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How do complex biological structures -- an eye, a hand, a brain -- emerge from a single fertilized egg? This is the fundamental question of developmental biology, and a mystery still being grappled with by scientists who hope to one day apply the same principles to heal damaged tissues or regrow ailing organs.

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How do complex biological structures -- an eye, a hand, a brain -- emerge from a single fertilized egg? This is the fundamental question of developmental biology, and a mystery still being grappled with by scientists who hope to one day apply the same principles to heal damaged tissues or regrow ailing organs.

Now, in a study published May 31, 2018 in Science, researchers have demonstrated the ability to program groups of individual cells to self-organize into multi-layered structures reminiscent of simple organisms or the first stages of embryonic development.

"What is amazing about biology is that DNA allows all the instructions required to build an elephant to be packed within a tiny embryo," said study senior author Wendell Lim, PhD, chair and Byers Distinguished Professor in the Department of Cellular and Molecular Pharmacology at UCSF, director of the NIH-funded Center for Systems and Synthetic Biology, and co-director of the National Science Foundation-funded Center for Cellular Construction. "DNA encodes an algorithm for growing the organism -- a series of instructions that unfolds in time in a way we still don't really understand. It's easy to get overwhelmed by the complexity of natural systems, so here we set out to understand the minimal set of rules for programming cells to self-assemble into multicellular structures."

A critical part of development is that, as biological structures form, cells communicate with one another and make coordinated, collective decisions about how to structurally organize themselves. To mimic this process, the new research -- led by UCSF postdoctoral researcher Satoshi Toda, PhD, in Lim's lab -- relied on a powerfully customizable synthetic signaling molecule called synNotch (for "synthetic Notch receptor") recently developed in Lim's lab, which allowed the researchers to program cells to respond to specific cell-cell communication signals with bespoke genetic programs.

For example, using synNotch, the researchers engineered cells to respond to specific signals from neighboring cells by producing Velcro-like adhesion molecules called cadherins as well as fluorescent marker proteins. Remarkably, just a few simple forms of collective cell communication were sufficient to cause ensembles of cells to change color and self-organize into multi-layered structures akin to simple organisms or developing tissues.

In their simplest experiment of this sort, the researchers programmed two groups of cells to self-organize into a two-layered sphere. They started with one group of blue cells expressing a signaling protein on their surfaces, and a second group of colorless cells sporting a custom synNotch receptor programmed to detect this signal protein. When isolated from one another, these cell populations did nothing, but when the two groups were mixed, the blue cells activated the synNotch receptors on the clear cells and triggered them to produce sticky cadherins and a green marker protein called GFP. As a result, the colorless cells quickly began to turn green and cluster together, forming a central core surrounded by an outer layer of their partner blue cells.

The researchers went on to program groups of cells to self-assemble in increasingly complex ways, such as building three-layered spheres or starting with a single group of cells that sorted themselves into two distinct groups before forming a layered sphere. They even engineered cells that formed the beginnings of "polarity" -- the distinct front-back, left-right, head-toe axes that define the "body plans" of many multicellular organisms -- by expressing different types of cadherin adhesion molecules that instructed the cellular assemblages to divide into "head" and "tail" sections or to produce four distinct radial "arms."

These more complex cellular programming feats demonstrated that simple starter cells could be programmed to develop over time to form more complex structures, much like a single fertilized egg divides and differentiates to form different parts of the body and distinct tissues like skin, muscle, nerve, and bone. Lim's team showed that these complex spheroids were also self-repairing: when the researchers cut the multi-layered spheroids in half with a micro-guillotine developed by co-authors Lucas R. Blauch and Sindy Tang, PhD, of Stanford University, the remaining cells quickly re-formed and reorganized themselves according to their intrinsic program.

SynNotch was originally developed in the Lim lab by co-author Kole Roybal, PhD, now an assistant professor of microbiology and immunology at UCSF, and Leonardo Morsut, PhD, now an assistant professor of stem cell biology and regenerative medicine at the University of Southern California and co-corresponding author on the new paper.

In the future, Lim imagines programming ever more complex tissue-like cellular structures through multiple layers of synNotch signaling. For example, activation of one synNotch receptor by cell-cell contact or chemical signaling could trigger cells to produce additional distinct synNotch receptors, leading to a cascade of engineered signaling steps. In this way, Lim envisions programming the self-organization of the elaborate structures that would eventually be needed for growing tissues for wound repair or transplant.

"People talk about 3D-printing organs, but that is really quite different from how biology builds tissues. Imagine if you had to build a human by meticulously placing every cell just where it needs to be and gluing it in place," said Lim, who is a Howard Hughes Medical Institute investigator and member of the UCSF Helen Diller Family Comprehensive Cancer Center. "It's equally hard to imagine how you would print a complete organ, then make sure it was hooked up properly to the bloodstream and the rest of the body. The beauty of self-organizing systems is that they are autonomous and compactly encoded. You put in one or a few cells, and they grow and organize, taking care of the microscopic details themselves."

Lim says he hopes his lab's work will help guide scientists towards being able to program stem cells to repair damaged tissue, or even build new organs that grow with the right connections to the rest of the body.

"Wouldn't it be great," Lim said, "if we could grow a new organ directly in the body so that it specifically grows connected to the right places, where it's supposed to be?"

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stem cells; immune system; lymphoma; biotechnology and bioengineering; biotechnology; molecular biology; biochemistry; organic chemistry; batteries; computer programming; mobile computing; computers and internet

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Synthetic 'tissues' build themselves: Biologists program cells to self-organize into 3D-structures in a first step towards tissues that regrow and self-repair

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How do complex biological structures -- an eye, a hand, a brain -- emerge from a single fertilized egg? This is the fundamental question of developmental biology, and a mystery still being grappled with by scientists who hope to one day apply the same principles to heal damaged tissues or regrow ailing organs.

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New global data of invertebrate distributions suggests time holds key to species diversity.

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It's a puzzle that has confounded biologists for centuries: the earth's tropical regions are home to an enormous variety of plant and animal species, but as you travel north or south, away from the equator, the level of diversity dwindles.

Scientists don't know why biodiversity tends to concentrate around tropical regions, but they have put forward several hypotheses. One states that higher latitudes cannot support high biodiversity because of a lack of sunlight and heat. Another proposes that increased solar radiation in tropical latitudes could result in higher mutation rates there.

Yet a third points out that the colder ecosystems of earth are younger than their equatorial equivalents. During a period of rapid global cooling called the Eocene-Oligocene boundary, which occurred 34 million years ago, the planet's tropical habitats shrank dramatically toward the equator, while ice sheets grew at the poles. These newer, colder habitats have simply not existed long enough for as many species to accumulate as they have in the tropics, some scientists say.

Attempts to study this puzzle have involved comparing the number of species in several plant and animal groups, such as trees, birds and mammals, across distinct regions of the planet. But tallying species from Borneo to Belgium has yet to deliver concrete answers about why regional differences in diversity exist at all.

A team led by Prof. Evan Economo of the Okinawa Institute of Science and Technology Graduate University (OIST) set out to address this discrepancy with ants. While most studies up to now have focused on vertebrates like mammals and birds, ants offer a global, closely related group to examine. "They're found almost everywhere on the planet, they're ecologically dominant, and they are well-documented, at least for an insect group," said Prof. Economo. "This makes them a good example of invertebrates to compare with other vertebrate groups."

In a recent study published in Nature Communications, he and his colleagues painstakingly catalogued the global distribution of all 14,912 ant species. The process took years and involved poring through more than 9000 publications, museum databases and online repositories to define which ant species occur where in the world. Prof. Economo is leading this effort along with Dr. Benoit Guénard, a former postdoc in his lab who is now an assistant professor at the University of Hong Kong.

"Benoit was very determined to get these data together," said Prof. Economo. "He supervised a team of assistants digitizing data from papers during workdays, and spent his own nights, weekends, holidays entering data. It was an obsession, but the job couldn't have gotten done otherwise."

Complementing this mammoth task, the researchers also recreated a phylogeny of all the ant species that maps how current species and their ancestors are related to each other. To do so, they combined all the available genetic data and used computational models to infer a "tree of life" diagram that shows the ancestral relationships between species.

Additional data were gathered from 500 extinct species of ants that had been identified from fossils preserved in amber or compressed in rocks. This allowed the authors to date ancestors of modern tropical and temperate ant species and gain insight into past levels of diversity and the latitudes at which they occurred. (You can check out the data yourself on their website, antmaps.org)

These analyses revealed that the rate at which new species arise is highly variable, but is not higher near the equator. Rather, the paper suggests, tropical areas have had a much longer time to accumulate the diversity we see today, and given enough time, we could expect to see the same happen in other parts of the world.

"This new data from ants can help to test theories about large scale patterns in ecology," said Prof. Economo. Economo and Guénard also want to use it to guide conservation efforts by identifying important areas for insect biodiversity. Says Economo, "We are just now getting a first look at large-scale patterns of insect diversity."

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new species; nature; extinction; ecology research; biodiversity; rainforests; exotic species; ecology

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Ants provide clues to why biodiversity is higher in the tropics: New global data of invertebrate distributions suggests time holds key to species diversity

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It's a puzzle that has confounded biologists for centuries: the earth's tropical regions are home to an enormous variety of plant and animal species, but as you travel north or south, away from the equator, the level of diversity dwindles. Scientists don't know why biodiversity tends to concentrate around tropical regions, but they have put forward several hypotheses.

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What happens when pests resist all forms of herbicides and pesticides? To slow the evolutionary progression of weeds and insect pests gaining resistance to herbicides and pesticides, policymakers should provide resources for large-scale, landscape-level studies of a number of promising but untested approaches for slowing pest evolution.

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To slow the evolutionary progression of weeds and insect pests gaining resistance to herbicides and pesticides, policymakers should provide resources for large-scale, landscape-level studies of a number of promising but untested approaches for slowing pest evolution. Such landscape studies are now more feasible because of new genomic and technological innovations that could be used to compare the efficacy of strategies for preventing weed and insect resistance.

That's the takeaway recommendation from a North Carolina State University review paper addressing pesticide resistance published today in the journal Science.

Pesticide resistance exacts a tremendous toll on the U.S. agricultural sector, costing some $10 billion yearly. Costs could also increasingly accrue on human lives. If insecticide-coated bed nets and complementary insecticide spraying failed to slow the transmission of malaria by pesticide-resistant mosquitoes, for example, the human health costs in places like Africa could be catastrophic.

"What is the impact on people if these herbicides and pesticides run out?" said Fred Gould, William Neal Reynolds Professor of Agriculture at NC State and the corresponding author of the paper. "Resistance to pesticides is rising in critical weed and insect species, threatening our ability to harness these pests. Weed species have evolved resistance to every class of herbicide in use, and more than 550 arthropods have resistance to at least one pesticide."

