« July 2015 | Main | September 2015 »
Some of the world’s richest longline fishing grounds coincide with key foraging areas for seabird species. Albatrosses and petrels, along with other seabirds, come into conflict with fisheries in these areas when they forage behind vessels for bait and fish waste, where they can become caught on hooks and drown. Between 160,000 and 320,000 seabirds are thought to be killed as bycatch in longline fisheries each year, including up to 100,000 albatrosses.
A juvenile winter flounder. Credit: Dave Bailey.
Researchers at the University of New Hampshire are turning to an unusual source --otoliths, the inner ear bones of fish -- to identify the nursery grounds of winter flounder, the protected estuaries where the potato chip-sized juveniles grow to adolesence. The research, recently published in the journal Transactions of the American Fisheries Society, could aid the effort to restore plummeting winter flounder populations along the East Coast of the U.S.
In addition to showing the age of a fish, much like the rings in the cross-section of a tree, otoliths carry the imprint of chemical elements found in a fish's watery surroundings. UNH graduate student David Bailey '13 and UNH faculty Elizabeth Fairchild (research assistant professor of biology) and Linda Kalnejais (assistant professor of oceanography) found that juvenile winter flounder from estuaries within 12 kilometers (about 7.5 miles) of each other share similar chemical "signatures" on their otoliths, influenced by unique geology and water chemistry from the watersheds that empty into estuaries.
Results from this study indicate that otolith chemistry can be used to trace juvenile winter flounder back to their brackish hometowns with 73% accuracy, offering scientists a new technological tool in their quest to monitor the species.
Winter flounder -- known on the menu as flounder, sole and lemon sole -- is a fishery valued at nearly $10 million in 2013. Yet their populations along the East Coast have plummeted in the last two decades, and despite strict regulations that have limited fishing pressure, their numbers are not rebounding, says Fairchild. Many estuaries, the nursery habitats of winter flounder, are experiencing warming waters and land development pressures that may affect the number of juveniles that can survive and make their way out to deeper offshore waters, she explains.
"We don't know where the adults actually come from, which specific bay," Fairchild says. "We wanted to know if we could say, yes, that's a Great Bay fish, or that's a Narragansett Bay fish, or a Boston Harbor fish. If we can figure that out, we can determine which estuaries in the Northeast are the most essential in terms of providing valuable habitat for winter flounder and protect those places."
"This research is important in terms of environmental protection, trying to figure out which estuaries are producing the most number of fish for the population where people can actually fish for them, and trying to protect those estuaries so we don't harm the winter flounder," Bailey adds. "You wouldn't want to dredge an area if you know that's the prime area that produces fish for a Gulf of Maine winter flounder fishery."
For this study, researchers collected otoliths from juvenile winter flounder at 12 locations in estuaries and shallow coastal waters ranging from the Navesink River in New Jersey northward to New Hampshire's Great Bay. Lead author Bailey, currently a research assistant at the Marine Biological Lab in Woods Hole, Mass., ran the samples through a mass spectrometer to determine the chemical make-up of otoliths from each location.
Juvenile winter flounder from the three study sites in N.H., including Great Bay, Little Harbor and Hampton-Seabrook Harbor, were able to be traced back to their nurseries with reasonable (73%) accuracy and had slightly different otolith chemistries among sites, despite the relative proximity of the estuaries to one another, Bailey says. Looking at the data on a larger scale, the research results indicated regional groupings for winter flounder stocks from Cape Cod, the Gulf of Maine and New Jersey.
Fairchild and Kalnejais recently received a research grant from NOAA's Saltonstall-Kennedy Grant Program that will extend their work to adult winter flounder. Collecting adult otoliths will help them make a definitive connection between estuaries and offshore stocks.
"There's a lot of money riding on what winter flounder are doing," Fairchild says. "Fishermen would like to see the stocks rebound so they can harvest them again. The Wampanoag Tribe on Martha's Vineyard would like to see them make a comeback because of the cultural importance this species has played in their history. The Army Corps of Engineers cannot dredge navigable water channels during several months each year when winter flounder eggs may be present."
Funding for this project was provided by New Hampshire Sea Grant, the Leslie S. Hubbard Marine Program Endowment of UNH's School of Marine Science and Ocean Engineering, and the UNH Graduate School.
Photo credit: Xavier Fargas/iStock/Thinkstock.
Collisions with wind turbines kill about 100 golden eagles a year in some locations, but a new study that maps both potential wind-power sites and nesting patterns of the birds reveals sweet spots, where potential for wind power is greatest with a lower threat to nesting eagles.
