News this Week

Science  13 Nov 2015:
Vol. 350, Issue 6262, pp. 722
  1. This week's section

    Ice volcanoes on Pluto's surface

    PHOTO: NASA/JOHNS HOPKINS UNIVERSITY APPLIED PHYSICS LABORATORY/SOUTHWEST RESEARCH INSTITUTE

    Researchers with NASA's New Horizons mission have discovered evidence on Pluto for two cryovolcanoes—volcanoes built of frozen ice that once oozed molten ice from the inside of the dwarf planet. The discovery of the two features—provisionally named Wright Mons (pictured, at center) and Piccard Mons—was announced on 9 November at a meeting of the American Astronomical Society in National Harbor, Maryland. It suggests that at some point in Pluto's past, it had a heat source that melted interior reservoirs of volatile ices, such as nitrogen and methane, which later erupted at the surface. The rims of the cryovolcanoes tower as much as 5 or 6 kilometers high and are more than 150 kilometers across, encircling pits that are nearly as deep as the mountains are tall. “When you see a big mountain with a big hole on the top, it generally points to one thing,” says Oliver White, a New Horizons scientist at Ames Research Center in Mountain View, California. Possible ice volcanoes have been spotted on Triton, a moon of Neptune, and Titan, a moon of Saturn, but Pluto's cryovolcanoes dwarf them all, White says. http://scim.ag/cryovolcanoes

    Brazilian birds to return home

    A Qatar-based breeding program aims to return rare Spix's macaws to the Brazilian forest.

    PHOTO: © PATRICK PLEUL/DPA/CORBIS

    Believed to be extinct in the wild since 2000, the bright blue Spix's macaws (Cyanopsitta spixii) may soon return to the dry “caatinga” forest of northeastern Brazil, thanks to an international effort to return the species to its original habitat. Brazil currently has only 12 specimens in captivity. Now, after years of informal cooperation, the Brazilian government signed an agreement last month to exchange some of its birds with a private collection at the Al Wabra Wildlife Preservation facility in Qatar to aid in both breeding and reintroducing the captive birds. Two older female “ararinhas” from Brazil were sent to Qatar to be artificially inseminated, and a male-female pair was sent to Brazil on 26 October to flock with other youngsters. The aim is to mix bloodlines to improve fertility in the population and produce viable offspring to be released into the wild, possibly as early as 2018. “It's time to send these birds back to nature,” says ornithologist Pedro Develey of SAVE Brasil in São Paulo, part of the conservation partnership BirdLife International.

    New rocky exoplanet in nearby orbit

    An array of robotic telescopes spotted the Earth-sized rocky exoplanet.

    PHOTO: JONATHAN IRWIN

    Exoplanets may be two a penny these days—nearly 2000 have been confirmed—but one recent discovery is causing a frisson of excitement. GJ 1132b, as it is known, is truly Earth-sized, only 16% bigger in diameter and about the same density as Earth, suggesting a similar rocky crust and iron core. It's orbiting a relatively small, dim star—the most abundant sort in the galaxy. But what makes it particularly noteworthy is its distance, a mere 39 light-years from Earth—a stroll down the street in astronomical terms. Astronomers gather data from exoplanets when they transit in front of their star, revealing their size, and, to an extent, the composition of their atmospheres. Bright stars generate a lot of “noise,” drowning out that signal. With the feeble light from its star, its proximity to Earth, and its close-in orbit—providing a transit once every 1.6 days—GJ 1132b could soon be the most-studied exoplanet in the heavens.

    “Show us some data that this is ready for prime time.”

    Eric Topol, director of the Scripps Translational Science Institute in San Diego, California, to STAT on geneticist J. Craig Venter's Health Nucleus facility, which would charge $25,000 to assess health by sequencing a person's genome and performing a whole body scan.

    By the numbers

    $1 million—Prize money awarded by the nonprofit forum TED to archaeologist Sarah Parcak (http://scim.ag/TEDgrant) to investigate the looting of ancient Egyptian sites with the help of satellite technology.

    $1 billion—Amount of money Toyota will invest in artificial intelligence to create a “guardian angel” for drivers over the next 5 years, via their new Toyota Research Institute.

    1377—Number of physicists awarded the Breakthrough Prize in Fundamental Physics this year. Five teams of researchers were recognized for their research on neutrinos, the cosmos's most mysterious subatomic particle.

    Around the world

    Geneva, Switzerland

    Sierra Leone defeats Ebola

    Ebola has infected at least 8794 people in Sierra Leone, 40% of whom have died from the disease, but transmission of the dreaded virus officially came to an end on 7 November. Sierra Leone recorded its first confirmed cases in May 2014. Now, 42 days after two separate blood tests on the last confirmed case of Ebola came back negative, the World Health Organization has declared the epidemic in Sierra Leone over. Liberia was declared Ebola free on 3 September, but in parts of the third affected country, the epidemic continues: Guinea recorded one confirmed case, a newborn, during the week that ended 1 November. The baby's mother died from the disease, and two of her other children have tested positive, too.

    Ottawa

    Trudeau fulfills science pledges

    Canada's Prime Minister Justin Trudeau moved quickly after taking power on 4 November to fulfill his campaign promise to give science and evidence more weight in his government. He appointed two ministers with “science” in their titles: Kirsty Duncan, a medical geographer from the University of Toronto, is minister of science and will focus on supporting basic research. Veteran politico Navdeep Bains is minister of innovation, science, and economic development, and will focus on getting industry to boost applied R&D. Cheering social scientists, Bains immediately reinstated the mandatory long-form census, canceled by the previous government in 2010. He also unmuzzled government scientists, announcing that they were free to speak about their work with the media and the public without prior permission from their communications offices.