Consider glyphosate, the powerhouse weed killer used ubiquitously in the United States to protect major crops like corn and soybeans. A bit more than 20 years ago, crops were genetically engineered to withstand glyphosate, allowing them to survive exposure to the chemical while weeds perished. By 2014, some 90 percent of planted U.S. corn, soybean and cotton crops were genetically modified to withstand glyphosate. Unfortunately, as the evolutionary arms race progresses, many weeds have figured out how to evolve resistance to glyphosate, making the chemical increasingly ineffective and forcing farmers to look for other or new solutions.

Some of these "new" solutions are actually old, as the herbicides 2,4-D and Dicamba, developed in the 1940s and 1960s, respectively, are currently getting a second look as possible widespread weed weapons.

"We're working down the list of available tools to fight weeds and insect pests," said Zachary Brown, assistant professor of agricultural and resource economics at NC State and a co-author of the paper. "It hasn't been economically feasible to develop new herbicides to replace glyphosate, for example, so what's old is becoming new again. But the current incentives don't seem to be right for getting us off this treadmill."

Besides ecology and economics, the authors stress that sociological and political perspectives also set up roadblocks to solving the problems of pest resistance. Cultural practices by farmers -- whether they till their land or not, how they use so-called refuges in combination with genetically modified crop areas and even how often they rotate their crops -- all play a big role in pest resistance.

"Any proposed solutions also need to include perspectives from the individual farmer, community and national levels," said Jennifer Kuzma, Goodnight-NC GSK Foundation Distinguished Professor and co-author of the paper.

The authors propose large-scale studies that would test the efficacy of a particular pesticide resistance strategy in one large area -- thousands of acres or more -- and how weeds and crop yields compare to large "control" areas that don't utilize that particular strategy. Farmers would receive incentives to participate; perhaps subsidies already allocated to farmers could be shifted to provide these participatory incentives, the authors suggest.

"In the end, are we going to outrun the pests or are they going to outrun us?" Gould said.

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agriculture and food; food and agriculture; genetically modified; biotechnology and bioengineering; exotic species; environmental policy; grassland; oceanography

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Pesticides: What happens if we run out of options?

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What happens when pests resist all forms of herbicides and pesticides? To slow the evolutionary progression of weeds and insect pests gaining resistance to herbicides and pesticides, policymakers should provide resources for large-scale, landscape-level studies of a number of promising but untested approaches for slowing pest evolution.

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A study offers an explanation for a mysterious and sometimes deadly weather pattern in which the jet stream, the global air currents that circle the Earth, stalls out over a region. Much like highways, the jet stream has a capacity, researchers said, and when it's exceeded, blockages form that are remarkably similar to traffic jams -- and climate forecasters can use the same math to model them both.

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from research organizations
Credit: NASA's Goddard Space Flight Center
The sky sometimes has its limits, according to new research from two University of Chicago atmospheric scientists.

A study published May 24 in Science offers an explanation for a mysterious and sometimes deadly weather pattern in which the jet stream, the global air currents that circle the Earth, stalls out over a region. Much like highways, the jet stream has a capacity, researchers said, and when it's exceeded, blockages form that are remarkably similar to traffic jams -- and climate forecasters can use the same math to model them both.

The deadly 2003 European heat wave, California's 2014 drought and the swing of Superstorm Sandy in 2012 that surprised forecasters -- all of these were caused by a weather phenomenon known as "blocking," in which the jet stream meanders, stopping weather systems from moving eastward. Scientists have known about it for decades, almost as long as they've known about the jet stream -- first discovered by pioneering University of Chicago meteorologist Carl-Gustaf Rossby, in fact -- but no one had a good explanation for why it happens.

"Blocking is notoriously difficult to forecast, in large part because there was no compelling theory about when it forms and why," said study coauthor Noboru Nakamura, a professor in the Department of the Geophysical Sciences.

Nakamura and then-graduate student Clare S.Y. Huang were studying the jet stream, trying to determine a clear set of measurements for blocking in order to better analyze the phenomenon. One of their new metrics was a term that measured the jet stream's meander. Looking over the math, Nakamura realized that the equation was nearly identical to one devised decades ago by transportation engineers trying to describe traffic jams.

"It turns out the jet stream has a capacity for 'weather traffic,' just as highway has traffic capacity, and when it is exceeded, blocking manifests as congestion," said Huang.

Much like car traffic, movement slows when multiple highways converge and the speed of the jet stream is reduced due to topography such as mountains or coasts.

The result is a simple theory that not only reproduces blocking, but predicts it, said Nakamura, who called making the cross-disciplinary connection "one of the most unexpected, but enlightening moments in my research career -- truly a gift from God."

The explanation may not immediately improve short-term weather forecasting, the researchers said, but it will certainly help predict long-term patterns, including which areas may see more drought or floods.

Their initial results suggest that while climate change probably increases blocking by running the jet stream closer to its capacity, there will be regional differences: for example, the Pacific Ocean may actually see a decrease in blocking over the decades.

"It's very difficult to forecast anything until you understand why it's happening, so this mechanistic model should be extremely helpful," Nakamura said.

And the model, unlike most modern climate science, is computationally simple: "This equation captures the essence with a much less complicated system," Huang said.
Story Source:
Materials provided by University of Chicago. Note: Content may be edited for style and length.

Journal Reference:

Noboru Nakamura, Clare S. Y. Huang. Atmospheric blocking as a traffic jam in the jet stream. Science, 2018; eaat0721 DOI: 10.1126/science.aat0721

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weather; climate; atmosphere; severe weather; computer modeling; mathematics; mathematical modeling; artificial intelligence

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New theory finds 'traffic jams' in jet stream cause abnormal weather patterns: Study explains blocking phenomenon that has baffled forecasters

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A study offers an explanation for a mysterious and sometimes deadly weather pattern in which the jet stream, the global air currents that circle the Earth, stalls out over a region. Much like highways, the jet stream has a capacity, researchers said, and when it's exceeded, blockages form that are remarkably similar to traffic jams -- and climate forecasters can use the same math to model them both.

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Scientists have developed a detailed analysis of how 22 recent hurricanes would be different if they formed under the conditions predicted for the late 21st century.

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Scientists have developed a detailed analysis of how 22 recent hurricanes would be different if they formed under the conditions predicted for the late 21st century.

While each storm's transformation would be unique, on balance, the hurricanes would become a little stronger, a little slower-moving, and a lot wetter.

In one example, Hurricane Ike -- which killed more than 100 people and devastated parts of the U.S. Gulf Coast in 2008 -- could have 13 percent stronger winds, move 17 percent slower, and be 34 percent wetter if it formed in a future, warmer climate.

Other storms could become slightly weaker (for example, Hurricane Ernesto) or move slightly faster (such as Hurricane Gustav). None would become drier. The rainfall rate of simulated future storms would increase by an average of 24 percent.

The study, led by scientists at the National Center for Atmospheric Research (NCAR) and published in the Journal of Climate, compares high-resolution computer simulations of more than 20 historical, named Atlantic storms with a second set of simulations that are identical but for a warmer, wetter climate that's consistent with the average scientific projections for the end of the century.
A future with Hurricane Harvey-like rains
"Our research suggests that future hurricanes could drop significantly more rain," said NCAR scientist Ethan Gutmann, who led the study. "Hurricane Harvey demonstrated last year just how dangerous that can be."

Harvey produced more than 4 feet of rain in some locations, breaking records and causing devastating flooding across the Houston area.

The research was funded by the National Science Foundation (NSF), which is NCAR's sponsor, and by DNV GL (Det Norske Veritas Germanischer Lloyd), a global quality assurance and risk management company.

"This study shows that the number of strong hurricanes, as a percent of total hurricanes each year, may increase," said Ed Bensman, a program director in NSF's Division of Atmospheric and Geospace Sciences, which supported the study. "With increasing development along coastlines, that has important implications for future storm damage."
Tapping a vast dataset to see storms
With more people and businesses relocating to coastal regions, the potential influence of environmental change on hurricanes has significant implications for public safety and the economy.

Last year's hurricane season, which caused an estimated $215 billion in losses according to reinsurance company Munich RE, was the costliest on record.

It's been challenging for scientists to study how hurricanes might change in the future as the climate continues to warm. Most climate models, which are usually run on a global scale over decades or centuries, are not run at a high enough resolution to "see" individual hurricanes.

Most weather models, on the other hand, are run at a high enough resolution to accurately represent hurricanes, but because of the high cost of computational resources, they are not generally used to simulate long-term changes in climate.

For the current study, the researchers took advantage of a massive new dataset created at NCAR. The scientists ran the Weather Research and Forecasting (WRF) model at a high resolution (4 kilometers, or about 2.5 miles) over the contiguous United States over two 13-year periods.

The simulations took about a year to run on the Yellowstone supercomputer at the NCAR-Wyoming Supercomputing Center in Cheyenne.

The first set of model runs simulates weather as it unfolded between 2000 and 2013, and the second simulates the same weather patterns but in a climate that's warmer by about 5 degrees Celsius (9 degrees Fahrenheit) -- the amount of warming that may be expected by the end of the century.

Drawing on the vast amount of data, the scientists created an algorithm that enabled them to identify 22 named storms that appear with very similar tracks in the historic and future simulations, allowing the hurricanes to be more easily compared.

As a group, storms in simulations of the future had 6 percent stronger average hourly maximum wind speeds than those in the past. They also moved at 9 percent slower speeds and had 24 percent higher average hourly maximum rainfall rates. Average storm radius did not change.
Each storm unique
"Some past studies have also run the WRF at a high resolution to study the impact of climate change on hurricanes, but those studies have tended to look at a single storm, like Sandy or Katrina," Gutmann said.

"What we find in looking at more than 20 storms is that some change one way, while others change in a different way. There is so much variability that you can't study one storm and then extrapolate to all storms."

But there was one consistent feature across storms: They all produced more rain.

While the study sheds light on how a particular storm might look in a warmer climate, it doesn't provide insight into how environmental change might affect storm genesis. That's because the hurricanes analyzed in this study formed outside the region simulated by the WRF model and passed into the WRF simulation as fully formed storms.

Other research has suggested that fewer storms may form in the future because of increasing atmospheric stability or greater high-level wind shear, though the storms that do form are apt to be stronger.

"It's possible that in a future climate, large-scale atmospheric changes wouldn't allow some of these storms to form," Gutmann said. "But from this study, we get an idea of what we can expect from the storms that do form."

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severe weather; storms; hurricanes and cyclones; weather; global warming; environmental issues; climate; environmental awareness

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Hurricanes: Stronger, slower, wetter in the future? New analysis compares 22 named storms with possible hurricanes of the future

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Scientists have developed a detailed analysis of how 22 recent hurricanes would be different if they formed under the conditions predicted for the late 21st century. While each storm's transformation would be unique, on balance, the hurricanes would become a little stronger, a little slower-moving, and a lot wetter.

