, Breaking Trail, Coyote's Backyard, and Dragon Tails. The channel releases new videos every Tuesday. On his website, Peterson says he believes it's best to share animals with his viewers " right from their natural environment " and aims to allow viewers to experience these animals through his videos.

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Meet the enormous black sea slug that's bigger than a chihuahua

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View Slideshow The ocean is full of strange and mysterious creatures, including a huge sea slug. Adventurer and YouTube show host Coyote Peterson checks out some of these crazy marine creatures on his Brave Wilderness show Beyond the Tide, and this week with "tide pool expert" Aron Sanchez, he found a creature you probably didn't even know existed: a super huge sea slug.

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The issue can be overwhelming. The science is complicated. Predictions about the fate of the planet carry endless caveats and asterisks.

We get it.

So we've put together a list of quick answers to often-asked questions about climate change. This should give you a running start on understanding the problem.

1. 1. How much is the planet warming up?

2 degrees is actually a significant amount.

As of early 2017, the Earth had warmed by roughly 2 degrees Fahrenheit, or more than 1 degree Celsius, since 1880, when records began at a global scale. That figure includes the surface of the ocean. The warming is greater over land, and greater still in the Arctic and parts of Antarctica.

The number may sound low. We experience much larger temperature swings in our day-to-day lives from weather systems and from the changing of seasons. But when you average across the entire planet and over months or years, the temperature differences get far smaller - the variation at the surface of the Earth from one year to the next is measured in fractions of a degree. So a rise of 2 degrees Fahrenheit since the 19th century is actually high.

The substantial warming that has already occurred explains why much of the world's land ice is starting to melt and the oceans are rising at an accelerating pace. The heat accumulating in the Earth because of human emissions is roughly equal to the heat that would be released by 400,000 Hiroshima atomic bombs exploding across the planet every day.

Scientists believe most and probably all of the warming since 1950 was caused by the human release of greenhouse gases. If emissions continue unchecked, they say the global warming could ultimately exceed 8 degrees Fahrenheit, which would transform the planet and undermine its capacity to support a large human population.

2. 2. How much trouble are we in?

For future generations, big trouble.

The risks are much greater over the long run than over the next few decades, but the emissions that create those risks are happening now. This means the current generation of people is dooming future generations to a more difficult future.

How difficult?

Over the coming 25 or 30 years, scientists say, the climate is likely to resemble that of today, although gradually getting warmer, with more of the extreme heat waves that can kill vulnerable people. Rainfall will be heavier in many parts of the world, but the periods between rains will most likely grow hotter and drier. The number of hurricanes and typhoons may actually fall, but the ones that do occur will draw energy from a hotter ocean surface, and therefore may be more intense. Coastal flooding will grow more frequent and damaging, as is already happening.

Longer term, if emissions continue to rise unchecked, the risks are profound. Scientists fear climate effects so severe that they might destabilize governments, produce waves of refugees, precipitate the sixth mass extinction of plants and animals in the Earth's history, and melt the polar ice caps, causing the seas to rise high enough to flood most of the world's coastal cities.

All of this could take hundreds or even thousands of years to play out, but experts cannot rule out abrupt changes, such as a collapse of agriculture, that would throw civilization into chaos much sooner. Bolder efforts to limit emissions would reduce these risks, or at least slow the effects, but it is already too late to eliminate the risks entirely.

3. 3. Is there anything I can do about climate change?

Fly less, drive less, waste less.

You can reduce your own carbon footprint in lots of simple ways, and most of them will save you money. You can plug leaks in your home insulation to save power, install a smart thermostat, switch to more efficient light bulbs, turn off the lights in any room where you are not using them, drive fewer miles by consolidating trips or taking public transit, waste less food and eat less meat.

Perhaps the biggest single thing individuals can do on their own is to take fewer airplane trips; just one or two fewer plane rides per year can save as much in emissions as all the other actions combined. If you want to be at the cutting edge, you can look at buying an electric or hybrid car, putting solar panels on your roof, or both.

If you want to offset your emissions, you can buy certificates, with the money going to projects that protect forests, capture greenhouse gases and so forth. Some airlines sell these to offset emissions from their flights. You can also buy offset certificates in a private marketplace, from companies such as TerraPass; some people even give these as holiday gifts. In states that allow you to choose your own electricity supplier, you can often elect to buy green electricity; you pay slightly more, and the money goes into a fund that helps finance projects like wind farms.

Leading companies are also starting to demand clean energy for their operations. You can pay attention to company policies, patronize the leaders, and let the others know you expect them to do better.

In the end, though, experts do not believe the needed transformation in the energy system can happen without strong state and national policies. So speaking up and exercising your rights as a citizen matters as much as anything else you can do.

4. 4. What's the optimistic case?

Several things have to break our way.

In the best case that scientists can imagine, several things happen: Earth turns out to be less sensitive to greenhouse gases than currently believed; plants and animals manage to adapt to the changes that have already become inevitable; human society develops much greater political will to bring emissions under control; and major technological breakthroughs occur that help society to limit emissions and to adjust to climate change.

Some technological breakthroughs are already making cleaner energy more attractive. In the United States, for instance, coal has been losing out to natural gas as a power source, as new drilling technology has made gas more abundant and cheaper; for a given amount of power, gas cuts emissions in half. In addition, the cost of wind and solar power has declined so much that they are now the cheapest power source in a few places, even without subsidies.

Unfortunately, scientists and energy experts say the odds of all these things breaking our way are not very high. The Earth could just as easily turn out to be more sensitive to greenhouse gases as less. Global warming seems to be causing chaos in parts of the natural world already, and that seems likely to get worse, not better. So in the view of the experts, simply banking on rosy assumptions without any real plan would be dangerous. They believe the only way to limit the risks is to limit emissions.

5. 5. Will reducing meat in my diet really help the climate?

Agriculture of all types produces greenhouse gases that warm the planet, but meat production is especially harmful - and beef is the most environmentally damaging form of meat. Some methods of cattle production demand a lot of land, contributing to destruction of forests; the trees are typically burned, releasing carbon dioxide into the atmosphere. Other methods require huge amounts of water and fertilizer to grow food for the cows.

The cows themselves produce emissions of methane, a potent greenhouse gas that causes short-term warming. Meat consumption is rising worldwide as the population grows, and as economic development makes people richer and better able to afford meat.

This trend is worrisome. Studies have found that if the whole world were to start eating beef at the rate Americans eat it, produced by the methods typically used in the United States, that alone might erase any chance of staying below an internationally agreed-upon limit on global warming. Pork production creates somewhat lower emissions than beef production, and chicken lower still. So reducing your meat consumption, or switching from beef and pork to chicken in your diet, are moves in the right direction. Of course, as with any kind of behavioral change meant to benefit the climate, this will only make a difference if lots of other people do it, too, reducing the overall demand for meat products.

6. 6. What's the worst case?

That is actually hard to say, which is one reason scientists are urging that emissions be cut; they want to limit the possibility of the worst case coming to pass.

Perhaps the greatest fear is a collapse of food production, accompanied by escalating prices and mass starvation. It is unclear how likely this would be, since farmers are able to adjust their crops and farming techniques, to a degree, to adapt to climatic changes. But we have already seen heat waves contribute to broad crop failures. A decade ago, a big run-up in grain prices precipitated food riots around the world and led to the collapse of at least one government, in Haiti.

Another possibility would be a disintegration of the polar ice sheets, leading to fast-rising seas that would force people to abandon many of the world's great cities and would lead to the loss of trillions of dollars worth of property and other assets. In places like Florida and Virginia, towns are already starting to have trouble with coastal flooding.

Scientists also worry about other wild-card events. Will the Asian monsoons become less reliable, for instance? Billions of people depend on the monsoons to provide water for crops, so any disruptions could be catastrophic. Another possibility is a large-scale breakdown of the circulation patterns in the ocean, which could potentially lead to sudden, radical climate shifts across entire continents.

7. 7. ​Will a technology breakthrough help us?

Even Bill Gates says don't count on it, unless we commit the cash.

As more companies, governments and researchers devote themselves to the problem, the chances of big technological advances are improving. But even many experts who are optimistic about technological solutions warn that current efforts are not enough. For instance, spending on basic energy research is only a quarter to a third of the level that several in-depth reports have recommended. And public spending on agricultural research has stagnated even though climate change poses growing risks to the food supply. People like Bill Gates have argued that crossing our fingers and hoping for technological miracles is not a strategy - we have to spend the money that would make these things more likely to happen.

8. 8. How much will the seas rise?

The real question is not how high, but how fast.

The ocean is rising at a rate of about a foot per century. That causes severe effects on coastlines, forcing governments and property owners to spend tens of billions of dollars fighting erosion. But if that rate continued, it would probably be manageable, experts say.

The risk is that the rate will accelerate markedly. If emissions continue unchecked, then the temperature at the Earth's surface could soon resemble a past epoch called the Pliocene, when a great deal of ice melted and the ocean rose by something like 80 feet compared to today. A recent study found that burning all the fossil fuels in the ground would fully melt the polar ice sheets, raising the sea level by more than 160 feet over an unknown period. Many coastal experts believe that even if emissions stopped tomorrow, 15 or 20 feet of sea-level rise is already inevitable.

The crucial issue is probably not how much the oceans are going to rise, but how fast. And on that point, scientists are pretty much flying blind. Their best information comes from studying the Earth's history, and it suggests that the rate can on occasion hit a foot per decade, which can probably be thought of as the worst case. Even if the rise is much slower, many of the world's great cities will flood eventually. Studies suggest that big cuts in emissions could slow the rise, buying crucial time for society to adapt to an altered coastline.

9. 9. Are the predictions reliable?

They're not perfect, but they're grounded in solid science.

The idea that Earth is sensitive to greenhouse gases is confirmed by many lines of scientific evidence. For instance, the basic physics suggesting that an increase of carbon dioxide traps more heat was discovered in the 19th century, and has been verified in thousands of laboratory experiments.

Climate science does contain uncertainties, of course. The biggest is the degree to which global warming sets off feedback loops, such as a melting of sea ice that will darken the surface and cause more heat to be absorbed, melting more ice, and so forth. It is not clear exactly how much the feedbacks will intensify the warming; some of them could even partly offset it. This uncertainty means that computer forecasts can give only a range of future climate possibilities, not absolute predictions.

But even if those computer forecasts did not exist, a huge amount of evidence suggests that scientists have the basic story right. The most important evidence comes from the study of past climate conditions, a field known as paleoclimate research. The amount of carbon dioxide in the air has fluctuated naturally in the past, and every time it rises, the Earth warms up, ice melts and the ocean rises. A hundred miles inland from today's East Coast of the United States, seashells can be dug from ancient beaches that are three million years old, a blink of an eye in geologic time.

These past conditions are not a perfect guide to the future, because humans are pumping carbon dioxide into the air far faster than nature has ever done. But they show it would be foolish to assume that modern society is somehow immune to large-scale, threatening changes.

10. 10. Why do people question the science of climate change?