    Washington, D.C.

    Climate change linked to extremes

    Continuous rains left Jakarta flooded in February.

    PHOTO: © REYNOLD SUMAYKU/DEMOTIX/CORBIS

    A new report by National Oceanic and Atmospheric Administration scientists, published last week in the Bulletin of the American Meteorological Society (BAMS), holds climate change accountable for some of 2014's abnormally intense weather events. In an effort to sort out the roles of human-caused climate change and natural fluctuations in last year's global weather, scientists investigated 28 severe climate events. About half were directly linked to human-caused climate change—among them monsoon-triggered flooding in Jakarta, a record heat wave that scorched the Koreas and China in May, and the Himalayan snowstorm in October. The BAMS report also provides substantial evidence that climate change is ramping up the likelihood and intensities of heat extremes across the globe, as well as the likelihood of California wildfires, although the report didn't find a specific link to the fires that raged in California in May and September.

    Washington, D.C.

    Manhattan Project a national park

    Some 70 years after the United States's Manhattan Project produced the first nuclear weapons, the project is slated to become a national park at three related sites. The 2015 National Defense Authorization Act, signed by President Obama in December 2014, authorized a Manhattan Project National Historical Park. This week, Department of Energy Secretary Ernest Moniz and Department of the Interior Secretary Sally Jewell officially established the park with the signing of a Memorandum of Agreement that defines the agencies' respective roles in its creation and management. The park's three locations will be at Oak Ridge, Tennessee, the site of the project's pilot plutonium plant and a uranium enrichment plant; Hanford, Washington, the site of a plutonium production plant; and Los Alamos, New Mexico, where scientists labored to produce the atomic bomb.

    London

    Urge to boost science funding

    With a nervous eye on the United Kingdom's next 4-year funding allocation, to be announced on 25 November, the Science and Technology Committee of the House of Commons this week criticized the government's track record in research funding and called for a strategy to increase it. This summer the government set a goal of cutting ministry budgets by up to 40%. The United Kingdom puts 1.7% of its gross domestic product into R&D, less than the United States (2.8%) and Germany (2.9%), and well below the 2.4% average for developed countries. “The U.K. risks losing its status as a world leader in research,” said committee chair Nicola Blackwood in a statement. Meanwhile, on 6 November, the United Kingdom's Department for Business, Innovation & Skills, the main government funder of research, proposed simplifying its system of university grants by eliminating the Higher Education Funding Council. The department also suggested lessening the administrative burden of its Research Excellence Framework, a massive evaluation of universities for funding purposes. The department will accept comments until 15 January.

    Brussels

    Top scientists fill E.U. advice gap

    Seven scientists, including a Fields medalist and the director of CERN, Europe's premier particle physics lab, were appointed on Tuesday to advise the European Commission. This brings an end to a year of suspense since the awkward exit of Scottish biologist Anne Glover, the first and only chief scientific adviser in the commission's history. The group will rely on a team of 25 within the research directorate—up from five staff members on Glover's former team—and will be part of a larger setup to draw advice from other sources across Europe, including learned societies. “I think this format is basically a step up from what existed before in terms of resources,” research commissioner Carlos Moedas told Science. This new Scientific Advice Mechanism is “a robust solution” that is better suited to the E.U. institutions than a single appointee, he added. http://scim.ag/ECsciadvisers

    Newsmakers

    Potti found guilty of fraud

    Perhaps ending a long-running saga, federal officials have declared former Duke University cancer researcher Anil Potti guilty of research misconduct. On 9 November, the Office of Research Integrity (ORI) concluded that Potti falsified data in nine papers, a manuscript, and a grant application claiming that certain gene signatures could predict a patient's response to chemotherapy. After Potti published several high-profile papers in 2006, outside biostatisicians raised questions about his work. Duke began formally investigating in 2010. Potti left Duke that year, and Duke later faced a lawsuit from patients in clinical trials based on Potti's studies. As part of a voluntary settlement, Potti “neither admits nor denies ORI's findings of research misconduct.” If he seeks federal funding again, his research must be supervised for 5 years. http://scim.ag/_Potti

    The Science News Quiz

    This question stumped our online readers this week. Can you outdo them? When tropical Cyclone Chapala hit Yemen early last week, how much rain fell?

    Take the quiz—and find out the answer—here: http://scim.ag/1MH9WU5

  2. Oceans and Climate

    Ghosts of oceans past

    1. Warren Cornwall*

    Studies of fossil coral reefs exposed at an amusement park in Mexico suggest a rapid rise in sea level some 120,000 years ago, during a warm spell in Earth's history.

    PHOTO: © KEN GARRETT

    Andrea Dutton's hunt for ancient coral reefs has taken her from white sand beaches along the Indian Ocean to wave-beaten cliffs beside the Caribbean. But the geologist's strangest field trip may have come last year, when she spent days at a Mexican amusement park carved from the seaside jungle of the Yucatán Peninsula.

    Dutton was not there for the water rides and wild animal exhibits. She had made the trek from her lab at the University of Florida in Gainesville to sample the rocks that the park's builders had cut and exposed: the remains of coral reefs more than 100,000 years old. Dutton was stunned by the star and staghorn corals preserved in the outcrops—including a mosaic of fossils in the walls of an underground room next to a jaguar pen. “It was the most amazing exposure to a reef of that period that I have ever seen, or ever will,” she recalls.