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A new study that reconstructs the deep history of our planet's relationship to the moon shows that 1.4 billion years ago, a day on Earth lasted just over 18 hours. This is at least in part because the moon was closer and changed the way the Earth spun around its axis.

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For anyone who has ever wished there were more hours in the day, geoscientists have some good news: Days on Earth are getting longer.

A new study that reconstructs the deep history of our planet's relationship to the moon shows that 1.4 billion years ago, a day on Earth lasted just over 18 hours. This is at least in part because the moon was closer and changed the way Earth spun around its axis.

"As the moon moves away, the Earth is like a spinning figure skater who slows down as they stretch their arms out," explains Stephen Meyers, professor of geoscience at the University of Wisconsin-Madison and co-author of the study published this week [June 4, 2018] in the Proceedings of the National Academy of Sciences.

It describes a tool, a statistical method, that links astronomical theory with geological observation (called astrochronology) to look back on Earth's geologic past, reconstruct the history of the solar system and understand ancient climate change as captured in the rock record.

"One of our ambitions was to use astrochronology to tell time in the most distant past, to develop very ancient geological time scales," Meyers says. "We want to be able to study rocks that are billions of years old in a way that is comparable to how we study modern geologic processes."

Earth's movement in space is influenced by the other astronomical bodies that exert force on it, like other planets and the moon. This helps determine variations in Earth's rotation around and wobble on its axis, and in the orbit Earth traces around the sun.

These variations are collectively known as Milankovitch cycles and they determine where sunlight is distributed on Earth, which also means they determine Earth's climate rhythms. Scientists like Meyers have observed this climate rhythm in the rock record, spanning hundreds of millions of years.

But going back further, on the scale of billions of years, has proved challenging because typical geologic means, like radioisotope dating, do not provide the precision needed to identify the cycles. It's also complicated by lack of knowledge of the history of the moon, and by what is known as solar system chaos, a theory posed by Parisian astronomer Jacques Laskar in 1989.

The solar system has many moving parts, including the other planets orbiting the sun. Small, initial variations in these moving parts can propagate into big changes millions of years later; this is solar system chaos, and trying to account for it can be like trying to trace the butterfly effect in reverse.

Last year, Meyers and colleagues cracked the code on the chaotic solar system in a study of sediments from a 90 million-year-old rock formation that captured Earth's climate cycles. Still, the further back in the rock record he and others have tried to go, the less reliable their conclusions.

For instance, the moon is currently moving away from Earth at a rate of 3.82 centimeters per year. Using this present day rate, scientists extrapolating back through time calculated that "beyond about 1.5 billion years ago, the moon would have been close enough that its gravitational interactions with the Earth would have ripped the moon apart," Meyers explains. Yet, we know the moon is 4.5 billion years old.

So, Meyers sought a way to better account for just what our planetary neighbors were doing billions of years ago in order to understand the effect they had on Earth and its Milankovitch cycles. This was the problem he brought with him to a talk he gave at Columbia University's Lamont-Doherty Earth Observatory while on sabbatical in 2016.

In the audience that day was Alberto Malinverno, Lamont Research Professor at Columbia. "I was sitting there when I said to myself, 'I think I know how to do it! Let's get together!'" says Malinverno, the other study co-author. "It was exciting because, in a way, you dream of this all the time; I was a solution looking for a problem."

The two teamed up to combine a statistical method that Meyers developed in 2015 to deal with uncertainty across time -- called TimeOpt -- with astronomical theory, geologic data and a sophisticated statistical approach called Bayesian inversion that allows the researchers to get a better handle on the uncertainty of a study system.

They then tested the approach, which they call TimeOptMCMC, on two stratigraphic rock layers: the 1.4 billion-year-old Xiamaling Formation from Northern China and a 55 million-year-old record from Walvis Ridge, in the southern Atlantic Ocean.

With the approach, they could reliably assess from layers of rock in the geologic record variations in the direction of the axis of rotation of Earth and the shape of its orbit both in more recent time and in deep time, while also addressing uncertainty. They were also able to determine the length of day and the distance between Earth and the moon.

"In the future, we want to expand the work into different intervals of geologic time," says Malinverno.

The study complements two other recent studies that rely on the rock record and Milankovitch cycles to better understand Earth's history and behavior.

A research team at Lamont-Doherty used a rock formation in Arizona to confirm the remarkable regularity of Earth's orbital fluctuations from nearly circular to more elliptical on a 405,000 year cycle. And another team in New Zealand, in collaboration with Meyers, looked at how changes in Earth's orbit and rotation on its axis have affected cycles of evolution and extinction of marine organisms called graptoloids, going back 450 million years.

"The geologic record is an astronomical observatory for the early solar system," says Meyers. "We are looking at its pulsing rhythm, preserved in the rock and the history of life."

The study was funded by the National Science Foundation (EAR-1151438).

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comets and meteors; moon; astronomy; earth science; geology; geomagnetic storms; near-earth object impacts

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Thank the moon for Earth's lengthening day

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A new study that reconstructs the deep history of our planet's relationship to the moon shows that 1.4 billion years ago, a day on Earth lasted just over 18 hours. This is at least in part because the moon was closer and changed the way the Earth spun around its axis.

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Half of Antarctica has long thought to be seismically dormant, but a researcher tripled the number of recorded earthquakes by monitoring for just one year.

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Because instruments were finally installed there, scientists can no longer say that East Antarctica is unusually seismically silent.

Since the first earthquake was detected in 1982, there have been just eight more seismic events recorded in East Antarctica. But after a team that included Amanda Lough, PhD -- then a student but now an assistant professor in Drexel University's College of Arts and Sciences -- set up the first winter-through-summer seismic array, 27 earthquakes were recorded in 2009 alone, tripling the total number of events recorded on East Antarctica's section of the Earth's crust.

So instead of being exceptionally stable, it appears East Antarctica just wasn't being watched closely enough.

"Ultimately, the lack of recorded seismicity wasn't due to a lack of events but a lack of instruments close enough to record the events," explained Lough, who is the lead author on a study discussing the array's results in Nature Geoscience.

To scientists, East Antarctica is what's known as a "craton": a large, stable piece of rock on the Earth's crust that forms significant pieces of continents. But East Antarctica was always considered to be unusual for its lack of seismic activity. Many believed this was due to suppression via the incredible weight of Antarctica's thick ice.

Recordings from the array, however show that East Antarctica is similar to other cratons across the world, especially like the Canadian Shield, which stretches from the Northwest Territories to Quebec. The ice did not appear to be the culprit of the silence, it was solely a lack of ability to record what was happening.

Not having an array wasn't for lack of motivation, though. Setting up the array was no easy task, and it took a lot of determination and effort from the team Lough was on.

That included living in Antarctica's frigid, harsh environment, and flying from point to point across Antarctica's icy expanse (often having to dig out their own runways) to place the seismic recording equipment (which required even more digging). Those flights were usually cramped, with Lough wedging herself in among equipment and even fuel.

But the efforts paid off once the 27 earthquakes were all measured in 2009, each ranging in magnitude from 2.1 to 3.9.

Most seismic activity was recorded in basins near the Gumburtsev Subglacial Mountains, which Lough and others believe are part of an ancient continental rift system, older than the type in West Africa. "Rifts" are areas where the Earth's crust is being pulled apart from each other.

"There is a study we cite in the paper that shows that more than 52 percent of seismic events in continental areas occur in rifted crust, so it's not unexpected that we see the correlation here," Lough said.

Very little seismic activity was recorded outside of the rifts, which are similar to the New Madrid Seismic Zone in the southern Midwest United States.

"The rifts provide zones of weakness that enable faulting to occur more easily, and it may be that the situation here is such that activity is occurring preferentially along these areas of preexisting weakness," Lough said, though she emphasized "we only have one year of data" and more needs to be observed before they have a "full picture."

But the study from this array will contribute to gaining a fuller picture of what happens inside of the Earth's tectonic plates.

"East Antarctica is basically another piece of the puzzle," Lough said.

And while Antarctica is largely home to penguins, seals and not much else, what is learned there can provide lessons for the places on Earth where people do live. The big one: You don't know what you don't measure.

"Antarctica is the least-instrumented continent, but other areas of the globe also lack sufficient instrumentation," Lough said. "There are some obvious holes in coverage in the Global Seismic Network. For example, the ocean covers 71 percent of the planet, but it is expensive and very difficult to get instruments there. We need to think about improving coverage and then improving the density of it."

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earthquakes; natural disasters; snow and avalanches; earth science; geology; tsunamis; climate; global warming

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Long thought silent because of ice, study shows east Antarctica seismically active

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Because instruments were finally installed there, scientists can no longer say that East Antarctica is unusually seismically silent. Since the first earthquake was detected in 1982, there have been just eight more seismic events recorded in East Antarctica.

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Tens of thousands of sea turtles are caught each year by small-scale fishers off South America's Pacific coast, new research shows.

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Tens of thousands of sea turtles are caught each year by small-scale fishers off South America's Pacific coast, new research shows.

Surveys at 43 harbours in Ecuador, Peru and Chile reveal that gillnet fisheries catch more than 46,000 sea turtles per year, with more than 16,000 killed in the process.

And the true numbers are likely to be higher, as not all ports in each country were surveyed.

Such accidental catching -- known as bycatch -- is a major threat to species including sea turtles, and the researchers say their findings highlight Ecuador and Peru as key places to tackle this.

"People worry about industrial fisheries but a real concern that people are waking up to is small-scale fisheries," said Professor Brendan Godley, of the Centre for Ecology and Conservation on the University of Exeter's Penryn Campus in Cornwall.

"These are small vessels but they exist in such huge numbers that they can have a massive impact on ecosystems."

Turtles living in the study area include leatherbacks (critically endangered in the east Pacific) and hawksbills (critically endangered worldwide).

Dr Joanna Alfaro, who obtained her PhD at Exeter and is now director of ProDelphinus, a conservation organisation in Peru, said: "This work highlights the importance and the benefits of our approach of engaging with fishers.

"We are actively working with fishers in this region to develop and implement solutions to bycatch -- not just to improve the situation for turtles but for the health of fisheries and fish stocks.

"Our goal is to develop fisheries that are sustainable for small-scale fishing communities and the species with which they interact."

Dr Jeffrey Mangel, also of the University of Exeter and ProDelphinus, added: "Gathering this survey data was a massive effort across three countries, and the results give us fascinating and important insights.

"We are careful not to overstate threats to wildlife, but in this case it's clear that tens of thousands of turtles are being caught each year."

The southeastern Pacific sustains extensive fisheries that are important sources of food and employment for millions of people.