Most of the attacks on climate science are coming from libertarians and other political conservatives who do not like the policies that have been proposed to fight global warming. Instead of negotiating over those policies and trying to make them more subject to free-market principles, they have taken the approach of blocking them by trying to undermine the science.

This ideological position has been propped up by money from fossil-fuel interests, which have paid to create organizations, fund conferences and the like. The scientific arguments made by these groups usually involve cherry-picking data, such as focusing on short-term blips in the temperature record or in sea ice, while ignoring the long-term trends.

The most extreme version of climate denialism is to claim that scientists are engaged in a worldwide hoax to fool the public so that the government can gain greater control over people's lives. As the arguments have become more strained, many oil and coal companies have begun to distance themselves publicly from climate denialism, but some are still helping to finance the campaigns of politicians who espouse such views.

11. 11. Is crazy weather tied to climate change?

Scientists have published strong evidence that the warming climate is making heat waves more frequent and intense. It is also causing heavier rainstorms, and coastal flooding is getting worse as the oceans rise because of human emissions. Global warming has intensified droughts in regions like the Middle East, and it may have strengthened a recent drought in California.

In many other cases, though, the linkage to global warming for particular trends is uncertain or disputed. That is partly from a lack of good historical weather data, but it is also scientifically unclear how certain types of events may be influenced by the changing climate.

Another factor: While the climate is changing, people's perceptions may be changing faster. The Internet has made us all more aware of weather disasters in distant places. On social media, people have a tendency to attribute virtually any disaster to climate change, but in many cases there is little or no scientific support for doing so.

12. 12. Will anyone benefit from global warming?

Countries with huge, frozen hinterlands, including Canada and Russia, could see some economic benefits as global warming makes agriculture, mining and the like more possible in those places. It is perhaps no accident that the Russians have always been reluctant to make ambitious climate commitments, and President Vladimir V. Putin has publicly questioned the science of climate change.

However, both of those countries could suffer enormous damage to their natural resources; escalating fires in Russia are already killing millions of acres of forests per year. Moreover, some experts believe countries that view themselves as likely winners from global warming will come to see the matter differently once they are swamped by millions of refugees from less fortunate lands.

13. 13. Is there any reason for hope?

If you share this with 50 friends, maybe.

Scientists have been warning since the 1980s that strong policies were needed to limit emissions. Those warnings were ignored, and greenhouse gases in the atmosphere were allowed to build up to potentially dangerous levels. So the hour is late.

But after 20 years of largely fruitless diplomacy, the governments of the world are finally starting to take the problem seriously. A deal reached in Paris in late 2015 commits nearly every country to some kind of action. President Trump decided in 2017 to pull the United States out of that deal, saying it would unfairly burden American businesses. But other countries are promising to go forward with it anyway, and some states and cities have defied Mr. Trump by adopting more ambitious climate goals.

Religious leaders like Pope Francis are speaking out. Low-emission technologies, such as electric cars, are improving. Leading corporations are making bold promises to switch to renewable power and stop forest destruction.

What is still largely missing in all this are the voices of ordinary citizens. Because politicians have a hard time thinking beyond the next election, they tend to tackle hard problems only when the public rises up and demands it.

14. 14. How does agriculture affect climate change?

It's a big contributor, but there are signs of progress.

The environmental pressures from global agriculture are enormous. Global demand for beef and for animal feed, for instance, has led farmers to cut down large swaths of the Amazon forest.

Brazil adopted tough oversight and managed to cut deforestation in the Amazon by 80 percent in a decade. But the gains there are fragile, and severe problems continue in other parts of the world, such as aggressive forest clearing in Indonesia.

Scores of companies and organizations, including major manufacturers of consumer products, signed a declaration in New York in 2014 pledging to cut deforestation in half by 2020, and to cut it out completely by 2030. The companies that signed the pact are now struggling to figure out how to deliver on that promise.

Many forest experts consider meeting the pledge to be difficult, but possible. They say consumers must keep up the pressure on companies that use ingredients like palm oil in products ranging from soap to lipstick to ice cream. People can also help the cause by altering their diets to eat less meat, and particularly less beef.

15. 15. Will the seas rise evenly across the planet?

Many people imagine the ocean to be like a bathtub, where the water level is consistent all the way around. In fact, the sea is rather lumpy - strong winds and other factors can cause water to pile up in some spots, and to be lower in others.

Also, the huge ice sheets in Greenland and Antarctica exert a gravitational pull on the sea, drawing water toward them. As they melt, sea levels in their vicinity will fall as the water gets redistributed to distant areas.

How the rising ocean affects particular parts of the world will therefore depend on which ice sheet melts fastest, how winds and currents shift, and other related factors. On top of all that, some coastal areas are sinking as the sea rises, so they get a double whammy.

16. 16. What are 'carbon emissions?'

Here's a quick explainer.

The greenhouse gases being released by human activity are often called "carbon emissions," just for shorthand. That is because the two most important of the gases, carbon dioxide and methane, contain carbon. Many other gases also trap heat near the Earth's surface, and many human activities cause the release of such gases to the atmosphere. Not all of these actually contain carbon, but they have all come to be referred to by the same shorthand.

By far the biggest factor causing global warming is the burning of fossil fuels for electricity and transportation. That process takes carbon that has been underground for millions of years and moves it into the atmosphere, as carbon dioxide, where it will influence the climate for many centuries into the future. Methane is even more potent at trapping heat than carbon dioxide, but it breaks down more quickly in the air. Methane comes from swamps, from the decay of food in landfills, from cattle and dairy farming, and from leaks in natural gas wells and pipelines.

While fossil-fuel emissions are the major issue, another major creator of emissions is the destruction of forests, particularly in the tropics. Billions of tons of carbon are stored in trees, and when forests are cleared, much of the vegetation is burned, sending that carbon into the air as carbon dioxide.

When you hear about carbon taxes, carbon trading and so on, these are just shorthand descriptions of methods designed to limit greenhouse emissions or to make them more expensive so that people will be encouraged to conserve fuel.

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united nations framework convention on climate change

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Short Answers to Hard Questions About Climate Change

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The issue can be overwhelming. The science is complicated. Predictions about the fate of the planet carry endless caveats and asterisks. We get it. So we've put together a list of quick answers to often-asked questions about climate change. This should give you a running start on understanding the problem.

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Underwater meadows appear to fight ocean germs

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The seagrasses that sway in coastal currents are more than aquatic groundcover. They can reduce harmful bacteria that might otherwise sicken neighboring animals, new data show.

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Frozen lakes are quiet places. Snow muffles sound. Boaters stay home. Animals do not visit for a drink. For a long time, scientists also thought nothing much was going on below the ice.

Turns out they were wrong.

Many plants, animals and other forms of life hibernate or go dormant in winter. But new research shows that a surprising number remain active in cold months. In fact, some organisms only spring to life once a lake freezes over. Many others survive only by clinging to the ice's underside.

To probe what goes on in these cold worlds, Stephanie Hampton gathered a team of more than 60 scientists from around the world who study freshwater (not salty) lakes. Hampton works at Washington State University in Pullman. As an aquatic ecologist there, she studies how water organisms relate to each other and to their surroundings.

Together, Hampton and her team analyzed more than 100 lakes during several recent winters. These bodies of water were scattered across the Northern Hemisphere and Antarctica. Their work represents the first in-depth survey of a large group of ice-covered freshwater lakes. And what they found surprised even them.

"None of us," Hampton says, "expected life under the ice to be as abundant and diverse as it is."

Scientists braved tough conditions

Gathering the new data wasn't easy. The researchers braved the cold and risked plunging through frozen lakes to collect their data. Some scientists towed rowboats behind them as they trudged across lakes, so they could hop in if the ice started to crack. Others camped out in temporary huts that they built on very thick ice. Still others ventured out onto frozen lakes on snowmobiles or aboard icebreaker boats. (The good news: No one fell through the ice, notes Hampton.)

The researchers carried augers to drill holes through the ice, bottles for collecting the frigid water underneath and buckets for storing chunks of ice. They brought all of these lake samples back to their labs for study.

From there, they calculated how much algae and zooplankton had been growing beneath the winter ice. Algae are aquatic organisms. Zooplankton are tiny aquatic animals that eat algae. (Fish and other lake animals, in turn, eat zooplankton.)

In some lakes, researchers found winter concentrations of algae and zooplankton were higher than what had been present in summer. But those were rare cases. While each lake differed, the average amount of algae growing under the ice tended to be less than one-sixth of summer levels. And much of that algae had been clinging to the underside of the ice.

Winter zooplankton levels were, on average, about a third of summertime levels. Unlike algae, zooplankton float freely within the frigid ice-capped water.

The winter levels "may not sound like a lot," Hampton says. Still, it was higher than expected and "shows lakes are still alive under the ice," she says. This matters because many freshwater lakes are losing their ice cover. Climate change has been warming Earth's air and water. Lakes no longer freeze as much as they did in the past. The ice also may not be as thick or last as long.

What happens if there is no ice for algae to cling onto? Does that mean less winter food for the zooplankton? And could that mean fewer zooplankton for fish to dine on during the winter?

Hampton's team can't say yet. So far, they know only what current conditions are. But that information gives them a baseline - a starting point - against which they can compare future conditions.

"No one is sure how having less ice will affect lakes. But having this baseline will help us be better prepared," says Hampton.

Understanding how climate change affects lakes is important because people rely on these bodies of water for many things, such as drinking and irrigating crops. Fish that make these lakes their home also can be an important local source of food.

Hampton and her team described their new data in the Nov. 27, 2016 Ecology Letters,

Ocean research offers clues to what is at stake

That new work follows in the footsteps of marine researchers. These are scientists who study oceans. Marine scientists started to examine life under ocean ice a few decades ago. They were the first to discover that some algae live by clinging to the bottom of floating ice.

Unlike freshwater researchers, marine scientists also discovered that a lot of ocean algae live in water trapped between ice crystals. The salt water from the ocean freezes at a lower temperature than freshwater. Tiny salt water channels form in the ice. "These channels are perfect places for algae to hang out," explains Warwick Vincent. He is an aquatic researcher at Laval University in Quebec City, Canada. He has studied both freshwater and marine ice.

"You don't see these channels in freshwater," he notes, "because there isn't enough salt in the water."

A few years after the discovery of sea-ice algae, research showed that these organisms are crucial to the ocean food web. Just as in freshwater lakes, sea-ice algae are an important food for zooplankton. Zooplankton in turn feed larger ocean creatures, such as fish and some whales.

Marine researchers learned that the critical time for sea algae to grow runs from late winter to early spring. Temperatures at this point begin to rise and ice starts to thin. That thinning ice lets in more light, which the algae use to produce food from carbon dioxide and water. Through this process, called photosynthesis, sunlight stimulates the growth of algae.

The timing is perfect, because this is also when zooplankton begin to reproduce. It means baby zooplankton have a banquet of algae on which to feed.

But because of global warming, spring - and its balmy temperatures - has begun arriving earlier in the year. This leads to an earlier melting of the sea ice. Marine researchers worry that algae may start growing too early - before zooplankton start to reproduce. Then when zooplankton are ready for their algal feast, many of those algae may have finished growing and fallen to the bottom of the ocean.