    Dutton seeks out ancient reefs to understand what's in store for Earth's coastlines. She's one of a small cadre of scientists scouring the planet for evidence of how high the oceans rose when polar ice melted during previous global warming spells. The jaguar pen's fossil reefs, for instance, are providing insight into one past episode of sea level rise, driven by the decline of ice sheets in Greenland and Antarctica more than 125,000 years ago.

    Accurately measuring ancient sea levels has proven to be difficult work. But by marrying gritty fieldwork with computer models, Dutton and others are showing with increasing certainty that the sea was many meters higher at times when the past climate was only slightly warmer than today. The results are providing important—and sobering—evidence for how high the seas might climb in the future.

    “There are a lot of things I'm uncertain about as a scientist,” says Dutton, one of the leaders of PALSEA2, an international effort by scientists to nail down the details of ancient sea levels. “But we're certain sea level is going to keep rising” with the extra heat already added to the climate in recent decades. “And not just a little bit. We've got a long way to go.”

    TO REACH THAT CONCLUSION, sea level researchers have focused on three periods when fossil and chemical evidence indicates that slight wobbles in Earth's orbit, sometimes abetted by elevated levels of atmospheric carbon dioxide (CO2), triggered global temperatures that were as warm or warmer than today. Some 3 million years ago, global temperatures were 1 to 2 degrees above modern levels and CO2 levels were about the same as today's 400 parts per million (ppm). In more recent episodes, some 125,000 and 400,000 years ago, the world was close to today's temperatures, but CO2 levels were likely far lower, at about 250 to 300 ppm (see graphic, p. 755).

    In the early 2000s, when Dutton first began trying to gauge past sea levels during these periods, some scientists still simply measured how high an ancient shoreline—a beach turned to sandstone, for example, or rocks holding fossils of corals or mollusks—sits above today's sea level. They would date the outcrop, and announce how high the ocean's surface once stood.

    Geologist Andrea Dutton examines fossil corals, such as these reefs in Florida, as part of her studies of past sea levels.

    PHOTO: © MAGGIE STEBER

    The results were sometimes a mess. For instance, when scientists sought to determine what the sea level was 400,000 years ago, shorelines at some sites suggested it was as much as 9 meters higher than today's. But on several islands—Bermuda and the Bahamas—the evidence suggested a difference of as much as 21 meters. The sea could only have risen that high if much of East Antarctica's ice sheet, the world's biggest single mass of ice, had melted. Some scientists doubted that scenario, arguing that the high-standing beaches and corals were a fluke, perhaps created by a giant ancient tsunami.

    In fact, a dizzying number of things can cloud efforts to use the past as a crystal ball. The chemical makeup of fossil coral changes over time, making it tricky to calculate its age. There's uncertainty about the depths at which corals grew, complicating efforts to estimate past sea level from an ancient reef 's current height above the sea. Ice sheets can be so massive that their sheer gravity drags the ocean's water closer to them; when ice sheets are at their maximum, nearby seas are unusually high, whereas other places are below average, potentially skewing estimates of sea level around the globe. And heavy ice sheets can dimple the crust under them, while nearby land bulges upward. As Jerry Mitrovica, a geophysicist at Harvard University, puts it, Earth “is dynamic, it's evolving. And that's what distorts this lens.”

    In the last few years, Maureen Raymo, a marine geologist at Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York, has learned just how maddening these complications can be. In 2009, she teamed with scientists from four other universities to figure out how high seas rose during the Pliocene, some 3 million years ago. That's an era scientists are particularly interested in, because CO2 in the atmosphere then mirrored modern levels. Initially, Raymo expected to gather precise elevation measurements along hundreds of kilometers of ancient shorelines on several continents, adjust for the weight of past glaciers, and then emerge with a fairly precise estimate of sea level.

    “That did not happen,” Raymo recalls. The measurements were “all over the place.”

    That's when she learned the importance of one more factor, called dynamic topography. The geologic drama of Earth's tectonic plates is usually associated with earthquakes and fault lines. But massive sections of the planet's crust can also slowly tilt back and forth, rocking like rafts on the ocean. In the United States, for instance, the southern part of the eastern seaboard has been gradually rising relative to the northern part. Ancient shorelines in the southern region may have been uplifted by as much as 60 meters over the past 3 million years, according to one estimate.

    For Raymo, that dynamic lift made one of her main research targets—a 900-kilometer-long ancient shoreline running from Georgia to Virginia—nearly unusable. Don't believe “anyone who tells you they know the Pliocene sea level to within 10 meters,” she says.

    FOR PERIODS MORE RECENT than the Pliocene, however, answers are coming into focus with the help of sophisticated computer modeling. In 2012, for example, Raymo and Mitrovica argued that astonishing high-end numbers for sea level rise 400,000 years ago, from Bermuda and the Bahamas, were largely an illusion created by the weight of ice from an earlier ice age. Bermuda and the Bahamas sat on a spot that had bulged upward during the ice age and sank afterward, they concluded. After adjusting for the effect, they pegged sea level at 6 to 13 meters above today's. Since then, observations in South Africa have pointed to an even narrower range of 8 to 11.5 meters, according to a 2014 study in the Journal of Climate.

    Along with computer models, studies done in places far from the influence of ice sheets have helped to sharpen the view of the past. Dutton, for example, headed to the Seychelles islands, 1500 kilometers off Africa's eastern coast in the Indian Ocean, to survey shorelines from 125,000 years ago. Besides being geologically quiet, the islands have ancient corals that grew vertically up the sides of rocky outcrops, providing a relatively easy-to-read yardstick of changing sea levels. (Then there are the palm trees and the silky soft beaches. “You have to choose your profession very carefully,” Dutton jokes.)