Brad Fedy, a professor in the Faculty of Environment at the University of Waterloo, and Jason Tack, a PhD student at Colorado State University, took nesting data from a variety of areas across Wyoming, and created models using a suite of environmental variables and referenced them against areas with potential for wind development. The results of their research appear in PLOS ONE.
Increased mortalities threaten the future of long-lived species and, when a large bird like a golden eagle is killed by wind development, the turbine stops, causes temporary slowdowns and can result in fines to operators.
"We can't endanger animals and their habitats in making renewable energy projects happen," said Professor Fedy, a researcher in Waterloo's Department of Environment and Resource Studies. "Our work shows that it's possible to guide development of sustainable energy projects, while having the least impact on wildlife populations."
Golden eagles are large-ranging predators of conservation concern in the United States. With the right data, stakeholders can use the modelling techniques the researchers employed to reconcile other sustainable energy projects with ecological concerns.
"Golden eagles aren't the only species affected by these energy projects, but they grab people's imaginations," said Professor Fedy. "We hope that our research better informs collaboration between the renewable energy industry and land management agencies."
An estimated 75 to 110 golden eagles die at a wind-power generation operation in Altamont, California each year. This figure represents about one eagle for every 8 megawatts of energy produced.
Professor Fedy's map predictions cannot replace on-the-ground monitoring for potential risk of wind turbines on wildlife populations, though they provide industry and managers a useful framework to first assess potential development.
Contact: Pamela Smyth
University of Waterloo
MIT study finds phytoplankton are extremely sensitive to changing levels of desert dust.
A sandstorm over the Sahara desert in Africa seen by European Space Agency astronaut Alexander Gerst from the International Space Station.
Each spring, powerful dust storms in the deserts of Mongolia and northern China send thick clouds of particles into the atmosphere. Eastward winds sweep these particles as far as the Pacific, where dust ultimately settles in the open ocean. This desert dust contains, among other minerals, iron -- an essential nutrient for hundreds of species of phytoplankton that make up the ocean's food base.
Now scientists at MIT, Columbia University, and Florida State University have determined that once iron is deposited in the ocean, it has a very short residence time, spending only six months in surface waters before sinking into the deep ocean. This high turnover of iron signals that large seasonal changes in desert dust may have dramatic effects on surface phytoplankton that depend on iron.
"If there are changes to the sizes of deserts in Asia, or changes in the way people are using land, there could be a larger source of dust to the ocean," says Chris Hayes, a postdoc in MIT's Department of Earth, Atmospheric, and Planetary Sciences (EAPS). "It's difficult to predict how the whole ecosystem will change, but because the residence time [of iron] is very short, year-to-year changes in dust will definitely have an impact on phytoplankton."
The team's results are published in the journal Geochemica et Cosmochimica Acta. Co-authors include Ed Boyle, a professor of ocean geochemistry at MIT; David McGee, the Kerr-McGee Career Development Assistant Professor in EAPS; and former postdoc Jessica Fitzsimmons.
Dust to dust
Certain species of phytoplankton, such as cyanobacteria, require iron as a main nutrient to fuel nitrogen fixation and other growth-related processes. Hayes estimates that up to 40 percent of the ocean contains phytoplankton species whose growth is limited by the amount of iron available.
As desert dust is one of the only sources of oceanic iron, Hayes wanted to see to what extent changing levels of dust would have an effect on iron concentrations in seawater: Does iron stick around in surface waters for long periods, thereby making phytoplankton less sensitive to changes in incoming dust? Or does the mineral make a short appearance before sinking to inaccessible depths, making phytoplankton depend much more on seasonal dust?
To get answers, Hayes and his colleagues traveled to Hawaii to collect ocean samples at a station called ALOHA, the site of a long-term oceanography program conducted by the University of Hawaii. In September 2013, the team took a half-day cruise into open ocean, and then spent two weeks collecting samples of ocean water at varying depths.
The researchers acidified the samples and transported them back to the lab at MIT, where they analyzed the water for both iron and thorium -- a chemical element that is found in dust alongside iron. As it's difficult to determine the rate at which iron sinks from the ocean's surface to deep waters, Hayes reasoned that thorium might be a reasonable proxy.
Thorium has a number of isotopes: Thorium-232 is typically found in dust, and thorium-230 is produced from the decay of uranium, which decays to thorium at the same rate throughout the ocean. By comparing the amount of thorium-230 detected in ocean samples to the amount produced by uranium decay, Hayes was able to calculate thorium's removal rate, or the time it takes for the chemical to sink after settling on the ocean's surface.