The study, supported by the UK government's Darwin Initiative, was designed to fill data gaps and identify priority areas for future conservation work.

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fish; endangered animals; fisheries; sea life; geography; ecology; sustainability; environmental awareness

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Thousands of turtles netted off South America

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Tens of thousands of sea turtles are caught each year by small-scale fishers off South America's Pacific coast, new research shows. Surveys at 43 harbours in Ecuador, Peru and Chile reveal that gillnet fisheries catch more than 46,000 sea turtles per year, with more than 16,000 killed in the process.

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When scientists found a resurgence of red spruce in northeastern forests, they had a lot of questions. Fifty years ago, red spruce was the equivalent of a canary in the coalmine signaling the effects of acid rain on forests. Researchers have identified two factors behind the tree's surprising recovery: reduced inputs of acid rain and warmer fall, winter and spring temperatures.

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from research organizations
Credit: Alexandra Kosiba, University of Vermont
Red spruce, for decades the forest equivalent of the canary in the coal mine signaling the detrimental effects of acid rain on northeastern forests, is making a comeback. New research by a team of scientists from the USDA Forest Service and the University of Vermont suggests that a combination of reduced pollution mandated by the 1990 Amendments to the Clean Air Act and changing climate are behind the resurgence.

The study, "The surprising recovery of red spruce growth shows links to decreased acid deposition and elevated temperature" by lead author Alexandra Kosiba of the University of Vermont with co-authors Paul Schaberg of the USDA Forest Service's Northern Research Station and University of Vermont researchers, was published this week in the journal Science of the Total Environment.

The research team assessed the relationship between red spruce growth and factors that may influence growth such as tree age and diameter, stand dynamics, plot characteristics (elevation, slope, aspect, geographical position), and environmental variables including temperature, precipitation, a suite of climate indices, and sulfur and nitrogen pollution deposition that cause acid deposition. In a study that encompassed 658 trees in 52 plots spanning five states, they found that more than 75 percent of red spruce trees and 90 percent of the plots examined in the study exhibited increasing growth since 2001.

"Our research suggests that the reductions we've seen in acid rain are making a difference to forests in the Northeast," said Schaberg. "Acid rain decline has helped red spruce recover, as well as higher temperatures in the fall, winter, and spring. Higher temperatures help some species and hurt others -- right now, red spruce are benefiting, but they could be vulnerable to change in the future."

Red spruce have unique characteristics that make them particularly susceptible to acid rain. For example, they have little genetic variation and they have only moderate tolerance to the cold. But they are also able to "wake up" and photosynthesize during warm interludes of the dormant season, a characteristic that may better position the species to take advantage of recent climate shifts that extend the functional growing season. Yet the study notes that future changes in habitat suitability may not be as favorable to red spruce as those already experienced -- it will likely depend on how extreme future changes are.

Scientists are confident that their research represents the state of red spruce in the entire region, according to Kosiba. "Our study included a broad range of tree ages and sizes as well as a variety of plot locations and characteristics," she said. "We are confident that we are capturing the regional status of red spruce forests, not just a snapshot of a specific location."

"More broadly our work demonstrates the importance of using research to identify ecosystem problems that inform policy to mitigate those issues, and result in biological recovery," noted Kosiba.

Journal Reference:

Alexandra M. Kosiba, Paul G. Schaberg, Shelly A. Rayback, Gary J. Hawley. The surprising recovery of red spruce growth shows links to decreased acid deposition and elevated temperature. Science of The Total Environment, 2018; 637-638: 1480 DOI: 10.1016/j.scitotenv.2018.05.010

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trees; beer and wine; ecology research; soil types; forest; acid rain; environmental issues; rainforests

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Surprising resurgence of red spruce likely result of cleaner air and warmer winters

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When scientists found a resurgence of red spruce in northeastern forests, they had a lot of questions. Fifty years ago, red spruce was the equivalent of a canary in the coalmine signaling the effects of acid rain on forests. Researchers have identified two factors behind the tree's surprising recovery: reduced inputs of acid rain and warmer fall, winter and spring temperatures.

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Photographs that are automatically collected by motion-sensor cameras can be automatically described by deep neural networks. The result is a system that can automate animal identification for up to 99.3 percent of images while still performing at the same 96.6 percent accuracy rate of crowdsourced teams of human volunteers.

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A new paper in the Proceedings of the National Academy of Sciences (PNAS) reports how a cutting-edge artificial intelligence technique called deep learning can automatically identify, count and describe animals in their natural habitats.

Photographs that are automatically collected by motion-sensor cameras can then be automatically described by deep neural networks. The result is a system that can automate animal identification for up to 99.3 percent of images while still performing at the same 96.6 percent accuracy rate of crowdsourced teams of human volunteers.

"This technology lets us accurately, unobtrusively and inexpensively collect wildlife data, which could help catalyze the transformation of many fields of ecology, wildlife biology, zoology, conservation biology and animal behavior into 'big data' sciences. This will dramatically improve our ability to both study and conserve wildlife and precious ecosystems," says Jeff Clune, the senior author of the paper. He is the Harris Associate Professor at the University of Wyoming and a senior research manager at Uber's Artificial Intelligence Labs.

The paper was written by Clune; his Ph.D. student Mohammad Sadegh Norouzzadeh; his former Ph.D. student Anh Nguyen (now at Auburn University); Margaret Kosmala (Harvard University); Ali Swanson (University of Oxford); and Meredith Palmer and Craig Packer (both from the University of Minnesota).

Deep neural networks are a form of computational intelligence loosely inspired by how animal brains see and understand the world. They require vast amounts of training data to work well, and the data must be accurately labeled (e.g., each image being correctly tagged with which species of animal is present, how many there are, etc.).

This study obtained the necessary data from Snapshot Serengeti, a citizen science project on the http://www.zooniverse.org platform. Snapshot Serengeti has deployed a large number of "camera traps" (motion-sensor cameras) in Tanzania that collect millions of images of animals in their natural habitat, such as lions, leopards, cheetahs and elephants. The information in these photographs is only useful once it has been converted into text and numbers. For years, the best method for extracting such information was to ask crowdsourced teams of human volunteers to label each image manually. The study published today harnessed 3.2 million labeled images produced in this manner by more than 50,000 human volunteers over several years.

"When I told Jeff Clune we had 3.2 million labeled images, he stopped in his tracks," says Packer, who heads the Snapshot Serengeti project. "We wanted to test whether we could use machine learning to automate the work of human volunteers. Our citizen scientists have done phenomenal work, but we needed to speed up the process to handle ever greater amounts of data. The deep learning algorithm is amazing and far surpassed my expectations. This is a game changer for wildlife ecology."

Swanson, who founded Snapshot Serengeti, adds: "There are hundreds of camera-trap projects in the world, and very few of them are able to recruit large armies of human volunteers to extract their data. That means that much of the knowledge in these important data sets remains untapped. Although projects are increasingly turning to citizen science for image classification, we're starting to see it take longer and longer to label each batch of images as the demand for volunteers grows. We believe deep learning will be key in alleviating the bottleneck for camera-trap projects: the effort of converting images into usable data."

"Not only does the artificial intelligence system tell you which of 48 different species of animal is present, but it also tells you how many there are and what they are doing. It will tell you if they are eating, sleeping, if babies are present, etc.," adds Kosmala, another Snapshot Serengeti leader. "We estimate that the deep learning technology pipeline we describe would save more than eight years of human labeling effort for each additional 3 million images. That is a lot of valuable volunteer time that can be redeployed to help other projects."

First-author Sadegh Norouzzadeh points out that "Deep learning is still improving rapidly, and we expect that its performance will only get better in the coming years. Here, we wanted to demonstrate the value of the technology to the wildlife ecology community, but we expect that as more people research how to improve deep learning for this application and publish their datasets, the sky's the limit. It is exciting to think of all the different ways this technology can help with our important scientific and conservation missions."

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animal learning and intelligence; nature; wild animals; behavioral science; information technology; photography; hacking; computers and internet

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Use artificial intelligence to identify, count, describe wild animals

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Photographs that are automatically collected by motion-sensor cameras can be automatically described by deep neural networks. The result is a system that can automate animal identification for up to 99.3 percent of images while still performing at the same 96.6 percent accuracy rate of crowdsourced teams of human volunteers.

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A mix of fly species preserved from these times in a rare lake sediment core shows that Greenland was even warmer than previously thought. This information could help researchers better gauge Greenland's sensitivity to warming, by testing and improving models of climate and ice sheet behavior.

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A tiny clue found in ancient sediment has unlocked big secrets about Greenland's past and future climate.

Just beyond the northwest edge of the vast Greenland Ice Sheet, Northwestern University researchers have discovered lake mud that beat tough odds by surviving the last ice age. The mud, and remains of common flies nestled within it, record two interglacial periods in northwest Greenland. Although researchers have long known these two periods -- the early Holocene and Last Interglacial -- experienced warming in the Arctic due to changes in Earth's orbit, the mix of fly species preserved from these times shows that Greenland was even warmer than previously thought.

This information could help researchers better gauge Greenland's sensitivity to warming, by testing and improving models of climate and ice sheet behavior. Those models could then improve predictions of how Greenland's ice sheet, which covers 80 percent of the Arctic country and holds enough ice to equal 20 feet of global sea level, might respond to human-made global warming.

"Northwest Greenland might feel really remote, but what happens to that ice sheet is going to matter to everyone in New York City, Miami and every coastal city around the world," said Yarrow Axford, the study's senior author and an associate professor of Earth and planetary sciences at Northwestern. "One of the big uncertainties in climate science remains how fast the Earth changes when it gets warmer. Geology gives us an opportunity to see what happened when the Earth was warmer than today."

Published June 4 in the Proceedings of the National Academy of Sciences, the study included contributions from collaborators at Dartmouth College.

People might be surprised to see how today's frigid Greenland looked during the last two interglacial periods. Today, northwest Greenland hovers in the 30s and low 40s Fahrenheit and weathers snowstorms in summer. But average summer temperatures in the early Holocene (8,000 to 11,000 years ago) and Last Interglacial (116,000 to 130,000 years ago) climbed well into the 50s.

During the Last Interglacial, global sea levels increased by 15 to 30 feet, largely due to thinning of Greenland and Antarctica's ice sheets. But now Northwestern's team believes northern Greenland's ice sheet experienced stronger warming than previously thought, which could mean that Greenland is more responsible for that sea-level rise.
Layers of time
To measure these ancient temperatures, researchers look to ice cores and lake sediment cores. Because ice and lake sediment form by an incremental buildup on annual layers of snow or mud, these cores contain archives of the past. By looking through the layers, researchers can pinpoint climate clues from eons ago. Finding lake sediments older than about 10,000 years, however, has been historically very difficult in Greenland.

"The classic thing that glaciers do is slide," Axford said. "So when the ice sheet grows larger, all this wonderful geology gets scooped up and spat out into the oceans."