    Looking backGRAPHIC: A. CUADRA/SCIENCE

    Other researchers are trying to directly measure the major contributor to past sea level rise: losses of polar ice. This month, a team led by John Stone, a geologist at the University of Washington, Seattle, is scouting a place to drill into the bedrock beneath ice sheets in West Antarctica's Pirrit Hills. Their goal is to find radioactive isotopes generated by the rock's exposure to cosmic rays. The presence of the isotopes would indicate that the ice had once vanished there, exposing the bedrock. And because the isotopes decay into other elements at a predictable rate, the researchers hope to use them as a clock that shows when the ice melted. “I really do think we're going to end up knowing something significant once we get these cores,” Stone says.

    ALREADY, the sea level findings indicate that it may not take much more warming to melt large parts of major ice sheets. Current forecasts suggest a bump of up to 4.8°C by 2100 could lift sea levels by as much as a meter—exposing many coastal communities to serious threats from erosion and flooding. But clues from multiple past warm periods indicate that over time, ice sheets are sensitive to even smaller temperature increases, Dutton says. She was lead author of a study in Science this year that noted modern temperatures are close to those 125,000 years ago, when the sea level likely was 6 to 9 meters above today's.

    “That suggests … we've warmed [our climate] so rapidly that the ice sheets are out of equilibrium. And they're playing catchup,” she says.

    For societies today, though, the biggest question may not be how high the sea ultimately rose during past warmings, but how quickly it happened. In particular, researchers would like to know answers to two questions: Did Antarctic ice melt in sudden surges and, if so, exactly what climate conditions unleashed such an event?

    “The biggest question everyone has is, ‘eHow quickly is the West Antarctic Ice Sheet going to collapse?’” Dutton says.

    She thinks the fossil reefs in the Yucatan amusement park could help provide answers. A 2009 study of the coral's growth patterns made headlines after it concluded that, some 121,000 years ago, the sea rose as much as 3 meters in less than a century. The surge appears to have drowned one reef, setting the stage for the growth of a second, higher reef, says Paul Blanchon, the study's lead author and a geologist at the National Autonomous University of Mexico's Institute of Marine Sciences & Limnology in Puerto Morelos.

    Dutton has doubts about that scenario. She thinks it's possible the estimates were thrown off because the land was sinking as North American glaciers receded.

    To get a clearer picture of how fast sea level rose, she would like to return to the Yucatan, as well as to reefs in Australia and Florida. She hopes to drill meters-long reef cores recording past changes in sea levels that can be dated, much as tree rings record past weather. A core where all the coral is close to the same age could indicate that water rose quickly at that time, forcing the coral to grow rapidly upward. A single core with corals spanning thousands of years would indicate a gradual change.

    But given the difficulties associated with analyzing fossil corals, don't expect them to produce fine-grained estimates, such as how fast seas rose over a decade or even a century, warns Peter Clark, a geologist at Oregon State University, Corvallis. “We can talk about meters per thousand years, but I don't think we can get it any finer than that,” says Clark, one of the two top authors of the Intergovernmental Panel on Climate Change's most recent assessment of sea level science.

    Dutton hopes further work in the Yucatán could also help resolve another issue: whether seas rose quickly some 120,000 years ago, after roughly 13,000 years of warmth, as Blanchon has suggested, or soon after the warming began, as she believes. Because the climate varied even during the warm period, knowing the timing could help scientists better decipher what conditions triggered an ice sheet collapse, Dutton says. And understanding those conditions could, in turn, offer clues to the future of today's West Antarctic Ice Sheet, which is already showing signs of an accelerating retreat. “That's why this question—did it happen in the beginning or the end—[is a] first order question now,” she says.

    Answering it could require studying many more ancient shores, now perched high above seas that are, once again, on the move.

    • * Warren Cornwall is a freelance writer in Bellingham, Washington.

  3. Oceans and Climate

    Breaking the waves

    1. Gabriel Popkin*

    A marsh constructed on Pivers Island in North Carolina is helping researchers understand the costs and benefits of so-called living shorelines.

    When Hurricane Irene hit North Carolina's coast in 2011, waves 2 meters high began pounding the shore. Two properties on Pine Knoll Shores, a community on one of the state's many barrier islands, provided a study in contrasts. One homeowner had installed a concrete bulkhead to protect his yard from the sea. But the churning waves overtopped and ultimately toppled the wall, washing away tons of sediment and leaving a denuded mud flat.

    Less than 200 meters away, another owner had installed a “living shoreline”—a planted carpet of marsh grass that gently sloped into the water, held in place by a rock sill placed a few meters offshore. The onrushing water bent the marsh grasses almost flat, but their flexing stalks dampened the waves and their deep roots held the soil. After the hurricane passed, the grasses sprang back; the property weathered the storm largely intact.

    The contrast highlights how defenses inspired by nature, rather than concrete armor, can protect coastlines from battering storms, says ecologist Rachel Gittman of Northeastern University's Marine Science Center in Nahant, Massachusetts. In a study of Irene's effects, Gittman found that in hard-hit areas along the North Carolina coast, the storm destroyed or damaged three-quarters of the seawalls and bulkheads and washed away valuable soil. Yet, shores fringed by marsh grasses experienced almost no erosion, and damaged vegetation bounced back within a year. “Plants are really good at handling big storms,” Gittman says. “Bulkheads are really not.”

    Such findings are getting more attention as researchers and coastal planners confront rising seas—and possibly more powerful storms—caused by global warming. That double punch, they say, threatens hundreds of millions of coastal residents around the world and infrastructure worth trillions of dollars.