This removal rate, he reasoned, is equivalent to the input rate of dust, or the rate at which dust is supplied to an ocean region. As the composition of an average desert dust particle is known, Hayes then extrapolated the input rate to estimate iron's residence time in surface waters.
A small piece of a big question
The team found that on average, iron tends to stay within 150 meters of the ocean's surface -- the layer in which phytoplankton resides ¬-- for about six months before accumulating on larger particles and sinking to the deep ocean. This residence time leaves a relatively short period for phytoplankton to absorb iron, making the organisms rather sensitive to any changes in incoming desert dust.
"Dust can change a lot from season to season -- by an order of magnitude," Hayes says. "From satellite images, you can see big pulses of dust coming from these deserts. That could change with climate change, and different precipitation patterns. So we're trying to keep track: If it does change, will it have an impact?"
As phytoplankton play a natural role in removing carbon dioxide from the atmosphere, better estimates of iron residence times, and desert dust inputs to the ocean, may help scientists gauge phytoplankton's role in combating climate change.
"It's a very small part that we're getting more quantitative about," Hayes says. "It's one piece that adds to trying to make the prediction: If there's more dust, will the ocean take up more carbon? That's a big-picture question that we can't totally answer with this, but we have one piece on the way to answering that."
Contact: Abby Abazorius
Massachusetts Institute of Technology
A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).
Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African plate slides underneath the Eurasian plate. About 10% of all tsunamis worldwide happen in the Mediterranean, with on average, one large tsunami happening in the region once a century. The risk to coastal areas is high because of the high population density in the area - some 130 million people live along the sea's coastline. Moreover, tsunami waves in the Mediterranean need to travel only a very short distance before hitting the coast, reaching it with little advance warning. The new study shows the extent of flooding in selected areas along the coasts of southern Italy and Greece, if hit by large tsunamis in the region, and could help local authorities identify vulnerable areas.
"The main gap in relevant knowledge in tsunami modelling is what happens when tsunami waves approach the nearshore and run inland," says Achilleas Samaras, the lead author of the study and a researcher at the University of Bologna in Italy. The nearshore is the zone where waves transform - becoming steeper and changing their propagation direction - as they propagate over shallow water close to the shore. "We wanted to find out how coastal areas would be affected by tsunamis in a region that is not only the most active in the Mediterranean in terms of seismicity and tectonic movements, but has also experienced numerous tsunami events in the past."
The team developed a computer model to represent how tsunamis in the Mediterranean could form, propagate and hit the coast, using information about the seafloor depth, shoreline and topography. "We simulate tsunami generation by introducing earthquake-generated displacements at either the sea bed or the surface," explains Samaras. "The model then simulates how these disturbances - the tsunami waves - propagate and are transformed as they reach the nearshore and inundate coastal areas."
As detailed in the Ocean Science study, the team applied their model to tsunamis generated by earthquakes of approximately M7.0 magnitude off the coasts of eastern Sicily and southern Crete. Results show that, in both cases, the tsunamis would inundate the low-lying coastal areas up to approximately 5 metres above sea level. The effects would be more severe for Crete where some 3.5 square kilometres of land would be under water.
"Due to the complexity of the studied phenomena, one should not arbitrarily extend the validity of the presented results by assuming that a tsunami with a magnitude at generation five times larger, for example, would result in an inundation area five times larger," cautions Samaras. "It is reasonable, however, to consider such results as indicative of how different areas in each region would be affected by larger events."
"Although the simulated earthquake-induced tsunamis are not small, there has been a recorded history of significantly larger events, in terms of earthquake magnitude and mainshock areas, taking place in the region," says Samaras. For example, a clustering of earthquakes, the largest with magnitude between 8.0 and 8.5, hit off the coast of Crete in 365 AD. The resulting tsunami destroyed ancient cities in Greece, Italy and Egypt, killing some 5000 people in Alexandria alone. More recently, an earthquake of magnitude of about 7.0 hit the Messina region in Italy in 1908, causing a tsunami that killed thousands, with observed waves locally exceeding 10 metres in height.
The team sees the results as a starting point for a more detailed assessment of coastal flooding risk and mitigation along the coasts of the Eastern Mediterranean. "Our simulations could be used to help public authorities and policy makers create a comprehensive database of tsunami scenarios in the Mediterranean, identify vulnerable coastal regions for each scenario, and properly plan their defence."
Contact: Barbara Ferreira
European Geosciences Union
UCSB researcher studying potential cumulative technological culture among New Caledonian crows finds strong evidence of social learning.