But Axford's team found an area where this wasn't the case.

The climate in northwest Greenland houses the perfect conditions to preserve the sediments within a small lake that Axford's team affectionately calls "Wax Lips Lake" because of its shape.

"During the last ice age, the ice sheet there was just thin enough, and the atmosphere was just cold enough that the ice sheet froze to the ground instead of melting at its base and sliding," said Jamie McFarlin, a Ph.D. student in Northwestern's department of Earth and planetary sciences, who led the study. "It grew on top of itself and preserved most of the geology below."

"The ice gently tip-toed over this spot instead of plowing over it," Axford added.

After taking a two-meter-long tube of sediment from Wax Lips Lake's lakebed, McFarlin combed through the layers to investigate those from the early Holocene and Last Interglacial periods. It was then that she noticed a mix of lake fly species, called chironomids, that suggested a warmer climate during both periods. Especially surprising: The Last Interglacial period swarmed with another type of insect known as the phantom midge. Although phantom midges have been reported in low abundance in northern climates, one would have to travel 1,000 miles south to Canada's Labrador province to find phantom midges at comparable abundance to the Last Interglacial in northwest Greenland.

"As far as we know, it's never been found in Greenland. We think this is the first time anyone has reported it in ancient sediments or modern lakes there," Axford said. "We were really surprised to see how far north it migrated."
The bigger picture
Discovering this mix of insects means northwest Greenland's average July during the last two interglacial periods most likely climbed above 50 degrees and possibly into the high 50s during the Last Interglacial. This confirms controversial geological records constructed from ice cores taken nearby, which also indicated significant warming during these time periods.

"Other records have shown that northern Greenland's climate was much warmer than people expected during those periods, and those results received justified skepticism," Axford said. "Now we have an independent record that confirms that when the Arctic warmed in the past, there was especially strong warming in northern Greenland."

This data will help the broader scientific community further hone climate and ice sheet models used to project future changes.

"This is the kind of ground-truthing that we need to get really accurate climate models and projections," said Magdalena Osburn, an assistant professor of Earth and planetary sciences at Northwestern, who coauthored the study. "We're finding that, in some cases, models don't include temperatures that are warm enough for this part of the world."

There is one caveat. Well-known changes in Earth's orbit caused warming during the early Holocene and Last Interglacial periods. Today, warming stems from human-made sources and is happening much faster than warming during those interglacial periods. That means there is a chance that Earth might not respond to current-day warming in the same way.

"Past climate is our best analog for future warming, and our results hint that land at these very high latitudes in the Arctic may warm even more than predicted in the coming century," Axford said. "But nothing in Earth's past is a perfect analog because what's happening today is totally unprecedented."

This work was supported by the National Science Foundation (NSF) Office of Polar Programs (awards 1108306 and 1107411), an NSF Graduate Research Fellowship, the Geological Society of America and the Institute for Sustainability and Energy at Northwestern.

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global warming; climate; ice ages; environmental issues; early climate; ancient dna; evolution; fossils

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Ancient Greenland was much warmer than previously thought: New knowledge helps researchers understand how Greenland's ice sheet responds to warming

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Although researchers have long known that the last two interglacial periods experienced warming in the Arctic due to changes in the Earth's orbit, a mix of fly species preserved from these times in a rare lake sediment core shows that Greenland was even warmer than previously thought.

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Brine shrimp moving vertically in two different laboratory tanks created small eddies that aggregated into a jet roughly the size of the whole migrating group, researchers report online April 18 in Nature. With a fluid velocity of about 1 to 2 centimeters per second, the jet was also powerful enough to mix shallow waters with deeper, saltier waters. Without mixing, these waters of different densities would remain isolated in layers.

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When it comes to tiny ocean swimmers, the whole is much greater than the sum of its parts. Ocean turbulence stirred up by multitudes of creatures such as krill can be powerful enough to extend hundreds of meters down into the deep, a new study suggests.

Brine shrimp moving vertically in two different laboratory tanks created small eddies that aggregated into a jet roughly the size of the whole migrating group, researchers report online April 18 in Nature. With a fluid velocity of about 1 to 2 centimeters per second, the jet was also powerful enough to mix shallow waters with deeper, saltier waters. Without mixing, these waters of different densities would remain isolated in layers.

The shrimp represent centimeter-sized swimmers, including krill and shrimplike copepods, found throughout the world's oceans that may together be capable of mixing ocean layers - and delivering nutrient-rich deep waters to phytoplankton, or microscopic marine plants, near the surface, the researchers suggest.
"The original thinking is that these animals would flap their appendages and create little eddies about the same size as their bodies," says John Dabiri, an expert in fluid dynamics at Stanford University. Previous work, including acoustic measurements of krill migrations in the ocean (SN: 10/7/06, p. 238) and theoretical simulations of fluid flow around swimmers such as jellyfish and shrimplike copepods (SN: 8/29/09, p. 14), had suggested that they may be stirring up more turbulence than thought.
In 2014, Dabiri coauthored a study that debuted the laboratory tank setup also used in the new research. That paper noted that migrating brine shrimp created jets and eddies much larger than themselves. "But there was skepticism about whether those lab results were relevant to the ocean," Dabiri says. The 2014 study didn't account for how ocean water stratifies into layers that don't easily mix, due to differences in salinity or temperature. It wasn't clear if shrimp-generated turbulence could be strong enough and extend deep enough to overcome the physical barriers and mix the layers.

The new research used a 1.2-meter-deep tank and a 2-meter-deep tank. Each held tens of thousands of wiggly brine shrimp in two layers of water of different densities. The researchers used LED lights to prompt the shrimp to migrate upward or downward, mimicking the massive daily, vertical migrations of krill, copepods and other ocean denizens. The shrimp migrated in close proximity to one another - and that helped to magnify their individual efforts, the scientists found.

"As one animal swims upward, it's kicking backward," Dabiri says. That parcel of water then gets kicked downward by another nearby animal, and then another. The result is a downward rush that gets stronger as the migration continues, and eventually extends about as deep as the entire migrating group. In the ocean, that could be as much as hundreds of meters.

JET STREAM Tens of thousands of brine shrimp swimming upward in a laboratory tank produce a large jet of water the size of the whole group, mixing shallow water with deeper, saltier water. In the ocean, daily, vertical migrations of similarly small swimmers such as krill may cause large-scale mixing, bringing up key nutrients from the deep.

Isabel Houghton, J.R. Strickler/University of Wisconsin-Milwaukee

"At the heart of the investigation is the question about whether life in the ocean, as it moves about the environment, does any important 'mixing,' " says William Dewar, an oceanographer at Florida State University in Tallahassee. "These results argue quite compellingly that they do, and strongly counter the concern that most marine life is simply too small in size to matter."

The team's finding opens the door to a host of interesting questions, Dewar adds. Ocean mixing is an important part of the global climate cycle: It churns up nutrients that feed phytoplankton blooms and aids the exchange of gases with the atmosphere. Adding biologically driven mixing to physical processes in the ocean makes the equation even more complex, he says.

The next step will be to try to observe the effect at sea, using shipboard measurements, Dabiri says. "Previous studies looked for turbulence or eddies on the scale of the animals' size," he says, instead of large downward jets. "This paper tells us for the first time what to look for."

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Masses of shrimp and krill may play a huge role in mixing oceans

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When it comes to tiny ocean swimmers, the whole is much greater than the sum of its parts. Ocean turbulence stirred up by multitudes of creatures such as krill can be powerful enough to extend hundreds of meters down into the deep, a new study suggests.

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Designing plastics that can be easily reused is one line of attack against the global plastic waste problem. Only about 10 percent of plastic ever made gets recycled, according to a 2017 study in Science Advances. But the material is so cheap and useful that hundreds of millions of tons of it keeps getting churned out each year.

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There's a great future in plastics.

A new kind of plastic can, when exposed to the right chemicals, break down into the same basic building blocks that it came from and be rebuilt again and again. The recyclable material is more durable than previous attempts to create reusable plastics, researchers report inthe April 27 Science.

Designing plastics that can be easily reused is one line of attack against the global plastic waste problem. Only about 10 percent of plastic ever made gets recycled, according to a 2017 study in Science Advances. But the material is so cheap and useful that hundreds of millions of tons of it keeps getting churned out each year.

A major impediment to plastic recycling is that most plastics degrade into molecules that aren't immediately useful. Transforming those molecules back into plastic or into some other product requires many chemical reactions, which makes the recycling process less efficient. And while biodegradable plastics have become popular in recent years, they break down only if the right microbes are present. More often than not, these plastics end up lingering in landfills or floating in the ocean. Creating plastics that could be broken down into their building blocks and reused without additional processing and purifying could help reduce the pollution buildup.

But designing such a plastic polymer is a balancing act, says Michael Shaver, a polymer chemist at the University of Edinburgh who wasn't part of the study. Polymers are long chains of small molecules, called monomers, that link together like beads on a string. Monomers that need extreme temperatures or too much chemical coaxing to join up into polymers might not be practical building blocks. And resulting polymers need to be stable up to a high enough temperature that, say, pouring hot coffee into a cup made of them won't destabilize the chains and make the plastic melt into a sticky puddle.
Polymer chemist Jianbo Zhu and his colleagues at Colorado State University in Fort Collins set out to solve this challenge. The team had had some luck in the past creating a polymer that could be broken down into its starting molecules. But the resulting plastics created by their lab and others on the same track were too soft and temperature-sensitive to have much practical use.
This time, Zhu and his colleagues modified one of their previous creations, a small ringed molecule, by adding another ring in a way that braced the molecule into a particular conformation. That rigidity helped the monomers quickly link together at room temperature into polymer chains that are heat-stable.

Then, when exposed to certain mild chemicals or high enough heat, the polymers degraded back into monomers. The researchers were able to repeat this cycle several times, showing that, in theory, the polymer could be infinitely recyclable.

While each monomer is locked into a particular conformation, not all of them have the same shape even though they're made from the same chemical recipe. Mixing two different conformations of monomers created an even stronger plastic, says Zhu.

"This is probably the best system out there," Shaver says.

Still, it's not perfect yet: Zhu and his colleagues plan to tinker with the monomer design more in the future to make the resulting plastic a bit less brittle. Eventually, they hope to commercialize the product.

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This plastic can be recycled over and over and over again

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There's a great future in plastics. A new kind of plastic can, when exposed to the right chemicals, break down into the same basic building blocks that it came from and be rebuilt again and again. The recyclable material is more durable than previous attempts to create reusable plastics, researchers report inthe April 27 Science.

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These bees make enzymes that help the insects break down a type of neonicotinoid called thiacloprid, scientists report March 22 in Current Biology. Neonicotinoids have been linked to negative effects on bee health, such as difficulty reproducing in honeybees

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Honeybees and bumblebees have a way to resist toxic compounds in some widely used insecticides.