    To be better prepared, many researchers are calling on coastal nations to rethink traditional approaches to shoreline defense, which rely largely on massive earthen dikes, rock barriers, and concrete walls. Such “gray” infrastructure damages coastal ecosystems, researchers argue, and can be difficult and expensive to adapt to changing environmental circumstances. Gittman and others argue that softer, “greener” approaches inspired by marshes, oyster reefs, and other natural features (see graphic, p. 758) can do better. With clever engineering, they say, such features can provide not only cost-effective storm protection, but also healthier ecosystems able to adapt to rising seas. “When you put in a marsh,” says environmental scientist Bhaskar Subramanian of the Maryland Department of Natural Resources (DNR) in Annapolis, “you're doing good by nature.”

    Not everyone is enthusiastic. Many people feel safer behind concrete, and—given the potentially high stakes—policymakers and regulators have been reluctant to shelve time-honored engineering techniques in favor of less familiar approaches. Some researchers also worry that even supposedly green designs could harm marine ecosystems by introducing exotic species and foreign materials into underwater habitats.

    Despite the skeptics, the push to green traditionally gray coastal defenses is gaining traction. Prompted by the devastation caused by Hurricanes Katrina and Sandy, the U.S. government is bolstering research into nature-inspired coastal engineering. And a growing number of researchers around the world are evaluating which green techniques might work best—and how gray and green engineering might be combined to create layered defenses.

    “There is so much happening on this right now,” says ecologist Ariana Sutton-Grier of the University of Maryland (UMD), College Park, and the National Oceanic and Atmospheric Administration (NOAA). “We probably are at a sea change in the way we approach coastal protection.”

    FOR MILLENNIA, humans have tried to hold back the sea. In China and along the Mediterranean, archaeologists have found evidence of seawalls and other shoreline structures some 2000 years old. And as human populations have grown, so have coastal defenses. In the United States, nearly 23,000 kilometers of shoreline—some 14% of the total—is armored, Gittman and colleagues estimated in August in Frontiers in Ecology and the Environment. That proportion could grow to one-third by the end of the century, they add, if coastal development continues at its current pace.

    Armoring can have devastating ecological consequences. Rock and concrete barriers reflect rather than dissipate wave energy, causing fast-moving waters to scour the sea floor, destroying marsh and underwater grasses that nurture fish, crabs, and other sea life. Hard structures can also cut off critical flows of sediments from uplands to the coast, starving and obliterating beaches and marshes. And as global sea levels have risen by an estimated 20 cm over the past century, many marshes and beaches have become squeezed between the higher water and unmoving concrete.

    The squeeze will worsen if global greenhouse gas emissions continue unabated. Under some scenarios, modelers warn, sea level rise could accelerate to as much as 9 mm per year, driven by melting ice sheets and the expansion of warming seawater. At the same time, warming could catalyze more powerful storms, heightening the threat of wave damage and coastal flooding. Many point to the flooding that occurred in New Orleans, Louisiana, and along the Gulf of Mexico after Hurricane Katrina in 2005, and the devastation wrought by Hurricane Sandy in 2012, as examples of what the future may hold.

    The shores of the Chesapeake Bay in Maryland are among the most vulnerable in the United States: Land subsidence there is causing local sea level rise to greatly exceed the global average, making coastal areas more vulnerable to storms. In 2003, a powerful hurricane, Isabel, swept up the coast and across the Chesapeake Bay area, killing 16 people and causing $7 billion worth of damage. It also amplified one of the nation's most prominent efforts to promote living shorelines.

    Not long after the storm passed, calls began coming in from distraught land owners, recalls Subramanian of the Maryland DNR, which provides coastal protection assistance to landowners. “All the calls were: ‘My bulkhead is floating in the neighbor's property,’” he says.

    In contrast, the agency received no complaints from landowners who had installed living shorelines with the agency's help. The constructed marshes had dampened the storm waves and reduced damage, he says, just as they would in North Carolina nearly a decade later. Soon, landowners once wedded to concrete were lining up to get help building their own protective marshes.

    Today, Maryland is considered a pioneer in green coastal infrastructure. In 2008, it adopted the nation's first law requiring landowners who want to protect their waterfront to use a living shoreline unless they can prove that only a hard structure will do the trick. The state has issued permits for more than 1000 living shorelines, almost all around the Chesapeake Bay and its tributaries. Many have not only survived but thrived through storms likely to have overwhelmed traditional gray structures.

    Other states, however, have been slow to follow suit, in part because of lingering questions about the environmental impact, effectiveness, and life span of living shorelines and other nature-inspired features.

    ONE RESEARCHER trying to answer those questions is ecologist Carolyn Currin of NOAA's Beaufort, North Carolina, laboratory. The lab sits on Pivers Island, a spit of land near Pine Knolls Shore. In 2000, when lab officials had to replace a failed seawall on the island, Currin persuaded them to install a living shoreline, turning an otherwise humdrum construction job into an experiment. NOAA worked with local partners and volunteers to install bags of oyster shells off the island's shore and plant marsh grasses on a graded sand slope.

    Defending against rising seas, in gray and greenGRAPHIC: V. ALTOUNIAN/SCIENCE

    The new marsh—along with a second one built on the other side of Pivers Island using a rock sill—has allowed researchers to gain new insights into the capabilities and behavior of living shorelines. One finding is that they appear to keep pace with local sea level rise, building up soil that keeps the marsh's surface above the low tide line.