Marine scientists don't know yet if this is happening: "I don't think there is good enough data to test this at present," says Vincent.

With early melting and less ice, zooplankton may face big troubles. That, in turn, might mean that zooplankton-loving predators - such as seabirds, fish and whales - will go hungry. For now, the scientists can't predict how losing sea-ice algae might affect zooplankton and the larger creatures that feed on them.

Something similar could be happening in lakes, the freshwater scientists worry. Hampton and her team hope their baseline data will help them find out. Still, they have good reason to suspect that what happens in the winter can affect lake life the rest of the year.

This is especially true for lakes that let a lot of sunlight in through ice. This happens when frozen lakes are not covered in snow (which blocks the light.) As in the ocean, sunlight stimulates the growth of algae - which are food for zooplankton.

Until the ice melts in the spring, cold-loving algae and zooplankton are an important food source for newly hatched fish. Later, when spring arrives, the young fish can turn to algae and zooplankton that grow in warmer water.

The concern, right now, is what may happen if there is less ice throughout the winter months.

'Unusual' Lake Erie

Hampton's study is important for another reason: It is the first to compare winter and summer conditions for so many lakes, notes Stuart Jones. He works for University of Notre Dame in South Bend, Ind. There ,he studies aquatic ecosystems. The global lakes study was able to glean "a surprisingly large amount of data through cooperation and communication across many, many research groups in many areas of the world," notes Jones.

One participant was Maggie Xenopoulos. She's an aquatic ecologist in Canada at Trent University in Peterborough, Ontario. Xenopoulos analyzed water and ice samples from Lake Erie. One of the Great Lakes, it borders both Canada and the United States.

"Lake Erie is unusual because it has a lot of winter algae," says Xenopoulos. Those algae cling to the underside of the ice, tinging it brown. This ice may look like mud and sand, she says, "but it's teeming with life."

In fact, Xenopoulos found that the amount of algae in Lake Erie during the winter can be similar to what's there in summer. This happened mostly in areas where snow rarely blankets ice.

In one 2012 study, another team showed that concentrations of winter algae can be higher than those in summer. The most common algae was a species called Aulacoseira. It blooms only in the winter. (A bloom is a rapid growth of something - in this case, algae.)

Previous research showed wintertime algae play an important role in Lake Erie. They consume nutrients, such as nitrogen and phosphorus. Lake Erie has unnaturally high levels of both. That's mostly because of runoff from farmers' fields. Farmers fertilize their fields to boost crop growth and yields. But crops do not absorb all of those nutrients. When it rains, the unabsorbed nitrogen and phosphorus wash into waterways that feed the lake.

If Lake Erie's ice declines significantly, Xenopoulos worries, so too might winter algae. Then the algae won't be around to consume their share of the lake's excess nitrogen and phosphorus. This risks boosting summer levels of those nutrients.

This is a problem because a type of photosynthetic bacteria called cyanobacteria springs to life as the water warms. Like algae, these bacteria feed on nitrogen and phosphorous. When there is a lot of these nutrients in the water, the bacteria can bloom, creating huge patches of blue-green scum. Some cyanobacteria produce a toxin that can poison fish - and people.

Such blooms can have big consequences. Many towns and cities that surround Lake Erie get their drinking water from the lake. In August 2014, there was a very large, toxin-producing cyanobacteria bloom near Toledo, Ohio. To protect people, the city shut down for three days the supply of drinking water to more than 400,000 Toledo-area residents. Scientists worry that incidents like this could become more common if the winter algae decline.

"This is starting to look like a really bad story," says Xenopoulos. "If the ice isn't there, nutrients stick around to create even bigger summertime cyanobacteria blooms."

Hampton says Xenopoulos and the other team members will continue their studies. In a few years, they hope to be able to predict better the impacts of declining lake ice.

"We are losing ice very quickly right now," she says. "We really need to understand how climate change will affect lake food webs and water quality."

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Under blanket of ice, lakes teem with life

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Frozen lakes are quiet places. Snow muffles sound. Boaters stay home. Animals do not visit for a drink. For a long time, scientists also thought nothing much was going on below the ice. Turns out they were wrong. Many plants, animals and other forms of life hibernate or go dormant in winter.

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DENVER, Colo. - Fracking is a procedure used to extract oil or gas from deep underground. The process uses lots of water and lots of chemicals. This means it also produces lots of watery wastes. A series of new tests now show those wastes may be toxic.

Scientists found the wastewater can contain chemicals that alter the action of the body's hormones. In mice exposed in the womb, the heart and reproductive tissues did not develop normally. Researchers described their new findings here on March 23 at the national meeting of the American Chemical Society.

Many energy companies around the world use hydraulic fracturing - or fracking - to release oil, and especially gas. (That gas usually comes from deposits of shale, a type of rock.) But this process has been controversial. Oil and gas companies inject chemicals deep into wells to flush out the gas and oil. Those chemicals can contaminate groundwater, some studies have shown.

For the new study, researchers worked with human cells and mice. First, they looked for signs in cells that the chemicals altered signaling by any of five different hormones. Hormones are natural chemicals produced by the body's endocrine system. That system produces hormones that tell various tissues when to turn on or off a particular important action.

For instance, hormones help people process food, identify hunger and recognize when it's time to sleep. Hormones also tell tissues when it's time to grow. Puberty and reproduction, for instance, are controlled by a complex series of hormonal changes.

In the new lab tests, the fracking-fluid ingredients each altered the effects of at least one hormone.

Signs of animal impacts

Christopher Kassotis works at the University of Missouri in Columbia. He's also the study's lead researcher and an endocrinologist (EN-doh-krin-OLL-uh-gizt), someone who studies hormone impacts. For the new study, his team combined 23 hormone-disrupting chemicals known to have been used by oil and gas companies for fracking.

Hormone-like pollutants can do harm in one of two ways. Some may block a true hormone's signal. Others may fake out the body, turning on some activity normally triggered by a real hormone.

Energy companies seldom disclose the precise recipe of chemicals in their fracking fluids. But lists of some fracking chemicals have been published. (Such ingredients can include chemicals that kill microbes or that inhibit rust and other forms of corrosion.) Kassotis and his coworkers tried to mix these chemicals in amounts that might roughly match levels in real fracking wastewater.

For their new study, the researchers gave pregnant mice drinking water that contained a cocktail of these fracking chemicals. Male offspring of these mice grew up overweight. Those males also had heavier hearts compared to mice whose mothers hadn't drunk water containing fracking chemicals. (The researchers are still analyzing the data from female offspring.)

Finally, male mice exposed in the womb to the fracking chemicals developed bigger testes. "This is not actually a good thing," said Kassotis. Larger testes can lead to cysts and other health problems, he says.

The effects seen in the male offspring echo health problems seen in people: Studies have linked other hormone disrupters to obesity. And epidemiologists have found an increased rate of heart defects in babies whose mothers live near natural gas wells, including fracking sites.

It's unlikely people would ever encounter doses of fracking chemicals as high as those given to the mice, Kassotis says. But some human exposures might not be too much lower, he adds. Fracking fluids and wastewaters often spill, he explains. This can taint soils and rivers. In January, for example, a leaking pipeline spewed more than 11 million liters (2.9 million gallons) of fracking wastewater. That pollution entered a stream near Williston, N.D.

Earlier, Kassotis's team collected samples of soil and water from areas where spills had occurred in Colorado. Hormone-disrupting chemicals showed up.

How dangerous are these exposures to people? No one knows, says Karl Linden. He's an environmental engineer at the University of Colorado Boulder. But he is developing ways to clean up fracking wastewater. He hopes these techniques will help remove hormone mimicking pollutants.

Scientists don't know all of the hormone-like chemicals in fracking fluid yet, Linden notes. But, he adds, they're definitely there.

Power Words

(for more about Power Words, click here)

cyst A group of cells that form a type of bubble-like shell or sac. Some cysts develop as a result of disease or tissue damage. Others may develop as a normal, protective during certain phases of a parasite's maturation.

endocrine disruptor A substance that mimics the action (sometimes well, sometimes poorly) of one of the body's natural hormones. By doing this, the fake hormone can inappropriately turn on, speed up or shut down important cellular processes.

endocrine system The hormones (chemicals secreted by the body) and the tissues in which they turn on (or off) cellular action. Medical doctors who study the role of hormones in health and disease are known as endocrinologists. So are the biologists who study hormone systems in non-human animals.

endocrinologists Doctors who specialize in conditions affecting the production of hormones or the body's response to hormones.

engineer A person who uses science to solve problems. As a verb, to engineer means to design a device, material or process that will solve some problem or unmet need.

epidemiologist Like health detectives, these researchers figure out what causes a particular illness and how to limit its spread.

hormone (in zoology and medicine) A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body. (in botany) A chemical that serves as a signaling compound that tells cells of a plant when and how to develop, or when to grow old and die.

hormone blocker Medications used to suspend the natural development of puberty. Some environmental pollutants may also bind to hormone receptors and block their action. These too may perturb the natural development of a male or female, potentially lending them traits typical of the sex expected based upon their genetic inheritance.

hydraulic fracturing, or fracking The cracking open of undergound rocks by introducing liquid at high pressure, especially to extract natural gas. Those cracks are then held open by sand that had been added to the fracking fluid.

obesity Extremely overweight. Obesity is associated with a wide range of health problems, including type 2 diabetes and high blood pressure. It can perturb healthy hormone signaling. It can even be due to impaired hormone signaling.

pollutant A substance that taints something - such as the air, water, our bodies or products. Some pollutants are chemicals, such as pesticides. Others may be radiation, including excess heat or light. Even weeds and other invasive species can be considered a type of biological pollution.

testis (plural: testes) The organ in the males of many animal species that makes sperm, the reproductive cells that fertilize eggs. This organ also is the primary site that makes testosterone, the primary male sex hormone.

toxic Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.

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Fracking wastes may be toxic, tests show

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DENVER, Colo. - Fracking is a procedure used to extract oil or gas from deep underground. The process uses lots of water and lots of chemicals. This means it also produces lots of watery wastes. A series of new tests now show those wastes may be toxic.

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Humans as superpredators

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Boats and boating--Equipment and supplies

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Every action has a cost. That's as true for driving a car as it is for growing food and delivering it to your dinner plate. A team of researchers has just tallied the costs of producing meat versus other types of foods for human diners. They find that meat production - from farm to fork - releases more climate-warming pollution that does producing fruits, vegetables, nuts and grains. A lot more.

Their calculations suggest that people could do a lot to slow global warming if they limited how much meat they eat.

There are plenty of "costs" to producing any goods, including food. Sure, people pay money for the food as well as the fuel needed to get groceries to the store or restaurant. But those are just the most visible costs. Producing things also takes resources. For foods, this includes the water used to irrigate crop fields. It also includes the fertilizer and chemicals that boost plant growth and fight pests. And don't forget the gasoline and diesel that fuel plows and also those trucks that take crops to market.