These bees make enzymes that help the insects break down a type of neonicotinoid called thiacloprid, scientists report March 22 in Current Biology. Neonicotinoids have been linked to negative effects on bee health, such as difficulty reproducing in honeybees ( SN: 7/26/16, p 16). But bees respond to different types of the insecticides in various ways. This finding could help scientists design versions of neonicotinoids that are less harmful to bees, the researchers say.

Such work could have broad ramifications, says study coauthor Chris Bass, an applied entomologist at the University of Exeter in England. "Bees are hugely important to the pollination of crops and wild flowers and biodiversity in general."

Neonicotinoids are typically coated on seeds such as corn and sometimes sprayed on crops to protect the plants from insect pests. The chemicals are effective, but their use has been suspected to be involved in worrisome declines in numbers of wild pollinators ( SN Online: 4/5/12).

Maj Rundlöf of Lund University in Sweden helped raise the alarm about the insecticides. In 2015, she reported that neonicotinoid-treated crops reduced the populations of bees that fed from the plants. Rundlöf, who was not involved with the new study, says the new research is important because it clarifies differences between the insecticides. "All neonicotinoids are not the same," she says. "It's a bit unrealistic to damn a whole group of pesticides."

Bass and his colleagues, which include scientists from Bayer, one of the main producers of neonicotinoids, investigated resistance to thiacloprid by looking at bees' defense systems. The team focused on enzymes known as P450s, which can metabolize toxic chemicals, breaking them down before they affect the bee nervous system. The researchers used drugs to inhibit groups of P450 enzymes. When the family enzymes called CYP9Q was inhibited, bees became 170 times as sensitive to thiacloprid, dying from a much smaller dose, the researchers found. Discovering the enzymes' protective power could lead to more effective ways to simultaneously avoid harming bees and help crops.

"We live in an era that uses pesticides," Rundlöf says. "We need to figure out the ones that are safest."

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How bees defend against some controversial insecticides

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Honeybees and bumblebees have a way to resist toxic compounds in some widely used insecticides. These bees make enzymes that help the insects break down a type of neonicotinoid called thiacloprid, scientists report March 22 in Current Biology. Neonicotinoids have been linked to negative effects on bee health, such as difficulty reproducing in honeybees ( SN: 7/26/16, p 16).

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The bay’s aquatic vegetation, including seagrasses and freshwater grasses, is an important part of coastal ecosystems, says study coauthor Jonathan Lefcheck, a marine ecologist at the Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine. Beds of underwater grasses act as nurseries that shelter young fish and aquatic invertebrates

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Underwater grasses are growing back in the Chesapeake Bay. The plants now carpet three times as much real estate as in 1984, thanks to more than 30 years of efforts to reduce nitrogen pollution. This environmental success story shows that regulations put in place to protect the bay's health have made a difference, researchers report the week of March 5 in Proceedings of the National Academy of Sciences.

Rules limiting nutrient runoff from farms and wastewater treatment plants helped to decrease nitrogen concentrations in the bay by 23 percent since 1984. That decline in nitrogen has allowed the recovery of 17,000 hectares of grasses, the new study shows - enough to cover roughly 32,000 football fields.

"This is one of the best examples we have of linking long-term research data with management to show how important that is in restoring this critical habitat," says Karen McGlathery, an environmental scientist at the University of Virginia in Charlottesville who wasn't involved in the research. "I don't know of any other system that's so large and so complicated where these connections have been made."

The bay's aquatic vegetation, including seagrasses and freshwater grasses, is an important part of coastal ecosystems, says study coauthor Jonathan Lefcheck, a marine ecologist at the Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine. Beds of underwater grasses act as nurseries that shelter young fish and aquatic invertebrates. The plants clean the water by trapping particulates, and stabilize shorelines by preventing erosion. But the once-lush grasses began dying off in the 1950s when the region's human population boomed, and cities and farms dumped increasing amounts of nitrogen and other nutrients into the bay.

In the late 1970s and early 1980s, state and federal agencies took action, limiting the amount of nutrients that could enter the bay from farms, water treatment facilities and other sources. Those groups also instituted programs to monitor the bay's health, building up the stockpile of information that Lefcheck and his colleagues have now analyzed.

The researchers looked at aerial surveys of the bay, data on water temperature and nutrient levels, as well as land and fertilizer use. Using mathematical equations to test which variables had the biggest impact on seagrass regrowth, the team pinned down nitrogen reduction as the driving force. That makes sense: Too much nitrogen in water promotes the growth of plankton, which can block sunlight, and algae, which can settle on the grass blades and smother them.

Now, though, researchers are seeing just the opposite. Grasses need clean water to get a foothold, but once they settle in, they "modify their own environment and make it better," Lefcheck says. "Once you get a little bit established, it can take off."

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Pollution regulations help Chesapeake Bay seagrass rebound

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Underwater grasses are growing back in the Chesapeake Bay. The plants now carpet three times as much real estate as in 1984, thanks to more than 30 years of efforts to reduce nitrogen pollution.

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The plants now carpet three times as much real estate as in 1984, thanks to more than 30 years of efforts to reduce nitrogen pollution.

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Underwater grasses are growing back in the Chesapeake Bay. The plants now carpet three times as much real estate as in 1984, thanks to more than 30 years of efforts to reduce nitrogen pollution. This environmental success story shows that regulations put in place to protect the bay's health have made a difference, researchers report the week of March 5 in Proceedings of the National Academy of Sciences.

Rules limiting nutrient runoff from farms and wastewater treatment plants helped to decrease nitrogen concentrations in the bay by 23 percent since 1984. That decline in nitrogen has allowed the recovery of 17,000 hectares of grasses, the new study shows - enough to cover roughly 32,000 football fields.

"This is one of the best examples we have of linking long-term research data with management to show how important that is in restoring this critical habitat," says Karen McGlathery, an environmental scientist at the University of Virginia in Charlottesville who wasn't involved in the research. "I don't know of any other system that's so large and so complicated where these connections have been made."

The bay's aquatic vegetation, including seagrasses and freshwater grasses, is an important part of coastal ecosystems, says study coauthor Jonathan Lefcheck, a marine ecologist at the Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine. Beds of underwater grasses act as nurseries that shelter young fish and aquatic invertebrates. The plants clean the water by trapping particulates, and stabilize shorelines by preventing erosion. But the once-lush grasses began dying off in the 1950s when the region's human population boomed, and cities and farms dumped increasing amounts of nitrogen and other nutrients into the bay.

In the late 1970s and early 1980s, state and federal agencies took action, limiting the amount of nutrients that could enter the bay from farms, water treatment facilities and other sources. Those groups also instituted programs to monitor the bay's health, building up the stockpile of information that Lefcheck and his colleagues have now analyzed.

The researchers looked at aerial surveys of the bay, data on water temperature and nutrient levels, as well as land and fertilizer use. Using mathematical equations to test which variables had the biggest impact on seagrass regrowth, the team pinned down nitrogen reduction as the driving force. That makes sense: Too much nitrogen in water promotes the growth of plankton, which can block sunlight, and algae, which can settle on the grass blades and smother them.

Now, though, researchers are seeing just the opposite. Grasses need clean water to get a foothold, but once they settle in, they "modify their own environment and make it better," Lefcheck says. "Once you get a little bit established, it can take off."

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Pollution regulations help Chesapeake Bay seagrass rebound

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Underwater grasses are growing back in the Chesapeake Bay. The plants now carpet three times as much real estate as in 1984, thanks to more than 30 years of efforts to reduce nitrogen pollution.

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Smith estimates that the fires and smoke killed 100,000 people in Indonesia and neighboring countries and caused billions of dollars in damage.

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In 2015, massive wildfires burned through Indonesia, sending thick smoke and haze as far as Thailand.

These fires were "the worst environmental disaster in modern history," says Thomas Smith, a wildfire expert at King's College London. Smith estimates that the fires and smoke killed 100,000 people in Indonesia and neighboring countries and caused billions of dollars in damage. The fires were costly for the rest of the planet, too: At their peak, the blazes belched more climate-warming carbon dioxide into the atmosphere each day than did all U.S. economic activity.

Two years later and 13,000 kilometers away, a fire smoldered on the fringes of a barren, northern landscape. The remote blaze could have gone unnoticed. But Jessica McCarty and other fire researchers actively monitor satellite imagery of Earth the way some people check Facebook. One Sunday in August, McCarty, of Miami University in Ohio, was surprised to see massive plumes of what appeared to be white smoke over a swath of Greenland. The giant landmass had not been on her fire radar. It's mostly ice, and the parts that aren't have sparse vegetation.

The settings of these two blazes couldn't have been more different, but scientists suspect the two had something important in common: plenty of decaying organic matter known as peat.

Peatlands - which include bogs, other swampy wetlands and, yes, Greenland's icy soil - are ecosystems rich in decayed organic matter.

In their healthy, soggy state, peatlands are quite fire resistant. So when it comes to fire risk, peat-heavy landscapes haven't historically gotten the same attention as, say, the dry pine forests of the western United States. But with those devastating peat fires in Indonesia, the spotlight has turned to the planet's other peatlands, too.

Worldwide, peatlands store massive amounts of carbon in thick blankets of wet organic matter accumulated in the ground over centuries. And though they cover just 3 to 5 percent of Earth's land surface, peatlands store a quarter of all soil carbon. That adds up to more carbon than all of the world's forests combined.

But changes in land use - draining the water to plant acres of crops that demand drier soil, a common practice in tropical regions, or building a road through an area - can dry out the peat. And then, a single carelessly tossed cigarette or an errant lightning strike can ignite a fire that will smoke and smolder for months, releasing thousands of years of stored carbon as carbon dioxide into the atmosphere.

Or fires set to clear land for agriculture can get out of hand, like they've done in Indonesia: Over the last few decades, the country has drained many of its peatlands to grow oil palms and other crops. Now, the country is seeing the worst-case scenario of what can happen when peatlands are disrupted and desiccated. In northern latitudes, meanwhile, thawing permafrost exposes peat that has been buried for years, which can fuel fires like those seen in Greenland last summer.

In the short term, peat fires clog the air with deadly smoke and smog. In densely populated areas such as Indonesia, blazes can devour homes and businesses and claim lives. But the fires' impact lingers long after the flames die down. Peat fires reshape entire ecosystems. Once the peat burns away, it can take thousands of years to build up again. And all of the carbon that was once neatly stored away is instead floating around in the atmosphere, contributing to climate change much like burning coal does.

Now, scientists are trying to get a better handle on peatlands and the effects of agriculture, development and a climate that's shifting toward warmer and drier. Recent discoveries of hidden peatlands in Africa and South America expand the extent of peat around the world, and up the stakes for protecting those carbon stores. New research is making it increasingly clear that, without a shift in approach, humans might strip away healthy peatlands and get, in return, a lot of climate-warming carbon dioxide.