    They also have potentially valuable “cobenefits.” The artificial marshes pack away relatively large quantities of carbon, Currin and colleagues reported (this month) in PLOS ONE. And, as suspected, the rock and oyster-shell sills used to anchor such marshes support more abundant and diverse communities of fish and crustaceans—including economically important species—than do traditional concrete structures, a team led by Gittman concludes in a paper in press at Ecological Applications.

    Currin, Gittman, and colleagues also are assessing whether shorelines colonized by living oysters can provide an additional layer of defense in shellfish habitat such as North Carolina and the Gulf of Mexico. In one experiment, they have used thousands of bushels of shells to build three artificial oyster reefs off a rapidly eroding beach on Carrot Island in the Rachel Carson Reserve, not far from Pivers Island.

    On a visit to the site, ecologist Joel Fodrie waded through quiet water to the reefs. The shell piles, now about 3 years old, were already protecting the beach, trapping sediment and helping it reverse past erosion losses. Better yet, the reef was coming to life, says Fodrie, who works at the University of North Carolina's Institute of Marine Sciences in Morehead City. Tiny crabs scurried across his hands as he examined shells covered with baby oysters. The youngsters should help the reef grow both vertically and horizontally, he noted, improving its protective effects. And properly placed oyster reefs have the capacity to grow in concert with even rapidly rising seas, Fodrie, the institute's Antonio Rodriguez, and colleagues reported last year in Nature Climate Change.

    The reef project faces challenges, however, Fodrie noted. Waves have pushed some of the oyster sills toward shore and washed away some grasses that researchers had planted. But that's OK, he says. “We planned to have some things fail, so we can see where the boundaries are.”

    ALTHOUGH SOME SEE living shorelines as a return to nature, others see them as coastal hardening by another name. Retired earth scientist Orrin Pilkey of Duke University in Durham, North Carolina, who has called for limiting coastal development, has criticized many living shoreline projects along the Atlantic coast because they make heavy use of offshore rock sills to shelter the planted grasses from wave action. The sills, he says, can bury native sea grasses and make it more difficult for fish and crabs to reach intertidal marshes.

    Biologist Joel Fodrie inspects an oyster reef that researchers built to protect an eroding beach on North Carolina's Carrot Island. Within 3 years, it was colonized by oyster larvae, creating a living defense that might be able to keep pace with sea level rise.

    Pilkey also complains that a lack of regulatory oversight and scientific monitoring makes it hard to figure out what works and what doesn't. “To me the living shoreline thing is the Wild West,” he wrote in an email. “No standards, no enforcement, no real studies especially long term and an aura of environmental holiness.”

    Even living shoreline promoters acknowledge that projects can come with ecological tradeoffs. Newly constructed marshes in the Chesapeake Bay, for example, can bury sandy, near-shore habitats. “Everyone devalues flat, nonstructural bottoms,” says ecologist Donna Bilkovic of the Virginia Institute of Marine Science in Gloucester Point. “But there are lots of animals that live in those sediments.”

    Green defenses also face substantial regulatory and political hurdles. In the United States, it can often take just a few days to obtain the needed federal and state permits to build a new bulkhead, for instance, but the paperwork for nature-inspired projects can take much longer, in part because they may involve underwater components that bury shallow-water habitats and stretch into shipping lanes. Large projects can also trigger complicated mandatory cost-benefit analyses. For gray projects, economists and engineers have long known how to calculate life span and financial return, but the task can be trickier for green projects, for which the calculus includes cobenefits such as carbon storage or improved fish habitat.

    SOME COASTAL EXPERTS have concluded that combining green and gray approaches promises the best payoff, because of their complementary strengths and weaknesses: Green infrastructure is dynamic and adaptable, but can take several years to become fully established, whereas concrete works on day one. Such hybrid defenses might involve building an oyster reef or marsh in front of a concrete seawall or dike, to provide both ecological benefits and multiple layers of storm protection.

    The U.S. Army Corps of Engineers has embraced such “gray-green” thinking, and is promoting it in concert with NOAA and other institutions through an initiative called the Systems Approach to Geomorphic Engineering. The hope, says UMD's Sutton-Grier, is to “capitalize on the strengths of both approaches—you can use gray to protect green as it establishes, or green to protect gray so that [its] lifetime is longer.”

    The idea is also catching on internationally, with Korea, China, and Australia recently considering or installing combinations of marshes and hard structures. In the Netherlands, where coastal defenses are a matter of national existence, planners are introducing salt marshes and shellfish beds to help lessen storm impacts on seawalls and dikes. (Japan also considered greening its shoreline protection arsenal after the devastating 2011 tsunami, but has so far opted for even larger seawalls.)

    The success of green infrastructure, however, may ultimately depend less on governments than on the willingness of millions of individual landowners to try something new, because so much coastline is in private hands. Persuading risk-averse homeowners can be a frustrating process, Gittman says. After Hurricane Irene, she showed the landowner with the toppled bulkhead how much better his neighbor's living shoreline had performed.

    But the landowner opted to build a new concrete bulkhead instead, and then put his house up for sale. “People are stubborn,” Gittman says.

    • * Gabriel Popkin is a freelance writer in Mount Rainier, Maryland. Reporting support provided by a fellowship from the Institute for Journalism and Natural Resources. Photography by Dylan Ray

  4. Oceans and Climate

    Moveable feast

    1. Marianne Lavelle*

    Some stocks of Atlantic cod, long a mainstay of commercial fishing, have been hit hard by warming oceans, recent research suggests.