A New Caledonian crow in the wild uses a twig to dig for grubs. Credit: Jolyon Troscianko.
Among our greatest achievements as humans, some might say, is our cumulative technological culture -- the tool-using acumen that is passed from one generation to the next. As the implements we use on a daily basis are modified and refined over time, they seem to evolve right along with us.
A similar observation might be made regarding the New Caledonian crow, an extremely smart corvid and the only non-human species hypothesized to possess its own cumulative technological culture. How the birds transmit knowledge to each other is the focus of a study by Corina Logan, a junior research fellow at UC Santa Barbara's Sage Center for the Study of the Mind when she conducted her research. Currently, she is a Leverhulme Early Career Research Fellow in the Department of Zoology at the University of Cambridge.
"We don't know whether the crows have cumulative technological culture, and one of the reasons is that we don't know how they learn," said Logan. "There's a hypothesis that says in order for cumulative technological culture to occur you need to copy the actions of another individual. And we don't know whether the crows are paying attention to the actions of others when they learn from someone else."
But the crows have been observed using tools they've made out of long, narrow, palm-like Pandanus leaves. "It has a serrated edge, and they cut into one side of the leaf, then make another cut farther down and then rip off the part in between," Logan explained. "It makes a tool they can use to dig grubs out of logs."
Even more curious, according to Logan, the crows have been observed using tools made of the same material but in different shapes -- wide, narrow and stepped, which might be more structurally sound. However, no one has been able to explain the geographic variation in tool shapes -- all three shapes are seen at the south end of New Caledonia, while the stepped tool is more prevalent everywhere else.
"It's thought that in order for tool shapes to be transmitted, one bird would have to watch another cutting the leaf and then mimic that bird's actions," Logan continued. "That would require imitation or emulation."
A New Caldonian crow named Elsa fashions a tool from a twig. Credit: Russell Gray.
Evidence of Social Learning
So Logan devised a study to look at all the learning mechanisms -- social and asocial -- the crows employ when solving a foraging problem. To level the playing field so that those birds with more experience with one particular tool don't have an advantage over the others, Logan gave them a novel non-tool task.
She designed the experiment based on apparatus used by University of Leeds zoologist Will Hoppitt in a similar study he conducted on meerkats. "I used two apparatuses with multiple access points on each," she said, "so we could look at whether the crows were imitating or emulating, whether they were just paying attention to another crow's general location or whether they were paying attention to a specific area on an apparatus that another crow was interacting with."
Logan and colleagues found that the crows don't imitate or copy actions at all. "So there goes that theory," she said. "Assuming how they learn in a non-tool context carries over to a tool context, they wouldn't copy the actions of individuals they see cutting up Pandanus leaves to make tools."
But Logan and her team did strong evidence of social learning: If one crow sees a companion interacting with a particular area of the apparatus, reaching its bill through a door and pulling out a piece of boiled egg -- the treat -- the former is far more likely to try that particular door on either apparatus before choosing the other access options.
"It's called stimulus enhancement," she explained. "That's the social learning mechanism they're using. But there's another interesting aspect: Once they see another bird interact with the door, they go to that door and then begin to solve the problem on their own. And now they completely ignore social information and they just use trial and error learning to open the door and extract the food."
Even if one crow is at an apparatus and tries unsuccessfully to open the door, if he or she sees another crow on the second apparatus actually solving the problem correctly, the first crow doesn't use that information. "The social learning attracts them to a particular object and then they solve it through trial and error learning after that," Logan said.
"So we thought, 'Okay, if they don't imitate or emulate, how could they still have cumulative technological culture?'" she continued. Perhaps it's a combination of social learning and trial and error. Consider the grub digging. "In the wild, juveniles live with or near their parents for the first year or so," she explained. "The juveniles see their parents make and use a particular tool shape. And often the parent will leave the tool inside the hole in the log and the juveniles will grab it and start interacting with it."
Similar to the stimulus enhancement Logan and her team identified initially, the crow parents could draw their children's attention to the tools to make them more likely to interact with the tools. In addition, wild juveniles appear to learn how to use the tool through trial and error over the course of several months.
"We're suggesting it could be that they're copying the end result of another crow's action, but they're not copying the actual actions of the other crows," Logan continued. "It's actually a form of emulation but it doesn't involve the copying actions that were hypothesized previously."
Corina Logan, University of California - Santa Barbara. Credit: Sonia Fernandez.