Along with those resources are wastes: pollution. Manure is one obvious pollutant associated with meat production. But there are others, including the air pollutants spewed by tractors that plow fields and the trucks that move feed to the animals and animals to the slaughterhouse. Peter Scarborough at the University of Oxford in England, and his colleagues decided to tally some of the less-visible pollution created by food production.

They focused on greenhouse gases. In the atmosphere, these gases trap heat from sunlight. Lately they've been trapping too much, causing a sort of mild, global fever. Overall, food production accounts for one-fifth of this type of pollution.

One greenhouse gas emitted through the production of our food is carbon dioxide, or CO ₂. It's released by the burning of fossil fuels, such as gasoline and natural gas. They are used to power farm machinery, to take foods to market (and home), to store foods awaiting processing and to cook foods. The researchers also tallied methane. Fermentation in the guts of ruminant livestock - mostly cows - releases this gas. And the scientists calculated the nitrous oxide released during the plowing and fertilizing of crop fields.

All three gases are important. CO ₂ is the greenhouse gas released in the highest volume. But methane and nitrous oxide stay in the atmosphere far longer than CO ₂ does. As such, they are more potent, molecule for molecule, in warming Earth's atmosphere.

A computer converted the methane and nitrous-oxide emissions for each person's diet into its carbon-dioxide "equivalent." That's the amount of CO ₂ needed to warm Earth's atmosphere by the same amount as the methane or nitrous oxide would.

Switching from meat-rich meals to vegetarian ones would reduce the average meat eater's CO ₂ equivalents - also known as its carbon footprint - by 1,230 kilograms (about 1.4 U.S. tons) per year, the new study calculated. Scarborough's team presented its findings in the July issue of Climatic Change.

How they calculated food's 'carbon footprint'

In the 1990s, a survey asked 65,000 adults what they typically had eaten throughout the past year. Scarborough's team fed those data into a computer. The researchers also included the amount of greenhouse gases linked with producing nearly 100 common foods. Then the computer matched those greenhouse-gas amounts to the mix of foods each person had reported eating.

Some people had eaten lots of meat. Others hadn't. Some had been big fish eaters. Others weren't. All people ate some plant-based foods, such as salads, grains, bread, beans or fruit. Some reported being vegetarians. That means they downed only plant-based foods with the exceptions of possibly eggs, fish or milk. Others, vegans, reported eating no meat, poultry, fish or dairy foods (including cheese, butter and yogurt).

The diet of someone whose meals included an average of 50 to 99 grams (1.8 to 3.5 ounces) of meat each day would be responsible for the daily release of 5.6 kilograms (12.4 pounds) of CO₂ equivalents, according to the new analysis. Vegans would contribute only 2.9 kg (6.4 lbs) of CO ₂ equivalents, the researchers calculated. Indeed, those vegans had the lowest diet-linked greenhouse-gas emissions. Vegetarians had the next lowest emissions, followed by people who ate fish but no red meat or poultry.

Scientists don't expect many people will give up eating meat entirely. In fact, in England the trend has been in the opposite direction. The share of people there who consider themselves vegetarians or vegans fell from 5 percent in 2000 to just 2 percent by 2010. Over the same period, meat consumption climbed 7.8 percent - to 84.2 kg (186 lbs) per person.

U.S. data show that as of 2012, 4 percent of men and 7 percent of women considered themselves vegetarians. However, Americans continue to consume more meat than people in the United Kingdom and Europe. Each year the average American adult downs about 120 kg (265.7 lbs) of meat.

Still, the new study "demonstrates that reducing the intake of meat and other animal-based products can make a valuable contribution to climate change mitigation," its authors conclude. And there's another advantage to reducing meat consumption, the researchers point out. Compared to meat, more plant-based food calories can be grown on a plot of land - and with less water and other resources. In places where many people are going hungry, as they are in large parts of the world, raising meat may make it harder to ensure that everyone gets enough to eat.

Beyond greenhouse gases

"I think it's interesting," Danielle Nierenberg said of the new study. She's president of Food Tank, a food-policy organization based in Washington, D.C. Looking at greenhouse gases is important, she says. But, she adds, it's just one of many environmental costs of foods.

"The more we think about what we're eating, and food's role in sustainability or in climate change, that's a good thing," she says. But, she adds, "more needs to be done to be sure that

we're capturing everything." By that she means scientists want to be sure that they are not missing important environmental "costs" of producing food.

Those costs may have to do with the resources. Some crops are water hogs, which can be a problem in areas with little rain. Others may require a lot of processing - using water and plenty of expensive energy - to clean, cook-up, package or deliver foods to grocery shoppers.

And then there are a range of less visible environmental problems. Animals may harden the soils, making the land less likely to soak up water when it rains. Often farmers rely on weed killers and pest killers to improve the size of their crop harvests. Many of those chemicals can be toxic to wildlife and people. Some fertilizers can pollute groundwater. Plowing fields can lead to erosion. That can diminish the fertility of soils.

Finally, Nierenberg notes, even for meat, "not all meat is created equal." Some farmers pen cattle in feedlots to fatten them quickly. This requires feeding them an unnatural diet and releases a lot of animal wastes (poop and pee) into a small area. In contrast, some farmers graze their cattle on pastures. Allowing the animals to eat grass and over a broad expanse of land helps ensure that the soil is protected and that native plants are not trampled to death.

There can also be a similar range of environmental differences in the way plant-based foods are farmed. Some can be less wasteful and less polluting than others.

Scarborough's team took a good first step in tallying costs, Nierenberg says. But, she argues, more details will be needed about how foods are grown to truly know which foods - or farm practices - take the biggest toll on Earth's total environment.

Power Words

atmosphere The envelope of gases surrounding Earth or another planet.

carbon dioxide (abbrev. CO ₂) A gas produced by all animals when the oxygen they inhale reacts with the carbon-rich foods that they've eaten. This colorless, odorless gas also is released when organic matter (including fossil fuels like oil or gas) is burned. Carbon dioxide acts as a greenhouse gas, trapping heat in Earth's atmosphere. Plants convert carbon dioxide into oxygen during photosynthesis, the process they use to make their own food.

carbon dioxide equivalents In the atmosphere, carbon dioxide (CO ₂) works as a heat-trapping gas - often called a greenhouse gas. Many other gases - such as methane and nitrous oxide and hydrofluorocarbons - also trap heat, but their lifetime in the atmosphere can be far longer than carbon dioxide's. So to compare the warming potential associated with those other pollutants, scientists often convert them into what they term CO ₂ equivalents. That's the amount of CO ₂ needed to warm Earth's atmosphere by the same amount as those longer-lasting warmers would.

carbon footprint A popular term for measuring the global warming potential of various products or processes. Their carbon footprint translates to the amount of some greenhouse gas - usually carbon dioxide - that something releases per unit of time or per quantity of product.

climate The weather conditions prevailing in an area in general or over a long period.

ecosystem A group of interacting living organisms - including microorganisms, plants and animals - and their physical environment within a particular climate. Examples include tropical reefs, rainforests, alpine meadows and polar tundra.

fermentation The metabolic process of converting carbohydrates (sugars and starches) into short-chain fatty acids, gases or alcohol. Yeast and bacteria are central to the process of fermentation. Fermentation is a process used to liberate nutrients from food in the human gut. It also is an underlying process used to make alcoholic beverages, from wine and beer to stronger spirits.

fertilizer Nitrogen and other plant nutrients added to soil, water or foliage to boost crop growth or to replenish nutrients that removed earlier by plant roots or leaves.

fossil fuels Any fuel (such as coal, oil or natural gas) that has developed in the Earth over millions of years from the decayed remains of bacteria, plant or animals.

greenhouse gas A gas that contributes to the greenhouse effect by absorbing heat. Carbon dioxide is one example of a greenhouse gas.

methane A hydrocarbon with the chemical formula CH4 (meaning there are four hydrogen atoms bound to one carbon atom). It's a natural constituent of what's known as natural gas. It's also emitted by decomposing plant material in wetlands and is belched out by cows and other ruminant livestock. From a climate perspective, methane is 20 times more potent than carbon dioxide is in trapping heat in Earth's atmosphere, making it a very important greenhouse gas.

molecule An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O ₂), but water is made of two hydrogen atoms and one oxygen atom (H ₂ O).

nitrogen oxides Pollutants made up of nitrogen and oxygen that form when fossil fuels are burned. The scientific symbol for these chemicals is NOx (pronounced "knocks"). The principle ones are nitric oxide (NO) and nitrous oxide (NO ₂).

pollutant A substance that taints something - such as the air, water, our bodies or products. Some pollutants are chemicals, such as pesticides. Others may be radiation, including excess heat or light. Even weeds and other invasive species can be considered a type of biological pollution.

sustainability To use resources in a way that they will continue to be available in the future.

vegan A person who subscribes to a fairly extreme form of vegetarianism. Vegans do not eat animal products of any sort, including meat, milk or eggs. Some vegans also avoid use of animal products in their clothing (such as leather, wool or even silk).

vegetarian A person who does not eat red meat (such as beef, bison or pork), poultry (such as chicken or turkey) or fish. Some vegetarians will drink milk and eat cheese or eggs. Some will eat the flesh of fish only, not mammals or birds. Vegetarians get the vast majority of each day's calories from plant-based foods.

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Your food choices affect Earth's climate

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Every action has a cost. That's as true for driving a car as it is for growing food and delivering it to your dinner plate. A team of researchers has just tallied the costs of producing meat versus other types of foods for human diners.

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Pesticides are designed to kill particular classes of organisms. Most target a narrow range of species of insects, mites or nematodes. That doesn't mean they can't, however, also poison other critters, including bees or even people.

Pesticides sold for use around the home tend to be relatively nontoxic or are mixed in concentrations that are not overly strong. They should be relatively safe around people, at least when used as directed. But kids are smaller than adults. That means it takes a smaller dose of pesticide to have an effect inside a child's body. And even low levels of pesticides can cause behavioral problems, trouble concentrating or even cancer, notes the American Academy of Pediatrics (AAP).

That presents a concern, because kids are exposed to a wide variety of pesticides every day, the AAP finds. Shoes track these chemicals into our homes. The wind spreads them beyond the field or garden. Some bug or rodent killers are even designed for use in homes. And traces of pesticides may even taint foods.

That's why the AAP recommends taking steps to reduce pesticide exposure. One way is to eat organic foods. Another is to switch to integrated pest management, or IPM. This takes a natural approach to pest control.

For instance, gardeners or farmers may release ladybugs or other natural predators onto their plants. There, the good bugs munch on the pests. Or growers can plant things that attract birds and other predatory species. Examples include plants that produce yummy berries and seeds, or that provide protective cover for the natural predators. Those species can control pests naturally. They patrol a yard or field snacking on caterpillars, grasshoppers and other animals that may pose a threat to plants.

Recently, some crop scientists have found that certain species of plants naturally produce vapors that act as chemical distress calls. Various insects and other predatory animals have evolved to learn that these scents signal a plant is under attack by a pest. Often a predator will find those pests yummy. Plants that make these distress scents basically recruit their own saviors.