    PHOTO: © JEFFREY ROTMAN/CORBIS

    In the early 2000s, trawler crews working the Celtic Sea off Ireland noticed something unusual. Small, spiny, bright orange fish, called boarfish, began appearing in their nets in huge numbers. Previously, the intruders had been a minor nuisance; their sharp spines jammed equipment and damaged the soft flesh of more valuable species, such as cod and hake. Irritated crews tossed them overboard.

    As boarfish schools grew, however, the problem became an opportunity. Trawlers retooled to target the fish, which were turned into meal and oil. Boarfish went from trash to treasure, and they now generate more than $10 million annually for Irish fleets.

    Scientists aren't exactly sure what is causing the boarfish boom, but there is evidence that a warming ocean is playing a role. And for fishery managers, the boarfish has become one symbol of an emerging global issue: the often surprising disruptions that climate change can create in the world's fisheries, as marine populations move, flourish, and wither as a result of warming seas.

    “Climate change is pushing whole [marine] systems to a state we haven't experienced before,” says fisheries ecologist William Cheung of the University of British Columbia, Vancouver, in Canada. The reshuffling is creating challenges for scientists seeking to understand a rapidly changing ocean. It is also taxing fishery managers, who tend to view the oceans “as stable, or steady-state,” instead of preparing for change, says Richard Merrick, chief scientist of the U.S. National Oceanic and Atmospheric Administration (NOAA) Fisheries in Silver Spring, Maryland. As a result, policymakers are scrambling to build management schemes that can cope with moving fish stocks and shifting eco systems. The stakes are high, they note, given that ocean fisheries generate $195 billion annually in the United States alone and are a key food source for hundreds of millions of people.

    IT HAS LONG BEEN A CHALLENGE to manage marine populations so that the ocean keeps on giving. In the early 1600s, when English explorer John Smith arrived in Jamestown, Virginia, he famously marveled at “more sturgeon than could be devoured by dog or man.” Within a few centuries, however, people had severely depleted that species and many others.

    Slowly, fishers and scientists learned how to set more sustainable catch limits, by combining a greater knowledge of the reproductive biology of marine species with improved surveying methods and economic data. By the late 20th century, many nations had imposed extensive controls on their fishing fleets, and even struck international agreements to prevent conflicts over stocks that swam across national borders. Such rules have helped many overfished stocks bounce back. Even relatively well-informed policies, however, have often proven difficult to implement, in part because of the ocean's great natural variability. Powerful currents can change course, huge water masses can shift, and fish and shellfish populations are prone to seemingly random booms and busts.

    Now, fishery managers say climate change is making their job even more complicated. Oceans have helped moderate the impact of fossil fuel burning by absorbing an estimated one-third of the carbon dioxide that humans have added to the atmosphere, as well as much of the heat generated by greenhouse warming. But marine life is bearing the brunt of living in a giant sink for heat and carbon, which is acidifying as well as warming the waters.

    Corals, crustaceans, seagrasses, and phytoplankton are among the many groups of organisms already showing effects from warming seas, researchers say. And fish are on the move, scientists have concluded in numerous studies, including a major survey led by ecologist Malin Pinsky of Rutgers University, New Brunswick, in New Jersey. After studying more than 40 years of census data on some 350 fish species found off North America, his team concluded that some 70% of the species were shifting their ranges, or moving to deeper or shallower waters, in response to changes wrought by warming. The researchers predicted in a 2013 Science paper that “rapid range shifts will fundamentally reorganize marine communities” and could “confound traditional management approaches.”

    AN OLD U.S. COAST GUARD STATION near Tuckerton, New Jersey, now a marine laboratory, holds an eerie record of those changes. More than 1 million translucent fish larvae float in glass vials, cataloged by species and the date they were captured.

    Laboratory Director Ken Able, a biologist at the Rutgers University Marine Field Station, started methodically catching the hatchlings 26 years ago in a nearby estuary. Originally, the goal was to learn more about populations of summer flounder (Paralichthys dentatus), a much-prized catch. Ultimately, however, Able and his colleagues realized that the estuary is an ideal location for observing the transformation of the North Atlantic. Larvae spawned from Canada to the Caribbean and beyond ride to the region on two great currents—the Labrador Current from the north and the Gulf Stream from the south.

    As a result, Able's larvae library has become a record of change. Over time, southern-dwelling species, such as the Atlantic croaker (Micropogonias undulatus), have become more abundant. Northern species, including the Atlantic herring (Clupea harengus) and three-spined stickleback (Gasterosteus aculeatus), have begun to disappear.

    U.S. East Coast fishery managers are still grappling with how their approach should change to address the ebb and flow of these species, some of which is due to fishing practices rather than climate change. But the issue has become urgent for managers in the eastern North Atlantic. Over the past decade, large schools of mackerel (Scomber scombrus) began appearing in the waters off Iceland, signaling a northward expansion of the fish's range linked to warmer waters. In 2009, amid a financial crisis, Iceland unilaterally increased its mackerel catch, prompting outrage from competing fleets in the European Union and Norway, which traditionally have had rights to the majority of the catch. They complained that Iceland's expanding fishery (and another in the Faroe Islands) was imperiling their own mackerel stocks.

    Polar invasionGRAPHIC: WILLIAM CHEUNG, ADAPTED FROM CHEUNG ET AL., ICES JOURNAL OF MARINE SCIENCES 72, (10 OCTOBER 2014) © ACS

    The science underlying such claims became the focus of fierce debate, with the parties disagreeing over the size of the whole population—a key to setting safe catch limits—and whether the competing fleets were exploiting the same or distinct populations. Opponents even had trouble agreeing on what waters should be included in the mackerel's range, and how best to count the fish.