Everyone's a Teacher
For this study, Logan placed the crows in small groups. One was a family that consisted of two parents and their two sons; another included two mated pairs that weren't related; and the third was made up of an adult and five juveniles. One of the juveniles was likely the adult's daughter but the rest were unrelated. It had been previously hypothesized that juveniles do most of the learning, with adults picking up very little, if anything, from the youngsters or from each other.
It turns out this was mistaken. "It didn't matter what group it was," Logan said. "Everyone learned from everyone -- juveniles from juveniles, adults from adults, juveniles from adults, adults from juveniles. It seems that if they have the opportunity, they'll learn from anyone. But because they live in family groups, it seems to constrain who they have the opportunity to learn from in the wild."
Logan plans to replicate the study with the great-tailed grackle, another highly intelligent bird. "They are expanding their range really rapidly," she said. "There are many questions about how they learn to forage so successfully in new environments. Are they learning from other species about what to forage on when they encounter a new food type? Or are they exploring on their own, using their own information?"
According to Logan, studies such as this broaden our understanding of the nature of cumulative technological culture. If it can spread through other mechanisms, such as stimulus enhancement -- simply drawing one's attention to something and imprinting on a particular way of doing things -- it could expand scientists' ideas about where they should look for cumulative culture in general, and cumulative technological culture in particular.
Contact: Andrea Estrada
University of California - Santa Barbara
Pope Francis. Credit: Aleteia Image Department.
A new national survey conducted by The Associated Press-NORC Center for Public Affairs Research and researchers at Yale University found that fewer than 1 in 3 Americans, and 40 percent of Catholics, are aware of Pope Francis's efforts to publicize global warming as a priority issue for the Catholic Church. While there is relatively low awareness of the papal encyclical, a majority of Americans say it is appropriate for the pope to take a public position on the issue of global warming. This is true even though very few Americans consider global warming as an issue of religion, social justice, or poverty. The nationwide poll was collected July 17 to 19, 2015, using the AmeriSpeak Omnibus, the probability-based panel of NORC at the University of Chicago. Online and telephone interviews using landlines and cell phones were conducted with 1,030 adults.
"This survey indicates that the Pope's message on global warming has not broken through to a majority of Catholics or Americans," said Trevor Tompson, director of The AP-NORC Center. "The survey found that few people consider the issue a religious or social justice one."
Some of the poll's key findings include:
"Even though the Pope's Encyclical is a major theological statement, fewer than 2 in 5 churchgoing Catholics heard about it from their priest in the month after it was released," said Anthony Leiserowitz, a faculty member of the Yale School of Forestry & Environmental Studies. "But this may change when Pope Francis visits the United States in September to bring his message personally."
This survey was conducted by The Associated Press-NORC Center for Public Affairs Research with input and funding from Yale University. Data were collected using AmeriSpeak®, which is a probability-based panel designed to be representative of the U.S. household population. Interviews for this survey were conducted July 17 to 19, 2015, with adults age 18 and over from the 50 states and the District of Columbia. Panel members were randomly drawn from AmeriSpeak®, and 1,030 completed the survey--894 via the web and 136 via telephone. The overall margin of sampling error is +/- 4.4 percentage points at the 95 percent confidence level, including the design effect. The margin of sampling error may be higher for subgroups.
Contact: Eric Young
NORC at the University of Chicago
Climate change is a 'people problem'.
Pope Francis recently made an impassioned plea for a "cultural revolution" to combat climate change, calling for collective action and "a conversation which includes everyone."
Thus far, the climate conversation has often neglected the contributions of one key group: social scientists. According to the new book Climate Change and Society: Sociological Perspectives
"Though more work always remains, the physical sciences have accomplished their core task when it comes to climate change," said Bill McKibben, a professor at Middlebury College and author of The End of Nature
Edited by environmental sociologists Robert J. Brulle, PhD, a professor in Drexel University's College of Arts and Sciences, and Riley E. Dunlap, a professor at Oklahoma State University, the book breaks new ground by presenting climate change as a thoroughly social phenomenon, embedded in behaviors, institutions and cultural practices.
"Climate change is a social problem," said Brulle. "If you want to deal with climate change, you have to deal with human behavior. We need to expand the conversation to include sociologists who can help address these human dimensions of climate change and answer questions like, how can we change our culture of consumption, how will we respond to extreme weather events caused by climate change and how do we bridge the political divide on this issue?"
This collection of essays summarizes existing approaches to understanding the social, economic, political and cultural dimensions of climate change. From the factors that drive carbon emissions to those that influence societal responses to climate change, the volume provides a comprehensive overview of the social dimensions of climate change.