People also can choose certain species of crops or garden plants whose roots exude their own weed killers. These plants include some lawn grasses and garden shrubs. Botanists refer to this type of chemical defense as allelopathy (Ah LEE lo path ee).

IPM practices allow the use of chemical pesticides, but only as a last resort. So consider

allowing a few weeds in the lawn (or hand-pulling them) to avoid the need for poisonous weed killers. Seal cracks around the house to keep spiders, crickets, mice and other pests outside, where they belong. And fix leaky pipes to dry up the water that lures many pests into a building.

Taking such IPM steps can minimize any need for pesticides. That leads to a safer environment for people, pets and welcomed wildlife - including bees.

Power Words

allelopathy A plant's production of chemicals that impair the growth and survival of other plant species.

botany The field of biology that focuses on plants. A scientist in this field is known as a botanist.

evolve To change gradually over generations, or a long period of time.

integrated pest management (abbreviated IPM) The process of using primarily non-chemical steps to reduce pest problems. IPM practices allow the use of chemical pesticides, but only as a last resort.

mite Tiny eight-legged creature related to spiders and ticks. It is not an insect.

organic (in agriculture) Farm products grown without the use of non-natural and potentially toxic chemicals, especially pesticides.

pediatrics Relating to children and especially child health.

pesticide A chemical or mix of compounds used to kill insects, rodents or other organisms harmful to cultivated plants, pet or livestock, or that infest homes, offices, farm buildings and other protected structures.

predator (adjective: predatory) A creature that preys on other animals for most or all of its food.

Alison Pearce Stevens is a former biologist and forever science geek who writes about science and nature for kids. She lives with her husband, their two kids and a small menagerie of cuddly (and not-so cuddly) critters.

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Pesticides are designed to kill particular classes of organisms. Most target a narrow range of species of insects, mites or nematodes. That doesn't mean they can't, however, also poison other critters, including bees or even people. Pesticides sold for use around the home tend to be relatively nontoxic or are mixed in concentrations that are not overly strong.

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Penny Chisholm has had a 35-year love affair-with a microbe. For her, it's been the perfect partner-elusive during courting, a source of intellectual fulfillment, and still full of mystery decades after their introduction during an ocean cruise.

To look at, the object of her passion is just a green mote, floating in vast numbers in the world's oceans. But Chisholm has found hidden complexity within Prochlorococcus, a cyanobacterium that is the smallest, most abundant photosynthesizing cell in the ocean-responsible for 5% of global photosynthesis, by some estimates. Its many different versions, or ecotypes, thrive from the sunlit sea surface to a depth of 200 meters, where light is minimal. Collectively the "species" boasts an estimated 80,000 genes-four times what humans have, and plenty to deal with whatever the world's oceans throw at it. "It's a beautiful little life machine and like a superorganism," Chisholm says. "It's got a story to tell us."

And tell it Chisholm has, to anyone and in any way possible. Her work on the microbe has led to a meeting with a U.S. president, a debate with the Dalai Lama, and co-authorship of science-themed children's books. She even once tried to get the hip-hop star GZA to incorporate the bacterium's mouthful of a name into a rap song for an album he was considering on oceans. "She's really driven to sell Prochlorococcus," says Allison Coe, Chisholm's longtime lab manager. "She wants everyone else to be as passionate and to consider it as amazing as she thinks it is."

The microbe's long climb to recognition mirrors Chisholm's own. Early in her career, as the lone woman, and lone biologist, in the civil engineering department at the Massachusetts Institute of Technology (MIT) in Cambridge, she had to overcome both scientific and cultural hurdles, adopting the latest techniques to reveal Prochlorococcus's secrets while working with other female faculty to get MIT to address gender discrimination. Her quiet persistence inspired others. Chisholm, who in recent years has been awarded the National Medal of Science and named as one of MIT's 13 Institute Professors, sent "an important message for future academicians," says Heidi Sosik, a biological oceanographer at the Woods Hole Oceanographic Institution (WHOI) in Massachusetts. "You don't have to be a blustery, high-profile white guy to make it."

The stature of her microbial partner continues to grow as well. Its influence over climate is now appreciated, for example. And Chisholm and two colleagues will soon lay out evidence for a scenario in which Prochlorococcus is a central actor in evolution. They propose that it is not only responsible for much of the oxygen we breathe today, but also fueled the explosion of early life in the oceans and the ancient rise in oxygen in Earth's atmosphere. As MIT oceanographer Mick Follows put it, Chisholm "has beautifully shown us how this microbe works and how the ocean world is organized."

A microbe's vital stats

Chisholm says that as a woman of her times, she went to college in the 1960s mainly "to find a husband." Nevertheless, as an undergrad, she explored the chemistry of lakes, and-after a professor pushed her-decided to pursue a Ph.D. At the State University of New York in Albany, she studied the 24-hour variation in nutrient cycling in Euglena, a single-cell photosynthesizer like Prochlorococcus, but found in freshwater. She next went to the Scripps Institution of Oceanography in San Diego, California, for a very practical reason-there was more funding for marine microbial ecology than for freshwater.

In 1976, MIT came calling. At the time, its civil engineering department was looking to become more "environmental" by hiring a microbiologist, a trend already evident in many similar departments elsewhere. She accepted but was so convinced she wouldn't get tenure it took many years for her to consider buying a house. It was easy to see why she might not fit in. An old department photo shows a petite, young blonde among a sea of mostly middle-aged white men. Furthermore, the other biologists on campus had a biomedical or molecular bent, quite unlike the fuzzy ecological world she was diving into.

But MIT, through its affiliation with WHOI on Cape Cod, offered Chisholm a chance to go to sea, looking for answers to a question that had begun to captivate her: how microbes influence the ocean. "She had this idea there were new things to discover and [scientists] just needed to find ways of observing the ocean at higher and higher resolution," says Alexandra Worden of the Monterey Bay Aquarium Research Institute in Moss Landing, California, who studies the evolution of ocean microbes.

In the 1980s most of the ocean's freefloating organisms, or plankton, went virtually unseen because they were too small to detect in a light microscope. But other researchers had identified a handful of photosynthetic marine bacteria. Chisholm and her first postdoc Robert Olson decided to sieve seawater with a flow cytometer, a laboratory device that uses a laser to view and sort individual cells, to learn more about them. With it, Olson noticed an unexpected red fluorescing signal so small that they first thought it was electronic noise. But the signal varied depending on the depth and temperature of the water sample being analyzed, suggesting it might come from something alive.

Chisholm wasn't satisfied that they had found a new life form until collaborators photographed the tiny cells under an electron microscope and another group had traced the red signal to the microbe's chlorophyll and other pigments. In 1988, they published their discovery. By 1992, when they named it Prochlorococcus, the "primitive green berry," they realized that they were not the first to see the microbe. But no one had recognized that it represented a new organism. "We were in the right place at the right time with the right instruments to have these cells say who they were," Chisholm says.

For years, because no one could keep Prochlorococcus alive in a lab, the only way to study it was at sea. And even though Brian Palenik, now an oceanographer at Scripps, was finally able to grow it in a test tube in 1990, it took another 10 years before anyone could sustain the pure cultures needed for many experiments. Even today, no one has been able to manipulate Prochlorococcus genetically, a standard approach to studying other organisms.

Despite these challenges, Chisholm was quickly seduced by her team's discovery, suspecting that this simple, abundant organism might be a major player in marine ecology. But just as her relationship with Prochlorococcus was starting to flourish, Chisholm took a detour onto a more public stage, after receiving a call that, she says, "changed my life." Nancy Hopkins, an MIT cancer researcher she casually knew, felt that the school was discriminating against female faculty in lab space, pay, and support. Hopkins had written a letter calling for an investigation and wanted more backers. Chisholm had never considered herself a feminist or activist, but like all but one of the 17 other senior female faculty at the time, she signed on. "We were really upset that things were not changing for women," Chisholm recalls.

They took their concerns to an MIT dean in 1995 and got backing for an investigative committee to collect data on the number of teaching and administrative positions held by women, salaries, sizes of labs, and more. "[Penny] was one of the ones who brought a more positive, 'Let's figure this out' approach," says biogeochemist Diane McKnight of the University of Colorado in Boulder, an alumna of Chisholm's lab.

After working behind the scenes for almost 2 years, the committee made a series of recommendations that the MIT administration quickly embraced. When a summary of the investigation made it into the media in 1999, "it was a shot heard around the world," Chisholm recalls. "It became a big movement." MIT's leaders responded constructively, she adds. "Looking back at the way things were when I first got here and how things are now, there's a tremendous shift," she says.

After helping raise the profile of female scientists, Chisholm drew new attention to her favorite microbe. As she and her students and postdocs grew samples under varied conditions in the lab, they identified five main Prochlorococcus ecotypes, each adapted to a different combination of light and temperature. In her lab's growth chambers, they are easy to tell apart: Some are bright green, whereas others have a yellowish hue. Each makes a different light-absorbing pigment so that at its particular depth, "it is the most efficient photosynthetic machine," Chisholm says.

When the U.S. Department of Energy's Joint Genome Institute first began sequencing microbes in 2003, Chisholm convinced it to sequence two Prochlorococcus strains-this at a time when sequencing a single microbe was a big deal-so she could assess genetic differences between the forms adapted to low and high light levels. "That was very greedy of me," she smiles. Her team found the high light-adapted ecotype's genome was very streamlined-1.7 million bases with just 1700 genes. "It's one of, if not the, simplest self-sustaining organism we know of," says Chisholm's postdoc Jamie Becker. The low-light version's genome has 2.4 million bases, with 2275 genes, including some that may enable the microbe to work best in low light and avoid damage from the sun should it wind up at the surface somehow.

As new molecular technologies arose-microarrays that document gene activity and proteomics methods that look at the proteins present, for example-Chisholm and her students and postdocs were quick to learn and apply them. She credits them for all her successes. "When I say 'we' I mean 'they,'" she remarked at a lecture on her life's work. When undergraduate Jed Fuhrman worked in her lab and contributed to a paper published in Nature, "she had no trouble just handing off the first authorship even though she was a new professor" and wrote most of the paper, he recalls. (Fuhrman is now a biological oceanographer at the University of Southern California in Los Angeles.)

Together, her lab found that each of the main Prochlorococcus ecotypes has its own genomic "island," a patch of genes that confers specific adaptations to an environment. One island helps the microbe survive in very low-phosphorus waters, for example. Bacteriophages, viruses that infect bacteria and can either pick up or deposit genetic material, may move these islands and other genes between ecotypes, Chisholm's postdoc Debbie Lindell proposed in 2004, thereby ensuring the microbes can adapt to changing conditions.

Chisholm's lab remained small until about 15 years ago, when the mounting evidence that ocean microbes are major players in the biosphere persuaded three foundations-Seaver, Gordon and Betty Moore, and Simons-to pour millions into studying them. The lab grew from a handful of researchers to dozens, who not only could spend weeks at sea, sampling and collecting data, but could also return to the lab to try innovative ways of probing how the microbe worked. "That's when everything got exciting," Chisholm says.