Meet peat

Bogs don't conjure warm, fuzzy feelings for most people. The landscapes are often associated in popular culture with witches, Europe's mummified "bog bodies" and dreary weather. It's perhaps telling that "quagmire" - another word for a bog - is also used to refer to a sticky predicament. But to the scientists who study them, bogs are far from bleak.

"Most people walk far, far out of their way to avoid walking through these things, but I love them," says Merritt Turetsky, a peat researcher at the University of Guelph in Canada. The bogs that she studies in Canada and Alaska look like "hobbit ecosystems," she says, with all of the action happening low to the ground: stunted trees studding a colorful carpet of mosses and lichens. And, she points out, bogs play a crucial role in keeping our planet healthy.

Carbon is constantly being recycled throughout the world: It's taken in by plants as carbon dioxide, for example, and is dissolved in the oceans. But excess circulating carbon can throw ecosystems out of whack. Too much carbon dioxide in the atmosphere makes the planet heat up; too much dissolved in the ocean makes the water more acidic. Long-term carbon stores in ocean sediments and rocks such as limestone pull carbon out of the short-term cycle, cloistering it where it can't do harm. The same goes for peatlands; dig down many meters into a bog, and you'll find carbon that's been buried for thousands of years.

And while the untrained eye might look at a bog and see nothing but a soggy morass that calls for waterproof waders, peatlands can be surprisingly diverse. In the tropics, where swamp forests are filled with large, leafy trees, blankets of peat are typically built up by decayed woody plants. Temperate peatlands, like those in the northern United States and Canada, sport scrubbier vegetation and are made mostly from decayed sphagnum moss.

Peat is "not exactly nonrenewable, but it accumulates so slowly," Turetsky says. "A fire can burn through a dry bog and literally release thousands of years of carbon in a couple minutes of combustion." She learned that firsthand as a graduate student.

Almost 20 years ago, she buried small bags of peat in a Canadian bog to study their decomposition. When she returned two years later to dig up the samples, her entire field site had gone up in smoke. Her precious data were gone.

"I was devastated for about a day," Turetsky says. "But then I started thinking about it: We were shocked that this system had burned."

The very next day, she started collecting new data, this time observing how the bog recovered from the fire. Back then, she says, people assumed that the only thing slowing down the accumulation of peat was its inevitable natural decomposition over time. "It was the first time I realized that decomposition wasn't the only process leading to peat loss," Turetsky says. "Fire also reduces peat by combusting it."

Hidden deposits

With an increased awareness of the threats to bogs has come a greater push to identify and protect the resources contained in these ecosystems. Recently, large new peat-rich spots have been discovered around the world. In January 2017, British and Congolese scientists announced in Nature that huge tracts of peat have been hiding in a lush expanse of forest straddling the equator in the Central Congo Basin. The area is home to groups of indigenous people but difficult for outsiders to access, so nobody had surveyed its peat resources until recently.

The researchers, led by Simon Lewis and Greta Dargie of University College London and the University of Leeds in England, trekked into the basin to extract "cores" to measure how deep the peat went in dozens of places. Based on those long cylindrical cross sections of soil, the researchers calculated that the peat deposits found in the jungle, some as deep as 5.9 meters, boost the global estimated amount of peat in the tropics by 36 percent. Then the team used satellite data to measure the boundaries of the peat. From there, the researchers estimated that the carbon stored in Central Congo Basin's peat is equivalent to about 20 years of fossil fuel emissions from the United States, at current rates.

Other groups have quantified existing peatlands remotely. A study published in August 2017 in Global Change Biology used data on where water accumulates and how it flows across the landscape to predict where peat might be hiding in tropical regions.

The analyses suggest that South America may be home to far more peat than previously known. A network of smaller peatlands in the Amazon Basin adds up to 629,000 square kilometers, an even larger area than the Congo find, says study coauthor Louis Verchot of the International Center for Tropical Agriculture in Cali, Colombia. This newfound South American peat plus the Congo area and some new finds in Asia boost known tropical peatlands from 440,000 square kilometers to 1.5 million.

Logging and mining already threaten the carbon stored in the trees of tropical forests. The peat-rich soil has value as well.

Where's the peat?

Out of balance

When dug up, peat is inherently flammable and is used in some places as a source of fuel. But in their natural, wet state, peatlands are resistant to fires. Even after months of drought, healthy peatlands stay moist. So scientists are trying to understand what factors change that dynamic - and what that means for fires and carbon storage.

It can be hard to test the effect of drying over time in a controlled way, but in one instance, Turetsky got lucky. In 1983, part of a fen, or marshland, in Alberta, Canada, was drained for a forest management project. The water table dropped roughly a quarter of a meter, a moderate amount. Eighteen years later, a wildfire burned in the area.

Turetsky and colleagues saw an opportunity for a natural experiment to answer a few open questions. The researchers tracked how drainage followed by fire affected the peatland over time, compared with areas that burned but weren't drained or parts that were drained but didn't burn.

The drained area was far more vulnerable than the undrained area to big changes after a fire, the researchers reported in 2015 in Scientific Reports. The combination of drainage and wildfire invited different plant species to move in over the next decade. The new plants changed the ecosystem from fire-resilient to one that was liable to burn again and again. And the leafy canopy of the broadleaf trees that took up residence in place of the once-dominant black spruces blocked out the sunlight necessary for peat-producing mosses to return.

The change Turetsky saw, from a fairly modest disturbance, was much bigger than she expected. She knew that completely drying out such a landscape would make it extremely fire-vulnerable - dramatic changes like those seen in Southeast Asia. But the change in the Alberta fen was much smaller, and yet still had a substantial effect.

Compared with areas that hadn't been drained, the areas that had been drained lost almost 500 more years' worth of accumulated peat, she says. (She calculated the figure based on the amount that burned and the rate at which peat accumulates.) That's 500 additional years of locked-away carbon released back into the atmosphere in a matter of weeks.

Farming's future

Draining the land plus "slash and burn" techniques to clear areas for agriculture are the main reasons that tropical peatlands are catching fire, says Alexander Cobb, an environmental scientist at the Singapore-MIT Alliance for Research and Technology. To make room for oil palm plantations and other crops, companies will raze existing trees (the source of future peat) and drain the water to dry out the soil.

In 2017, 139 scientists signed a letter to the editor in Global Change Biology arguing that draining tropical peatlands for agriculture is unsustainable. Denying the effects that agriculture has on these landscapes will have long-term consequences, such as more frequent and more devastating fires, the researchers wrote.

Now, Indonesia is working to restore its peatlands. It's not as simple as prohibiting crops in peat-rich areas, though. In densely populated island nations, space is at a premium and people still need to eat, says Susan Page, a tropical bog expert at the University of Leicester in England and one of the letter's signers. Solving the problem might require finding crops that can grow in soggier soil so bogs wouldn't have to be drained. But solutions are a long way off.

"A lot of the economic support for alternative crops doesn't really exist yet," Page says. "We're in the in-between stage of knowing we want crops but not having a suitable list of species."

Even in places where peatlands are protected from agriculture, there are other potential threats. Cobb and colleagues spent months figuring out how to bushwhack through dense trees with exposed roots as tall as a human to reach a rare, untouched peatland in Brunei, a small, wealthy Southeast Asian nation that Cobb says has been more proactive about protecting its peatlands than neighboring countries. The researchers plunged measuring devices into the soil to determine the depth of peat and how wet it was. With those data, the team created a model of the way rainfall affects the amount of peat that can build up in any particular place, published last June in Proceedings of the National Academy of Sciences.

The conclusion: Along with total rainfall, timing of that rainfall matters. If rainfall becomes more irregular, as it's predicted to in the future, "then with the same average rainfall, the peatland can support less peat," Cobb says.

Safe if frozen

Land of ice and fire

Peatlands in cold places face challenges in a changing climate, too. In northern latitudes, including the Arctic, peat has been entombed for centuries in permafrost. Arctic warming is now exposing that peat, raising the risk of once-uncommon fires.

Last summer's Greenland fire is one such example. When McCarty spotted what she thought was a fire, she posted the satellite data on Twitter. Over the coming weeks, she and other scientists virtually checked in on the fire multiple times each day, becoming convinced that the smoke was fueled by peat.

For one thing, there's very little vegetation in the region that could provide fuel. Peat in the soil was one of the few options. Plus, the fire lingered for several weeks, but barely traveled. That's very characteristic of a peat fire, McCarty says. If the fire's not moving, it's probably smoldering, slowly burning through dense organic matter with a lot of smoke and minimal flames.

Scientists have not scoped out the Greenland fire site in person, says Guillermo Rein, a fire scientist at Imperial College London. But he's part of a team that's trying to organize an expedition to the remote area, to study the soil and confirm that peat was the fire's main driver.

Arctic peat has what Rein calls "dormant flammability." That is, when it's frozen, it's safe. But if the permafrost begins to thaw, these long-entombed carbon stores are exposed to the air and suddenly vulnerable to burning.

It would be easy to dismiss the Greenland fire as a one-off event, a fluke. But really, it's just one match in a whole box. Peat blazes have been recorded in Alaska and Siberia, as well as across Canada. Evidence suggests that fires like these will become more common. The National Oceanic and Atmospheric Administration's annual Arctic Report Card, released December 12, showed that ground-level air in the Arctic is warming twice as fast as the global average surface air temperature. By the end of this century, carbon release from Arctic burning is likely to quadruple, according to a 2016 study in Environmental Research Letters. Plus, fires and permafrost thaw can start a feedback cycle that hastens future thawing, McCarty says.

The precise long-term consequences of such thawing on peat stores in the Arctic are still unclear. While peat emerging from frozen permafrost initially dries and cracks, the area might eventually flood and rewet as ice melts elsewhere, according to a 2015 paper in Scientific Reports. But until then, the dried-out peat is a fire risk.

These Arctic and high-latitude peat fires might not immediately affect as many people as tropical peat fires, because for the most part the fires aren't in agricultural hot spots or urban centers. But the global consequences, in terms of carbon release, could be just as severe.

Some researchers expect that as climate change pushes agriculture and human populations farther north, "people are going to come more in contact with these mostly pristine landscapes" and disturb them in ways that could increase fire risk, Page says. In Canada, she says, "decades down the line, we could see a similar fire dynamic as we're seeing in Southeast Asia" - uncontrolled fires causing irreparable damage to long-term carbon stores.

"There's more and more talk in the north about draining northern soils," Turetsky adds. "We already know what's going to happen."

This article appears in the March 17, 2018 issue of Science News with the headline, "Smoke Signals: Burning peatlands have environmental researchers on alert."