The book is scheduled for release from Oxford University Press in September.
According to the authors, an improved understanding of the complex relationship between climate change and society is essential for modifying ecologically harmful human behaviors and institutional practices, creating just and effective environmental policies and developing a more sustainable future. "Climate Change and Society" provides a useful tool in efforts to integrate social science research, natural science research and policymaking regarding climate change and sustainability.
"Our goal is to create intellectual space for more critical perspectives on climate change, as current efforts have yielded little progress in dealing with this urgent problem," said Dunlap.
Produced by the American Sociological Association's Task Force on Sociology and Global Climate Change, this book presents a challenging shift from the standard climate change discourse and offers a valuable resource for students, scholars and professionals involved in climate change research and policy. All proceeds from the book will go to the American Sociological Association.
"With one hundred percent of the profits from this book going to the ASA, this project represents a voluntary effort by people who believe this issue merits this level of attention," said Brulle.
In addition to the editors, among the prominent contributors are Thomas Dietz, PhD, a professor of sociology and environmental science and policy and assistant vice president for environmental research at Michigan State University; Charles Perrow, PhD, professor emeritus of sociology at Yale University; J. Timmons Roberts, professor of sociology and environmental studies at Brown University; and Kathleen Tierney, PhD, director of the Natural Hazards Center, as well as a professor in the Department of Sociology and the Institute of Behavioral Science at the University of Colorado Boulder.
Brulle is a professor of sociology and environmental science at Drexel University, and Past Chair of the American Sociological Association's Section on Environment & Technology. He is author of Agency, Democracy and Nature: The U.S.Environmental Movement from a Crucial Theory Perspective
Dunlap is Dresser Professor and Regents Professor of Sociology at Oklahoma State University, past president of the International Sociological Association's Research Committee on Environment & Society and former chair of the American Sociological Association's Section on Environment & Technology. He is senior editor of the The International Handbook of Environmental Sociology (Elgar Original Reference)
Contact: Alex McKechnie
Drexel University
Nautilus pompilius (left) swimming next to a rare Allonautilus scrobiculatus (right) off of Ndrova Island in Papua New Guinea. Credit: Peter Ward.
In early August, biologist Peter Ward returned from the South Pacific with news that he encountered an old friend, one he hadn't seen in over three decades. The University of Washington professor had seen what he considers one of the world's rarest animals, a remote encounter that may become even more infrequent if illegal fishing practices continue.
The creature in question is Allonautilus scrobiculatus, a species of nautilus that Ward and a colleague had previously discovered off of Ndrova Island in Papua New Guinea. Nautiluses are small, distant cousins of squid and cuttlefish. They are an ancient lineage of animal, often christened a "living fossil" because their distinctive shells appear in the fossil record over an impressive 500 million year period. Ward says this recent sighting of Allonautilus indicates that there is still much to learn about these creatures.
"Before this, two humans had seen Allonautilus scrobiculatus," said Ward, who holds appointments at the UW in both the Department of Biology and the Department of Earth and Space Sciences. "My colleague Bruce Saunders from Bryn Mawr College found Allonautilus first, and I saw them a few weeks later."
Those sightings were in 1984, when Ronald Reagan was finishing his first term as president and the oldest millennials were starting preschool. Ward and Saunders collected several Allonautilus scrobiculatus specimens for analysis and realized that their gills, jaws, shell shape and male reproductive structures differ significantly from other nautilus species.
"Some features of the nautilus -- like the shell giving it the 'living fossil' label -- may not have changed for a long time, but other parts have," said Ward.
Allonautilus also sports a distinctive accessory clearly visible in photographs.
"It has this thick, hairy, slimy covering on its shell," said Ward. "When we first saw that, we were astounded."
This slimy nautilus turned out to be even more elusive than its siblings. Aside from another brief sighting by Saunders in 1986, Allonautilus disappeared until July 2015, when Ward returned to Papua New Guinea to survey nautilus populations. Since nautiluses are expert scavengers, Ward and his colleagues set up "bait on a stick" systems each evening -- fish and chicken meat suspended on a pole between 500 and 1,300 feet below the surface -- and filmed activity around the bait for 12 hours.
"We started using this approach in 2011," said Ward. "This year, there were about 30 guys involved and each day we would all watch the movies from the night before at 8X speed. There were a lot of 'ohs' and 'ahs'."
One night's footage from a site off of Ndrova Island showed an Allonautilus approach the bait after a 31-year absence from Ward's life. It was soon joined by another nautilus, and the two fought for access to the bait until a sunfish arrived on the scene.