The worldwide sampling showed that the five primary ecotypes didn't begin to capture Prochlorococcus's diversity. Sequencing revealed hundreds of strains coexisting even in just a milliliter of seawater, each with more than 100 distinctive genes. And when it became possible to sequence genomes from single cells-a technique Chisholm's lab pioneered for marine microbes- each strain turned out to encompass still more genetic variation. "It's not one bug, it's a whole family of things that grade into each other," says Olson, now at WHOI.

Although each cell has only about 2000 genes, Prochlorococcus as a whole has a "pan-genome" of perhaps 80,000 genes, Chisholm and her colleagues estimate. "That's a ton of information for these little guys," she says, and it must be the secret of Prochlorococcus's success. Its enormous genomic repertoire enables it to cope with conditions across a vast swath of the oceans, dominating warm seas from 40° North to 40° South (see map, below).

The sea's invisible pasture

Drawing on ocean and marine microbe data collected by Massachusetts Institute of Technology researchers, this model depicts the most dominant types of phytoplankton in the world's oceans, with Prochlorococcus ruling much of the globe and bigger diatoms dominating nearer the poles.

These waters contain an estimated 3 billion billion billion Prochlorococcus cells, collectively weighing as much as 220 million Volkswagen Beetles. That abundance makes the microbe a heavyweight in ocean food webs and climate. It is a key source of food in the nutrient-poor regions of the ocean where it flourishes, Becker says. " Prochlorococcus makes organic matter that other microorganisms eat." And because of its role in the carbon cycle, the microbe significantly regulates levels of climate-warming carbon dioxide (CO ₂), Chisholm says.

Yet Chisholm is uncomfortable with proposals to stem global warming by manipulating the ocean's life to capture more CO ₂. In 2001, she vigorously spoke out against proposals to fertilize the oceans with iron to stimulate phytoplankton growth, coauthoring a paper in Science that warned of possible unforeseen consequences. Years later, in 2012, she publicly debated the Dalai Lama's "let's try it" position when the two were on a panel at MIT.

Despite her current visibility, Chisholm still feels much of the insecurity that burdened her early in her career. When she was named an Institute Professor, for example, she wondered, "How could this be?" she recalls. "I don't feel like that kind of person."

A sense of being an imposter, she admits, continues to dog her. She still works long hours-"I could never juggle [so] many things," Coe says. "But the older she gets the more worried she gets." In 2013, Chisholm's anxiety about the lab and the future of her Prochlorococcus cultures if she retires was so palpable she began to develop minor health problems. Starting tai chi lessons gave her a new perspective. "I needed to do something to get me out of my head," she recalls. She has also found an outlet, with artist and author Molly Bang, writing children's science books, featuring the sun as the narrator. One tells the story of the "invisible pasture of the sea."

She continues to be driven to unravel the story of Prochlorococcus. In 2014, for example, electron micrographs taken in her lab revealed tiny vesicles budding off Prochlorococcus cells; later, her postdoc Steven Biller showed that each cell releases two to five lipid-membrane bubbles filled with DNA and RNA per generation-possible food sources for other plankton, decoys for viruses, gene-transfer vehicles, or even messengers that communicate with other microbes. Biller has since found that other marine bacteria make these vesicles as well. "This was a whole new feature of the ocean ecosystem," Chisholm says.

In another hint that Prochlorococcus builds extensive partnerships with other marine microbes, Chisholm's lab found that it secretes a broad variety of peptides, or short protein fragments, that in other organisms have antimicrobial or signaling activity. Prochlorococcus has as many as 1500 different peptides per cell, according to work by Andres Fernando Cubillos-Ruiz, now a postdoc at MIT in another lab. The peptides appear to provide food for other very abundant ocean microbes and some of those in turn secrete an enzyme that detoxifies reactive oxygen molecules. Prochlorococcus doesn't make that enzyme itself but may be able to take it in from the surrounding water. The peptides may also signal other microbes in the surrounding waters-although what messages they carry is unclear. "I continue to be humbled by the major things we learn from Prochlorococcus that change the way we think about oceans," Chisholm says.

The tiny, mighty bacterium could also change thinking about life on land. Chisholm's postdoc Rogier Braakman has pieced together Prochlorococcus's evolutionary history, drawing on the genes active in different ecotypes and the conditions in which they live. Braakman is examining whether the microbe's metabolic activity hundreds of millions of years ago could have helped pave the way for life to explode outside of the oceans by drawing down atmospheric carbon dioxide and increasing oxygen in the air. This scenario has plenty of questions, Chisholm says, but its potential importance "makes it worth spending the time to connect the dots."

At 68, she is eager to keep making those connections. "I should probably be thinking about retiring, but I'm not because Prochlorococcus is too darn interesting," Chisholm says. "I'm really very grateful to have this organism in my life."

doi:10.1126/science.aal0873

Liz is a senior correspondent covering many aspects of biology for Science.

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SAN FRANCISCO, Calif. - Marisa Trego is trying to solve a riddle. The marine biologist wants to find long-lasting ocean pollutants that no one knows about - yet. They could be toxic, causing health problems in wildlife and people. She studies dolphins to find clues about these pollutants. But when you don't know what you're looking for, how can you find it? Trego's solution: Look in fat.

When she did, using a new approach, she found more than 30 percent of the test samples held pollutants that no one could name.

Trego works at the Conservation Ecology Lab at San Diego State University in California. She reported her team's early findings on December 14, at the Society for Marine Mammalogy meeting in San Francisco.

Her team has been studying insulating fatty tissue, known as blubber. It's what keeps most marine mammals warm. Many long-lived - or persistent - pollutants tend to accumulate in fat (whether that fat is in a whale, a dolphin, an insect or a person). And the longer an animal lives, the longer its fat has to pick up these pollutants. This buildup is called bioaccumulation. That's why scientists often test small samples of blubber for specific chemicals, such as DDT (an insect-killing chemical that was banned most places years ago).

But probing samples for what you think they may contain - or what's easy to measure - isn't always helpful, says Trego. It "doesn't really give you the whole picture" of what pollutants may be there, she explains. So she uses a combination of tests. These don't look for particular chemicals. "This newer method lets the sample tell you what's in it," she explains.

Trego collected blubber samples from 10 short-beaked common dolphins ( Delphinus delphis). Then she used the new tests to analyze what was in the fat. She's especially interested in finding pollutants known as halogenated (HAY-lo-jen-ait-ed) compounds, or HOCs. Chemicals that include halogens are known for lasting a long time and building up in fat. HOCs also are very likely to be toxic.

Eunha Hoh is a scientist at San Diego State University in California. She focuses on environmental health issues. And she developed the new method that Trego's team has just used.

Hoh took small pieces of blubber from bottlenose dolphins ( Tursiops truncatus) and analyzed them using two different instruments. Each sample generated up to 10,000 chemical "fingerprints." These were the distinct signatures of different compounds. Then, Hoh picked out the fingerprints that shared some similarities to known HOCs. With a shorter list of about 100 to 200 "suspects," she worked on finding the true identity of the pollutants in the blubber.

Getting an ID was like trying to catch a criminal by searching police records for matching human fingerprints. To find matches for unknown compounds, Hoh looked through databases of chemical "fingerprints." Some pollutants have no fingerprints on file. Those "suspects" may stay listed as unknown for a little longer.

One of Trego's goals is to speed up this fingerprint-matching process. So far, Hoh has compiled a library of 327 known chemicals. Using that library, Trego identified 7 out of every 10 of the compounds in her samples. These included DDT and other insecticides. Still, many compounds remain unidentified. "That shows we have a lot more to learn," Trego says. If she can add new IDs to the library, that will help other researchers, too.

Unhealthy connections

Trego doesn't just want to know what's in an animal's blubber, but also whether it may pose a risk to its health. As a first step, she's tested the dolphin blubber samples for two hormones: cortisol (KOR-tih-saal) and testosterone. Cortisol is a hormone that climbs when an animal is stressed. Testosterone is a hormone that can serve as a clue to an animal's reproductive health. Next, she'll look for links between the amount of these hormones and the levels of certain pollutants in blubber.

Later, Trego will study skin samples. From those, she hopes to coax out the DNA to see which genes were turned "on" or "off" at the time the sample was collected. These patterns, too, can provide clues to an animal's health.

"Putting all these things together will give us a big picture of what's going on with the dolphins," says Trego. Their overall health is important. If there are toxic pollutants in the sea, these can act as sentinels. That means that these animals can point to possible health risks in other animals, including people.

"We have a lot of new technologies. Using them just to find new pollutants isn't enough," says Karen Acevedo-Whitehouse. She is a veterinarian who works with marine mammals at the Autonomous University of Queretaro, in Mexico. "We need to link these findings to the health of oceans, animals and people," she explains. "Without that connection, none of it makes sense."

Power Words

(for more about Power Words, click here)

bioaccumulation A term for the body's process of picking up substances (usually from the environment) and then storing them within tissues (such as fat) in ever-growing quantities.

blubber The thick layer of fat under a marine mammal's skin that helps it stay warm even in cold waters. In the past, whalers would boil whale blubber to extract oil, which had many industrial uses.

compound (often used as a synonym for chemical) A compound is a substance formed from two or more chemical elements united in fixed proportions. For example, water is a compound made of two hydrogen atoms bonded to one oxygen atom. Its chemical symbol is H ₂ O.

contaminant Pollutant; a chemical, biological or other substance that is unwanted or unnatural in an environment such as water, soil, air, or food. Some contaminants may be harmful in the amounts at which they occur or if they are allowed to build up in the body over time.

cortisol A stress hormone that helps release glucose into the blood in preparation for the fight or flight response.

DDT (short for dichlorodiphenyltrichloroethane) This toxic chemical was for a time widely used as an insect-killing agent. It proved so effective that Swiss chemist Paul Müller received the 1948 Nobel Prize (for physiology or medicine) just eight years after establishing the chemical's incredible effectiveness in killing bugs. But many developed countries, including the United States, eventually banned its use for its poisoning of non-targeted wildlife, such as birds.