    In a bid to clarify matters, researchers have launched efforts “to make sure that they're discussing the same stocks, using the same methodology … [but] it's quite difficult to maintain a standard that compares apples to apples,” says Manuel Barange, director of science at the Plymouth Marine Laboratory in the United Kingdom.

    In the meantime, the political impasse has continued, meaning that Iceland has been setting its own catch quotas, instead of working with other nations to establish regionwide catch limits that reflect the changing mackerel distribution.

    THE MACKEREL DEADLOCK highlights the difficulty of using traditional fishery surveys to track and predict climate-induced population shifts. Current methods, including the use of dedicated research trawlers to make periodic but limited hauls, may not allow researchers to “adequately capture the future population dynamics in a changing ocean,” NOAA officials noted earlier this year in a report. What's more, “a large percentage of the ocean is not being surveyed, let's face it,” says Jeff Kaelin of Cape May, New Jersey, a commercial fishing executive and member of regional council that helps set U.S. catch quotas. That means plenty of blind spots where scientists aren't able to see and react to sometimes subtle shifts.

    To help fill the gaps, some fishery managers and fishers would like to see more systematic use of commercial fishing vessels to gather information. In the United States, for example, the South Atlantic Fishery Management Council, which sets fishing quotas in federal waters from South Carolina to Florida, is exploring the idea of equipping fishing boats to measure environmental variables, such as temperature. That would allow researchers to study how changes in those conditions affect catches.

    The bigger dream, however, is to use such information—combined with real-time data from satellites, buoys, and other platforms—to predict future marine changes, much as weather services now forecast droughts and floods. Such a capability might have enabled fishery managers in New England, for instance, to give fishers advance warning of a record ocean heat wave in 2012 that brought warm-water squid as far north as the Gulf of Maine, and caused lobster catches to rise. Local fishers were unable to take advantage of the squid windfall because there wasn't enough notice to retool their boats with the proper gear, and lobsters rotted in trucks because processors weren't ready.

    BETTER OCEAN CLIMATE monitoring systems might also help prevent fishery calamities, a recent study suggests. The collapse of cod (Gadus morhua) stocks off New England and Canada's eastern coast has been one of the most studied and debated fishery catastrophes in the world. In both nations, dramatic cod population declines since the 1980s have led officials to essentially shut down once lucrative fisheries. Researchers have long laid much of the blame on overfishing, but have suspected that changing ocean conditions—including warmer waters—also played a role.

    That idea got a major boost last month with the publication of a study concluding that rapid ocean warming appears to have catalyzed the decline of one major cod stock living in the Gulf of Maine. Satellite data show that from 2004 to 2013 the ongoing warming of surface waters in the gulf greatly accelerated, a team led by oceanographer Andrew Pershing of the Gulf of Maine Research Institute in Portland, Maine, reported in Science. Over the past decade, the Gulf of Maine became the fastest warming spot in the world's oceans, making it hard for young cod to survive. At the time, says Pershing, fishery managers didn't understand what was happening, and so allowed catch quotas to remain too high.

    The moral of the story, Pershing says, is that “as ecosystems around the world begin to encounter these conditions that are really changing, using history as your guide is not going to be very effective.” Gib Brogan, an advocate with the conservation group Oceana in Boston, says the study also underscores the need for fishery regulators to “put a buffer in [management plans] for the uncertainty that comes with climate change.”

    For more than 25 years, biologist Kenneth Able has been collecting fish larvae (below) from an estuary in New Jersey, providing clues to a changing ocean.

    PHOTO: © DREW GURIAN

    Some of the more than 1 million larvae collected by Able's group.

    PHOTO: © DREW GURIAN

    THAT'S ADVICE that Ireland's emerging boarfish fishery is trying to heed. As catches boomed—reaching 144,000 metric tons in 2010, Ireland's second biggest catch behind mackerel—European fishery managers began to worry. Nobody, they realized, knew much about the little orange fish: how many there were, how quickly they reproduced, or even how long they lived. The managers feared that unregulated fishing could wipe out the stock before the industry even established itself.

    To buy time, the E.U. fisheries commission imposed new rules that reduced catches—and boarfish captains and others began raising money to fund the needed science. In a collaboration that some fishery managers will envy, scientists conducted the first sonar surveys of boarfish schools from commercial fishing boats, with guidance from fishermen on where to find the fish. By analyzing growth rings in fish ear bones, Danish scientists determined boarfish live as long as 30 years. Biologists also calculated how quickly they reproduce, and learned that they have few natural predators. Using old fishing records and new genetic testing methods, they determined that Irish boarfish are homebodies—they didn't migrate from another location to the North Atlantic. And they realized the species has been there a long time, albeit in smaller numbers. That suggests that some change in the environment—an increased food supply, perhaps—boosted boarfish reproduction. And warming waters are a likely catalyst, many scientists believe.

    Now, E.U. fishery managers are drawing on that information to devise a long-term management plan for the boarfish. Researchers hope it will acknowledge the possibility of future ocean changes and ecosystem shifts. And the experience could become a model for how other fishing communities can work with scientists to adapt to the changes that climate change will bring, says Kari Stange, a social scientist at Wageningen University in the Netherlands.

    Stange recalls one Irish fisherman who was preparing to travel to E.U. headquarters in Belgium to discuss how the new fishery would be managed. He said: “We can't just go to Brussels and say that a lot of fishermen think there's a lot of fish out there,” Stange recalls. “They knew they had to come with science.”

    • * Marianne Lavelle is a freelance journalist in Arlington, Virginia.

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