"For the next two hours, the sunfish just kept whacking them with its tail," said Ward.
The team also used baited traps to capture several nautiluses, including Allonautilus, at a depth of about 600 feet. Since most nautiluses do not like the heat, the researchers brought them to the surface in chilled water to obtain small tissue, shell and mucous samples and measure the dimensions of each animal. They then transported the animals back to their capture site and released them.
Nautilus pompilius swimming above a rare Allonautilus scrobiculatus off the coast of Ndrova Island in Papua New Guinea. Credit: Peter Ward.
Ward and his colleagues used this information to determine the age and sex of each animal, as well as the diversity of each nautilus population in the South Pacific. Through these studies, they have learned that most nautilus populations are isolated from one another because they can only inhabit a narrow range of ocean depth.
"They swim just above the bottom of wherever they are," said Ward. "Just like submarines, they have 'fail depths' where they'll die if they go too deep, and surface waters are so warm that they usually can't go up there. Water about 2,600 feet deep is going to isolate them."
These restrictions on where nautiluses can go mean that populations near one island or coral reef can differ genetically or ecologically from those at another. The findings also pose a challenge for conservationists.
"Once they're gone from an area, they're gone for good," said Ward.
Illegal fishing and "mining" operations for nautilus shells have already decimated some populations, Ward said. This unchecked practice could threaten a lineage that has been around longer than the dinosaurs were and survived the two largest mass extinctions in Earth's history. In September, the U.S. Fish and Wildlife Service will decide whether to advocate for nautiluses to become a protected species under the Convention on International Trade in Endangered Species of Wildlife Fauna and Flora, or CITES treaty. Such protection could curb international trade in nautilus shells, with the aim of reducing nautilus harvests across the Pacific.
"As it stands now, nautilus mining could cause nautiluses to go extinct," said Ward.
Ward hopes to see Allonautilus again, especially since he would like to study how this species, which arose relatively recently according to genetic tests, behaves differently from other nautiluses. Its rarity makes this endeavor challenging.
"It's only near this tiny island," said Ward. "This could be the rarest animal in the world. We need to know if Allonautilus is anywhere else, and we won't know until we go out there and look."
Ward's main partners in this field season included Richard Hamilton and Manuai Matawai from the Nature Conservancy and Greg Barord from the City University of New York. More than 30 fisheries experts, guides and local residents in the Admiralty Islands and the Bismarck Archipelago of Papua New Guinea also provided crucial aid and support, Ward said. Their work is funded by National Geographic, the National Science Foundation's Division of Polar Programs and the Tiffany & Co. Foundation.
Contact: James Urton
University of Washington
A crown-of-thorns sea star eating a coral from the genus Acropora, which is a preferred meal for the organism. The photos were taken in the non-protected fishing area on Votua Reef, on the Coral Coast of the Fiji Islands. Credit: Cody Clements, Georgia Tech.
On the coral reef, knowing who's your friend and who's your enemy can sometimes be a little complicated.
Take seaweed, for instance. Normally it's the enemy of coral, secreting toxic chemicals, blocking the sunlight, and damaging coral with its rough surfaces. But when hordes of hungry crown-of-thorns sea stars invade the reef, everything changes, reports a study to be published August 25 in the journal Proceedings of the Royal Society B.
Seaweeds appear to protect coral from the marauding sea stars, giving new meaning to the proverb: "The enemy of my enemy is my friend." The findings demonstrate the complexity of interactions between species in ecosystems, and provide information that could be useful for managing endangered coral reefs.
"On the reefs that we study, seaweeds reduce coral growth by both chemical and mechanical means," said Mark Hay, a professor in the School of Biology at the Georgia Institute of Technology and the paper's senior author. "But we found that seaweeds can benefit corals by reducing predation by the crown-of-thorns sea stars. Corals surrounded by seaweeds were virtually immune to attack by the sea stars, essentially converting the seaweeds from enemies to friends."
The research was supported by the National Science Foundation, the National Institutes of Health and the Teasley endowment at Georgia Tech.
Crown-of-thorns sea stars (Acanthaster planci) are a major problem in the Pacific, where populations of the organisms rise and fall in cycles. On the Great Barrier Reef, for example, coral cover has declined by more than 50 percent over 25 years, and the voracious spine-covered creatures - which can travel as much as 80 meters per day - get much of the blame.