DNA (short for deoxyribonucleic acid) A long, double-stranded and spiral-shaped molecule inside most living cells that carries genetic instructions. It is built on a backbone of phosphorus, oxygen, and carbon atoms.In all living things, from plants and animals to microbes, these instructions tell cells which molecules to make.

environmental health A research field that focuses on measuring the effects of pollutants and other factors in the environment on the health of people, wildlife or ecosystems.

gene A segment of DNA that codes, or holds instructions, for producing a protein. Offspring inherit genes from their parents. Genes influence how an organism looks and behaves.

halogen An element from a row on the periodic table that includes fluorine, chlorine, bromine, iodine and astatine. These nonmetallic elements are reactive, so they combine with hydrogen to form strong acids. Compounds made with these elements are often referred to as halogenated. They also may resist breakdown in the environment. Such chemicals are referred to as persistent.

halogenated organic compounds (HOCs) Carbon-based compounds that contain one (or more) of the five elements in the halogen group: fluorine, chlorine, bromine, iodine, or astatine. Many are toxic because these compounds are very reactive. That is, HOCs quickly combine with other chemicals to form new - and usually harmful - compounds. HOCs are used in medicines, plastics, paint, cars and flame-resistant coatings. They last in the environment for a long time. And if those compounds are toxic, that can be a bad thing. Consider DDT (dichlorodiphenyltrichloroethane). The United States banned this insecticide in 1972 because of its poisonous effects on animals and people - and the fact that it resisted breakdown once it got into the environment (thereby persisting for decades). It's important to note that not all HOCs are bad. Marine algae also make these compounds. Scientists aren't yet sure if the natural compounds can be toxic, too.

hormone (in zoology and medicine) A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body.

insecticide A substance used to kill insects.

marine biology The field of science that deals with studying creatures that live in ocean water, from bacteria and shellfish to kelp and whales. A person who works in this field is called a marine biologist.

persistent An adjective for something that is long-lasting.

pesticide A chemical or mix of compounds used to kill insects, rodents or other organisms harmful to cultivated plants, pet or livestock, or unwanted organisms that infest homes, offices, farm buildings and other protected structures.

pollutant A substance that taints something - such as the air, water, our bodies or products. Some pollutants are chemicals, such as pesticides. Others may be radiation, including excess heat or light. Even weeds and other invasive species can be considered a type of biological pollution.

polychlorinated biphenyls (or PCBs) A family of 209 chlorine-based compounds with a similar chemical structure. They were used for many decades as a nonflammable fluid for insulating electrical transforms. Some companies also used them in making certain hydraulic fluids, lubricants and inks. Their production has been banned in North America and many countries throughout the world since around 1980.

sentinel A guard or something that watches over others, or that effectively offers some warning of a potential problem.

testosterone Although known as a male sex hormone, females make this reproductive hormone as well (generally in smaller quantities). It gets its name from a combination of testis (the primary organ that makes it in males) and sterol, a term for some hormones. High concentrations of this hormone contribute to the greater size, musculature and aggressiveness typical of the males in many species (including humans).

toxic Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.

veterinary Having to do with animal health. A doctor who specializes in treating animals is a veterinarian.

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Using dolphins to find unknown ocean pollutants

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SAN FRANCISCO, Calif. - Marisa Trego is trying to solve a riddle. The marine biologist wants to find long-lasting ocean pollutants that no one knows about - yet. They could be toxic, causing health problems in wildlife and people. She studies dolphins to find clues about these pollutants.

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DRYDEN, ONT.-The Star and volunteers from an environmental group have found mercury-contaminated soil upstream from Grassy Narrows First Nation.

Over several weeks this past fall, first the volunteers from Earthroots and then reporters from the Star dug a dozen holes and took soil samples from a site behind an old paper mill, then had them analyzed by a lab. Soil from three holes contained significantly higher-than-normal levels of mercury.

"There is more than enough of a smoking gun to require a full investigation," said Gord Miller, Ontario's former environmental commissioner and the chair of the Earthroots group.

When presented with the findings, the province told the Star it takes them "seriously" and will work with the current landowner to determine if more tests are needed.

Mercury contamination, a serious health risk, has plagued the indigenous community in northern Ontario for decades. Dangerous and persistently high levels of mercury in the sediment and fish in the river system suggest there is an ongoing source, but the province has denied the possibility that the site of the old mill - 100 kilometres upstream from Grassy Narrows - could be responsible.

The samples were taken from an area circled on a map by retired mill worker Kas Glowacki, who said that in 1972 he was part of a group who "haphazardly" dumped drums filled with salt and mercury into a pit behind the mill.

Persistently high levels of mercury in the sediment and fish of the Wabigoon River system - which the Grassy Narrows community has long relied on - suggest there is an ongoing source of contamination. (Todd Korol / Toronto Star file photo)

Test results from three holes came back showing elevated levels of mercury - up to nearly 80 times the level expected to be found in soil from that region of the province.

Two leading scientists say the results are a clear sign of industrial mercury contamination.

"It's definitely industrial mercury," said scientist John Rudd when presented with the Star's findings. "I think it is significant."

Rudd and another mercury expert, Western University professor Brian Branfireun, say a fuller investigation including more testing would help determine whether this mercury was spilled on the ground, if it is flowing sideways through groundwater or if it is moving up from a source below.

"Until then, all these questions will remain," said Rudd, who has studied the issue of mercury contamination in the area for decades.

Neither scientist was involved in collecting the soil samples.

The contaminated samples do not prove the existence of the alleged dump site but are enough to warrant further attention from professionals, said Miller, whose organization has acted as an adviser to and advocate for Grassy Narrows.

"We have an allegation of an improper disposal of this material. We've gone in and done some preliminary sampling. We found some anomalies," Miller said, adding the province's previous barrel search was "not good enough," and that a "full and thorough investigation" should be done over a large area.

Late last year, Ontario's environment minister announced the province had searched for the barrels in the summer and concluded they did not exist. The government searched a different area than that subsequently sampled by Earthroots and the Star. The province conducted metal-detecting tests, and also said it did groundwater tests in the area, though no soil was tested.

Before that search, an Earthroots representative said he asked the province to search in a larger area, which did not happen. A request from Grassy Narrows to the pulp and paper company that now owns the site, Domtar, for access to the land to conduct a search by its own team of experts was denied, according to correspondence obtained by the Star.

Between 1962 and 1970, the former paper mill - then owned by Reed Paper - dumped 10 tonnes of mercury into the Wabigoon River, contaminating the fish and sickening generations who consider walleye a dietary staple. Physical symptoms of mercury poisoning include loss of muscle co-ordination and tunnel vision. Fetuses are particularly vulnerable to cognitive damage, according to recent research.

Today, the walleye near Grassy Narrows are the most mercury-contaminated in the province. And recent studies conducted by Japanese experts found that 90 per cent of the people tested in Grassy Narrows and the nearby Whitedog First Nation have a symptom of mercury poisoning.

It was a government-funded scientific report commissioned by Grassy Narrows and released in May that said the persistently high levels of mercury suggest the metal is still being released into the river system. The source needs to be found and stopped, the report says.

Rudd - one of the authors of that report, who is currently working with Grassy Narrows and has received provincial funding to measure mercury contamination in the Wabigoon River system - said the entire area around the old paper processing plant should be examined because historically these types of plants have been known to be sources of contamination long after they stopped using mercury in the paper-bleaching process.

Mercury has not been used in paper production at the site in decades, and there is no suggestion that Domtar, several owners removed from Reed Paper, is responsible for any possible ongoing source of mercury.

Regardless of whether the barrels exist, Rudd said that he believes an investigation of the area would "find mercury in several locations."

Rudd has in the past worked on two major industrial mercury remediation projects, including at the site of a former plant on the Penobscot River in Maine. A U.S. Federal Court ordered a study of mercury contamination in the area and then a cleanup plan.

Rudd worked at the Maine site for more than seven years and said there were several locations of mercury contamination, including under the factory area where mercury was used in production, dump sites where mercury-contaminated machinery was disposed of, and other "spill" areas where mercury moved around the facility.

Retired mill worker Kas Glowacki told the Star that in 1972 he was part of a group who dumped drums filled with salt and mercury into a pit behind the paper mill. (Jayme Poisson/Toronto Star file photo)

As part of its ongoing investigation into the mercury poisoning of Grassy Narrows First Nation residents, the Star travelled on Nov. 12 to the area identified by former mill worker Glowacki because, weeks prior, volunteers from Earthroots said they'd found a spot with a significant level of mercury in the soil. The Star wanted to take its own samples, so reporters went to the area with Earthroots volunteers.

A Domtar spokesperson did not answer several questions about the soil samples, directing the Star to the province's Environment Ministry. "We were surprised to learn that the Toronto Star entered and disturbed private property without permission. We ask that you respect our rights and avoid a trespass situation in the future," said Domtar's David Struhs, vice-president, corporate services and sustainability.

The clearing - which measures about 30 metres across - is near a public road but behind a tree line. Cars, trucks and the occasional dog walker pass along nearby Gordon Rd.

The tops of some of Domtar's largest factory buildings can be seen about a kilometre to the east. The Wabigoon River flows just on the other side and at the foot of these buildings.

Star reporter David Bruser digs for soil samples on a site about 100 kilometres upstream from Grassy Narrows First Nation. (Jayme Poisson/TORONTO STAR)

The Star and Earthroots dug 12 holes and bagged soil samples from varying depths - generally between surface level a depth of 60 to 76 centimetres. The freezer bags containing the wet soil were sent to a lab for testing.

The soil from the three contaminated holes, tested by an independent and accredited Western University lab that specializes in mercury, showed levels of more than 1,000 parts per billion. One sample came back at nearly 4,000 parts per billion.

Citing previously published research conducted in the same area of Ontario, Branfireun said that soil mercury concentrations would normally be 100 to 200 parts per billion near the surface and about 40 to 50 parts per billion in the sands and clays underground. Branfireun holds a Canada Research Chair in Environment and Sustainability.

In the area sampled by Earthroots and the Star, soil from six uncontaminated holes came back even lower - under 20 parts per billion.

"You don't just show up in the middle of the bush and dig a hole and just find those mercury levels in a hole," said Branfireun, who is the director of the accredited lab but did not participate in the testing or analysis of the samples. "There's no way that it could ever be argued that through any natural process there could be that much mercury in the environment in that location. It's impossible."

Where the mercury came from is unclear.

Branfireun noted that in one of the holes where the contaminated soil was found, the mercury readings increased with depth - which suggests the mercury could possibly be coming from below or travelling horizontally. But it's impossible to say for certain at this point.

In another hole, the readings decreased with depth. Rudd, citing his previous experience in Maine, said that mercury could have also been spilled on the ground from above.

"If it's been spilled here or there over the years, unless the soil moves, most of it (mercury) attaches to the soil particles," he said.

The Star travelled to a spot near the old paper mill in Dryden, Ont., to collect soil samples. (Jayme Poisson/TORONTO STAR)

In addition, scientists told the Star that groundwater flows can transport mercury sideways, up and down.

"A complete groundwater study needs to be done and then you can tell which way the water is flowing and how much mercury is being transported," Rudd added.

The province's July search for the alleged barrels relied in part on an oblique aerial photo of the mill property the Star had initially provided to retired mill worker Glowacki. He circled the area he thought was the most likely to be the spot where the barrel dump occurred.

"We ... found there are no barrels buried and there is no source," Environment Minister Glen Murray said in the legislature in November.

The province searched to the east of Gordon Rd., a report on the search said.

Earlier in the summer, before the search, Earthroots' David Sone said that after speaking with Glowacki about the barrels, he told the province during a conference call he thought they should search west of Gordon Rd. as well, but was ignored. Weeks later, he found a clearer aerial image of the terrain and had Glowacki circle this map, too. He circled west of Gordon Rd.

This is why in October volunteers from his organization went to that second spot circled by Glowacki to investigate, Sone said.

For Earthroots, it was relatively easy and cheap to find soil contaminated with mercury - $970 for travel expenses and equipment, including a GPS - and, Sone said, it was another frustrating example of the provincial government's lack of political will to address the mercury problem in Grassy Narrows.