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When bogs burn, the environment takes a hit

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In 2015, massive wildfires burned through Indonesia, sending thick smoke and haze as far as Thailand. These fires were "the worst environmental disaster in modern history," says Thomas Smith, a wildfire expert at King's College London. Smith estimates that the fires and smoke killed 100,000 people in Indonesia and neighboring countries and caused billions of dollars in damage.

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Higher Carbon Dioxide levels are effecting the vitamin levels in ride paddies.

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By the end of this century, rice may not deliver the same B vitamin levels that it does today. Protein and certain minerals will dwindle, too, new data suggest.

Testing higher carbon dioxide concentrations in experimental rice paddies in China predicts losses in four vitamins - B1, B2, B5 and B9 - an international team reports May 23 in Science Advances. Adding results from similar experiments in Japan, the researchers also note an average 10.3 percent decline in protein, an 8 percent fall in iron and a 5.1 percent fall in zinc, supporting previous studies of rice and other crops ( SN: 4/1/17, p. 14). Two bright spots: Vitamin B6 levels remained unchanged and vitamin E increased.

In experimental setups nicknamed FACE (free-air CO₂ enrichment) in China's Yangtze River delta and near the Japanese city of Tsukuba, researchers grew a total of 18 varieties of rice. Piping exposed the rice to CO 2 concentrations elevated to 568 to 590 parts per million - higher than the current level of 410 ppm, but in line with the current trend toward 570 ppm in this century.

The nine rice varieties from China, from three years' crops and analyzed in their unrefined brown form, differed in degree of vitamin loss. On average, B1 levels (thiamine) declined 17.1 percent; B2 levels (riboflavin), 16.6 percent; B5 (pantothenic acid), 12.7 percent; and B9 (folate), 30.3 percent.

Such declines in rice nutrients could hit economically strapped populations in Asia the hardest. Nine of the world's 10 most rice-dependent countries are in Asia. (The other is Madagascar.) The researchers predict that about 600 million people currently without good options for switching diets could risk nutrient deficiencies from rice declines. B vitamins help with a range of bodily tasks, from maintaining a healthy brain to enabling normal fetal development.

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As CO2 increases, rice loses B vitamins and other nutrients

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By the end of this century, rice may not deliver the same B vitamin levels that it does today. Protein and certain minerals will dwindle, too, new data suggest. Testing higher carbon dioxide concentrations in experimental rice paddies in China predicts losses in four vitamins - B1, B2, B5 and B9 - an international team reports May 23 in Science Advances.

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As CO2 levels continue to rise—we’re on track to double pre-Industrial levels in the next few decades—it might sound like we’re in for a vegetational boom.

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Any middle-schooler groks the fundamentals of photosynthesis: Fueled by sunlight, plants turn carbon dioxide and water into sugar and oxygen, which they use to grow stems, roots, leaves, and other tasty bits. As CO ₂ levels continue to rise-we're on track to double pre-Industrial levels in the next few decades-it might sound like we're in for a vegetational boom. But any greenery growth spurt will come with a downside. CO ₂-charged sprouts contain more starches and sugars, and fewer minerals and proteins. You can try to avoid junk food, but our plants are getting junkier too.

See, plants also require proteins in order to grow, which they synthesize using elements they draw from the soil, such as nitrogen, phosphorus, and potassium. In the course of sucking up those molecules, greens also take in nutritious minerals like zinc and iron. Plants often absorb more than they need, storing the excess in their cells. Then humans get to eat them.

Agronomists, however, have recorded a steady decline in some of those minerals, proteins, and vitamins for half a century. For example, USDA data shows that kale from 1999 had 23 percent less iron than 1950s greens did. Historically, scientists have blamed industrialized farming for practices like overworking soil, which strips it of the good stuff.

But now the blame is shifting to include CO ₂. In 2002, mathematician Irakli Loladze theorized that photosynthesis requires fewer proteins as CO ₂ climbs, which means plants acquire fewer incidental micronutrients while sucking them up-skewing the ratio of healthy to unhealthy content. He recorded an 8 percent nutrient drop, on average, in certain kinds of crops, including rice and wheat.

In 2014, Loladze and another group of scientists both published research lending weight to his earlier hypothesis. The two studies drew upon more than a decade of data from agronomists, who had planted 41 varieties of six food crops-wheat, maize, sorghum, field peas, soybeans, and rice-and surrounded part of each field with nozzles blasting enough CO ₂ to warm any greenhouse. Analysis of the harvests showed maize and sorghum fared fine, but rice-a staple for half of humanity-lost about 3 percent of its zinc; that could put hundreds of thousands, if not millions, of people at risk of deficiency, leaving them more vulnerable to respiratory diseases, diarrhea, and malaria.

If current trends continue, global atmospheric will match those experiments within the next 50 years. When that happens, researchers estimate that hundreds of millions-mostly pregnant women and children living in poverty-could end up short on essentials such as iron, protein, and, yes, zinc. Plus, there's a chance these extra-sugary plants will contribute to an uptick in diabetes-which is already one of the world's top killers.

Unless we go cold turkey on our carbon habit (not likely!), we'll need to focus on finding even-more-nutritious grain varieties. Those crops would still suffer the consequences of too much CO ₂, but they might keep our diets healthy long enough for us to clean things up.

This article was originally published in the Summer 2018 Life/Death issue of Popular Science.

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Carbon emissions are sucking the nutrition out of our food

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Any middle-schooler groks the fundamentals of photosynthesis: Fueled by sunlight, plants turn carbon dioxide and water into sugar and oxygen, which they use to grow stems, roots, leaves, and other tasty bits. As CO 2 levels continue to rise-we're on track to double pre-Industrial levels in the next few decades-it might sound like we're in for a vegetational boom.

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No GMOs have been linked to causing health issues but you should still avoid them. People can avoid them although it could be difficult.

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While there's currently no evidence that genetically modified organisms harm human health, that isn't to say there aren't legitimate reasons to avoid them.

Perhaps the most common is a simple preference for that which is natural and a general aversion to that which technology-especially technology developed by Big Ag-has meddled in. Others worry about long-term effects that haven't appeared in scientific studies yet, or ecosystem-level impacts that we haven't picked up on. A comprehensive 2016 report from the National Academies of Science, Engineering, and Medicine found no evidence that would support those concerns, but it also noted that caution is generally a good idea.

GM experts and proponents also have legitimate concerns that adding a label identifying GMOs gives the impression that there are scientifically proven risks to worry about. Studies on perception of GM food suggests that the public has a baseline aversion, and a label may increase wariness. Labeling advocates, of course, argue that if Americans want to avoid GMOs, they have a right to do so.

But really, a lot of the research on public opinion of GM food suggests that Americans don't so much think negatively of it as that they don't think much about it at all. Yes, there's a baseline aversion, but the opinion of study subjects seems to vary wildly depending on the information provided. One study following up on that 2016 report found that the entire American public shifted their opinion measurably in the positive, likely because the report was well-publicized in its findings that GMOs are, as far as we can tell, perfectly safe for the human body.

So, it's unclear how many Americans will actually be looking to avoid GM food in the future. But even if you want to keep your pantry GMO-free, doing so could prove challenging.

"Can people avoid them? The answer is certainly yes. Especially in the last few years there have been more products on the market that are non-GMO or organic," says Jayson Lusk, an economist at Purdue University who studies the consumer side of GMOs. "Now, those products are more expensive-no one ever said you can avoid them for free. But they can if they're willing and able to pay, and one way they'll pay is in the time to find the products."

Though very few fruits and vegetables are genetically engineered, he points out that almost anything with corn or soybeans will be difficult to get without a GM component. More than 90 percent of both crops are bioengineered in the U.S., and corn and soy derivatives go into many processed foods. Much of the sugar produced derives from sugar beets, nearly all of which are genetically engineered. Somewhere between 60 and 70 percent of processed foods on the market today have a GM ingredient, but many of those foods may not require a label according to the proposed rules.

Highly processed ingredients like high fructose corn syrup have little to no traceable DNA in them, and so the U.S. Department of Agriculture (which regulates food labels) doesn't require manufacturers to add a label to indicate those bioengineered foods.

And then there's that word-"bioengineered." The USDA only just announced how they would require manufacturers to disclose GM ingredients, though the law was enacting back in 2016, and the new rules don't use the term "GMO" or even "GM." Instead, they opt for "BE" or "bioengineered," perhaps to avoid using loaded terminology. "I'm not sure how much people will know that term," says Dominique Brossard, a communications professor at University of Wisconsin-Madison specializing in life science issues like GMOs. "I don't think it's going to be very easy for people to find out [which foods are genetically modified]."

"I think this was actually the intent of the 2016 law," says Glenn Stone, an environmental anthropologist who studies the GMO debate. "[It] was passed just in time to overrule a state-level law was taking effect requiring that GMO foods have clear labels." Vermont had previously passed legislation that would have fined companies for failing to label food containing GM ingredients, including highly processed ones like corn syrup (though it excluded cheese, which often relies on a genetically engineered enzyme called chymosin). It also specified that the labels would include the phrase "genetic engineering," not "bioengineered."

In contrast, the USDA regulations allow companies to choose between three options: write out the warning (as in "contains a bioengineered food ingredient"), include a BE label, or use a QR code that would link the consumer to a page disclosing all the information.

Stone, along with other labeling proponents, argue that these options will make it harder for people to actually get the information the legislation is supposed to mandate. "This rule claims to label GMO foods, but it exempts the most common GMO food ingredients like soy oil and corn syrup while allowing the use of QR codes," he says, "knowing perfectly well that few shoppers have the time or inclination to get out their phone, scan a code, and read a website over and over while shopping."

Unless those regulations change, though, it could be quite hard to figure out exactly which foods contain GM ingredients and which do not. Many of the top GM crops grown for human consumption-maize, soybeans, canola, sugar beet, papaya, squash, eggplant, potato, and apples-get processed first, and wouldn't require a label. The rest, if sold whole or as part of another food, would necessitate one. A recent overview of attitudes towards GM foods, published in the journal Annual Reviews, commented that "Since soybeans and corn (the most widely planted GE crops) are common ingredients in many food products (corn starch, corn syrup, corn oil, and soybean oil), it is likely that foods in the United States listing soybeans and corn as ingredients contain some GE ingredients unless it is specifically stated that they do not."

Avoiding GM foods entirely could mean quite a drastic shift away from any processed food at all. Corn syrup and soybean oil are in a surprising number of foods, and they won't carry a BE label. It'll be up to you as the consumer to navigate those grocery store aisles on your own.

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Avoiding GMO food might be tougher than you think

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While there's currently no evidence that genetically modified organisms harm human health, that isn't to say there aren't legitimate reasons to avoid them. Perhaps the most common is a simple preference for that which is natural and a general aversion to that which technology-especially technology developed by Big Ag-has meddled in.