"You don't have to see the crown-of-thorns to know they have been on the reef," said Cody Clements, a Georgia Tech graduate student in Hay's lab and paper's first author. "You can see where they have been because they leave trails of bleached white coral. All they leave behind are the coral skeletons."
The sea stars climb onto favored corals, invert their stomachs out through their mouths, and digest away the corals' living tissues - leaving white skeletons like a trail of bread crumbs that allowed Clements to not only see where the creatures had been, but also to track them to hiding places in the rocks.
During a two-year study in a marine protected area off the coast of the Fiji Islands, Clements used both observations and field experiments to examine the role of sea stars and seaweeds in the health of coral.
Cages fabricated on the sea floor allow experimentation to understand the role of seaweeds in protecting corals from attack by crown-of-thorns sea stars. Credit: Cody Clements, Georgia Tech.
"Marine protected areas where we work are often surrounded by areas of coral reef that are degraded and have lots of seaweeds," said Clements. "If seaweed is increasing in prevalence in these degraded areas, it's likely that these predators will move into protected areas with more coral and less seaweed. That could compromise conservation efforts in these relatively small marine protected areas established to protect coral."
Clements first assessed the impact of seaweeds by comparing the growth of corals surrounded by varying levels of seaweed cover. To accurately measure growth, he established test colonies of the coral Montipora hispida attached to the necks of plastic soft drink bottles. Matching bottle caps were nailed into seabed rock, allowing colonies to be unscrewed from their anchorages to be accurately weighed, then returned. He placed varying amounts of the seaweed Sargassum polycystum adjacent to each test colony.
"The seaweed had a negative effect on the growth of the coral, and the more seaweed that was present, the greater the impact I observed," he said.
To study the relationship between sea star attacks and seaweed cover, Clements used photographs to assess the amount of sea star damage to different coral colonies outside the marine protected area, and related the damage to the amount of seaweed on corals in the attacked areas. Coral colonies that had been attacked had, on average, just eight percent seaweed coverage, while nearby colonies of the same species that had not been attacked averaged 55 percent coverage of seaweeds.
To more directly assess the protective role of the seaweed, Clements conducted an experiment. He fabricated ten cages in which he placed two Montipora coral colonies, one surrounded by varying levels of seaweed - between two and eight fronds - and the other lacking adjacent seaweeds. Into each cage he placed a sea star, then observed how much of each coral would be eaten.
"At the highest densities of seaweed, the sea stars were completely deterred," Clements said. "They wouldn't eat the coral surrounded by the seaweeds." Coral surrounded by lower densities of seaweed were sometimes eaten, while the corals without seaweed protection were always consumed by the sea stars.
Researchers aren't sure if the protective effects of the seaweed are mechanical or chemical - or perhaps both. But when Clements repeated the experiment with plastic aquarium seaweed instead of real seaweed, he found that it also had protective effects, suggesting the seaweed may be simply physical impediments making the coral difficult for the sea stars to find or consume.
Finally, Clements examined sea star feeding when the predator was given a choice between an unprotected coral it doesn't normally consume (Porites cylindra) and Montipora - a favored prey - that had been surrounded by Sargussum. The sea stars didn't eat the Montipora, and would wait as long as ten days before finally consuming the Porites.
Researcher Cody Clements places bottle caps into the rocky sea floor off Votua Reef, on the Coral Coast of the Fiji Islands. The caps are used to anchor small colonies of coral for experimentation to understand how crown-of-thorns sea stars and seaweed affect coral growth. The bottle caps allow for the coral colonies to be removed for accurate weighing. Credit: Cody Clements, Georgia Tech.
"If you've got a choice between ice cream and broccoli, you're going to choose ice cream - unless broccoli is the only thing you can get," he said.
The varying relationship between coral and seaweed illustrates the kind of complexity scientists have to understand when studying species-diverse ecosystems such as coral reefs, Clements noted.
"In a scenario that didn't involve the crown-of-thorns sea stars, interactions with the seaweed would have been negative for the coral," he noted. "But when you add the crown-of-thorns into the equation, it can be beneficial for the coral to be associated with the seaweed. Even if it suffers reduced growth, that's better than being eaten."
Information from research like this can help scientists protect corals, which are essential to the survival of reef ecosystems.
"We are interested not only in how direct interactions between species play out, but also how these indirect interactions come into the picture and influence the wider community," said Clements. "When it comes to coral reefs, that is very important because these interactions can affect the trajectory of an entire community of organisms."
This research was supported by the National Science Foundation, by the Fogarty International Center of the National Institutes of Health and U19TW007401, and by the Teasley Endowment to Georgia Tech.