"Would the government treat toxic threats like this so negligently if they were in Toronto?" Sone asked. "Ontario has consistently looked the other way and refused to make things right, even in the face of ever mounting evidence that there is an ongoing health and environmental crisis unfolding on their watch."

An Environment Ministry spokesperson said this week the government will again contact Glowacki to get more information on the area behind the mill.

Jayme Poisson can be reached at 416-814-2725. David Bruser can be reached at 416-869-4282.

The Toronto Star and thestar.com, each property of Toronto Star Newspapers Limited, One Yonge Street, 4th Floor, Toronto, ON, M5E 1E6. You can unsubscribe at any time. Please or see our for more information.

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Mercury-tainted soil found upstream from Grassy Narrows First Nation | The Star

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DRYDEN, ONT.-The Star and volunteers from an environmental group have found mercury-contaminated soil upstream from Grassy Narrows First Nation. Over several weeks this past fall, first the volunteers from Earthroots and then reporters from the Star dug a dozen holes and took soil samples from a site behind an old paper mill, then had them analyzed by a lab.

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Some call it a doorway to hell. Or a portal to the underworld. Scientists call it a crater. But everyone agrees that it's getting bigger.

The Batagiaka crater in eastern Siberia, already the largest of its kind, has been growing wider. The most recent measurements, published in February of this year, estimate the crater to be 0.6 miles long and 282 feet deep. These numbers are expected to continue gradually increasing.

The local Yukatian people approach the area with caution. They report hearing ominous noises, leading some to call it a portal to the underworld. For scientists, however, the crater offers a more Earthly fascination.

Siberia's crater is caused by melting permafrost, perennially frozen soil that remains in that state for at least two consecutive years. The resulting irregular terrain of mounds and hollows is called thermokarst.

A new study published in the journal Quaternary Research indicates that the crater may allow scientists to view more than 200,000 years of climate change in Siberia. Scientists plan to collect sediment to analyze how the landscape changed as climate warmed and cooled during the last Ice Age. This could provide insights for today's climate change issues. Satellite imagery indicates that the crater expands, on average, by 33 feet per year.

Melting began in the 1960s, spurred by rapid deforestation due to development As trees that shaded the frozen soil were removed, the sun began warming the soil, causing the ice to melt. The formation of the hole has accelerated further in recent years as the planet has warmed steadily, spurred by rising greenhouse gases.

Eroding and melting soil cause a phenomena that is often known as " drunken trees," in which trees cannot grow straight, further reducing the amount of shade covering the ground. This process is happening across parts of the entire north, from Alaska to Eurasia.

As layers of deep sediment rapidly melt, it can cause the top layer of soil to slump downward, causing massive craters that damage pipelines, crack pavement, and even swallow houses whole.

Increasing thermokarst is not only one result of a warming climate, but it may also be a cause of warming temperatures in the future. Scientist estimate that as much as 50 percent of the Earth's methane gas may be stored in Arctic and Northern Hemisphere permafrost (methane is a greenhouse gas more powerful than carbon dioxide).

A 2016 study in the journal Nature Communications looked at greenhouse gases released from Siberian permafrost in the last ice age and found that the climate experienced a significant spike in temperatures from this alone. A spike, they believe, that could happen again.

"The Arctic carbon reservoir locked in the Siberian permafrost has the potential to lead to massive emissions of the greenhouse gases carbon dioxide and methane to the atmosphere," the study's co-author Francesco Muschitiello told Columbia University's science blog after the study's release.

The Batagiaka crater may be Siberia's biggest but it's not its only permafrost-induced crater. Dozens were found in the country as recently as 2015.

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Siberia's Growing 'Doorway to Hell' Offers Clues on Climate Change

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Some call it a doorway to hell. Or a portal to the underworld. Scientists call it a crater. But everyone agrees that it's getting bigger. The Batagiaka crater in eastern Siberia, already the largest of its kind, has been growing wider.

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CC BY-NC 2.0 dotun55

Nature has a great way of balancing itself out, but when us humans get involved, we tend to throw things out of whack. Forests and oceans are natural carbon sinks that absorb carbon dioxide from the atmosphere, but since we've been pumping too much into the air, those sinks can't keep up.

Scientists at the Max Planck Institute in Germany, led by biologist Tobias Erb, have figured out a way to supercharge plants to make them better at absorbing CO2, which could be a key defense against climate change.

Erb and his team figured out a way to make plants more efficient at absorbing carbon, so that they consumed more carbon in a shorter amount of time.

"If you think about plants, they're efficient CO2-fixing filters, but they are not fast," Erb said. "I think there is a chance to improve existing biology with synthetic biology."

Erb's team identified 17 enzymes from nine different organisms, re-engineering three of them, that had an amped up carbon consumption. When those enzymes worked together as a team, they surpassed not only plants' natural enzymes when it can to carbon consumption, but also themselves individually.

Existing enzymes in plants consume about 5 to 10 molecules of CO2 per second. The team of enzymes that Erb used consumed 80 molecules per second.

So far, these enzymes have only been tested in test tubes in the lab, but the next step is real world testing where the enzymes would be introduced into plants to see if the same result occurs. If those tests show that plants really can be supercharged, we could have a new tool in the fight against climate change where not only do we protect the amazing carbon-absorbing forests we have, but we also add these super plants or an artificial leaf technology using the enzymes into the mix.

You can watch a video of Erb explaining the enzymes below.

Please enable JavaScript to view the comments.

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Plants could be supercharged to absorb more carbon dioxide

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Nature has a great way of balancing itself out, but when us humans get involved, we tend to throw things out of whack. Forests and oceans are natural carbon sinks that absorb carbon dioxide from the atmosphere, but since we've been pumping too much into the air, those sinks can't keep up.

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Información relacionada disponible en español
Nutrient pollution is one of America's most widespread, costly and challenging environmental problems, and is caused by excess nitrogen and phosphorus in the air and water.

Nitrogen and phosphorus are nutrients that are natural parts of aquatic ecosystems. Nitrogen is also the most abundant element in the air we breathe. Nitrogen and phosphorus support the growth of algae and aquatic plants, which provide food and habitat for fish, shellfish and smaller organisms that live in water.

But when too much nitrogen and phosphorus enter the environment - usually from a wide range of human activities - the air and water can become polluted. Nutrient pollution has impacted many streams, rivers, lakes, bays and coastal waters for the past several decades, resulting in serious environmental and human health issues, and impacting the economy.

Too much nitrogen and phosphorus in the water causes algae to grow faster than ecosystems can handle. Significant increases in algae harm water quality, food resources and habitats, and decrease the oxygen that fish and other aquatic life need to survive. Large growths of algae are called algal blooms and they can severely reduce or eliminate oxygen in the water, leading to illnesses in fish and the death of large numbers of fish. Some algal blooms are harmful to humans because they produce elevated toxins and bacterial growth that can make people sick if they come into contact with polluted water, consume tainted fish or shellfish, or drink contaminated water.

Nutrient pollution in ground water - which millions of people in the United States use as their drinking water source - can be harmful, even at low levels. Infants are vulnerable to a nitrogen-based compound called nitrates in drinking water. Excess nitrogen in the atmosphere can produce pollutants such as ammonia and ozone, which can impair our ability to breathe, limit visibility and alter plant growth. When excess nitrogen comes back to earth from the atmosphere, it can harm the health of forests, soils and waterways.

To learn more, read about the sources and solutions or explore an educational module on nutrient pollution.

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information management > web site & services

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pollutants & contaminants > biological contaminants > algae

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The Problem - Too much nitrogen and phosphorus in lakes, rivers, streams and coasts results in serious environmental, economic, and health effects.

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Fighting big farm pollution with a tiny plant

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Fertilizer runoff can fuel the growth of toxic algae nearby lakes. A teen decided to harness a tiny plant to sop up that fertilizer.

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LUSI 3D Animation Russian Institute of Geological Studies

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Sidoarjo Mudflow Disaster - Java, Indonesia

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http://www.furiousearth.com A drilling operation that went horribly wrong triggered a mud volcano that buried several villages in hot, sulphurous mud, creating an environmental disaster. The site was visited by George Kourounis and the Angry Planet television series team. Produced by: www.peterrowe.tv

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Fifty years after a Dryden pulp mill dumped its effluent into a northern Ontario watershed, mercury continues to rise in some lakes, according to a study commissioned by the provincial government and the Grassy Narrows First Nation.

The report released Monday also reveals how little is known about the environmental and health consequences of the mercury that flowed freely into the English-Wabigoon water system between 1962 and 1970.

The research review of human and ecological health in Grassy Narrows was conducted by fresh water scientist Patricia Sellers. It takes a wide-ranging look at all published research into the contamination and mercury poisoning of people at Grassy Narrows.

"We have bits and pieces, small amounts of data here and there throughout the years of the human health in Grassy Narrows and various health issues and an assessment of initiatives to address those health issues," Sellers said. "But there hasn't been anything very comprehensive."

People in Grassy Narrows continue to suffer the effects of mercury poisoning, exhibiting symptoms such as loss of motor function, tingling and weakness in limbs, difficulty speaking and swallowing.

"We know little about the effects of low-dose exposure [to mercury] over the long-term," Sellers wrote in the report.

Residents believe developmental delays and physical abnormalities in children are also related to the contamination, but Sellers says no studies have been conducted in Grassy Narrows on the effects of pre-natal exposure to mercury.

Surface contamination rising

Mercury levels in sediment in Clay Lake and parts of the Wabigoon River are twice the Canadian threshold for remediation and are on the rise in other area lakes where the people of Grassy Narrows continue to catch and eat fish, the report says.

"Staggering levels of mercury" are buried deep in the sediment at Clay Lake, which acts as a sort of settling pond for the contaminants, Sellers said. But sites downstream of the lake show a trend of increasing surface sediment.

Three recommendations for remediation of the river system were proposed 30 years ago and ignored, Sellers said, meaning only "natural recovery" has been underway since 1970.

"Earlier predictions that natural recovery alone would mean sustained levels [of mercury] in fish for decades have been realized," Sellers said.

The report's 40 recommendations include:

Conduct comprehensive health and diet surveys at Grassy Narrows to see the effects of eating fish on health, including the impact on child development and aging-related neurodegenerative diseases. (The most recent Health Canada studies are 20 years old.)

A comprehensive discussion about remediation of the Wabigoon River that includes Grassy Narrows First Nation.

Examine the effects of logging on the mercury load in the area and investigate whether any effluent continues to flow into the river from the Dryden mill.

Review and evaluate existing guidelines for fish consumption and ensure they are communicated to community members in a culturally appropriate way.

Long-term monitoring of the mercury levels in all lakes that are popular among Grassy Narrows families for subsistence fishing.

Establish a community-based research station to co-ordinate all 40 recommendations in the report.

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Mercury levels still rising near Grassy Narrows First Nation | CBC News

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Fifty years after a Dryden pulp mill dumped its effluent into a northern Ontario watershed, mercury continues rise in some lakes, according to a study that also reveals little is known about the continuing health consequences of the contamination on the people at Grassy Narrows First Nation.