"DEEP TIME" FUTURE PREDICTIONS

Time spiral: looking back through time to understand future climate change.  Credit: NASA

FROM:  NATIONAL SCIENCE FOUNDATION 
Back to the future: Scientists look into Earth's "Deep Time" to predict future effects of climate change

Climate change alters the way in which species interact with one another--a reality that applies not just to today or to the future, but also to the past, according to a paper published by a team of researchers in this week's issue of the journal Science.

"We found that, at all time scales, climate change can alter biotic interactions in very complex ways," said paleoecologist Jessica Blois of the University of California, Merced, the paper's lead author.

"If we don't incorporate this information when we're anticipating future changes, we're missing a big piece of the puzzle."

Blois asked for input from researchers who study "deep time," or the very distant past, as well as those who study the present, to help make predictions about what the future holds for life on Earth as climate shifts.

Co-authors of the paper are Phoebe Zarnetske of Yale University, Matthew Fitzpatrick of the University of Maryland, and Seth Finnegan of the University of California, Berkeley.

"Climate change and other human influences are altering Earth's living systems in big ways, such as changes in growing seasons and the spread of invasive species," said Alan Tessier, program director in the National Science Foundation's (NSF) Division of Environmental Biology, which co-funded the research with NSF's Division of Earth Sciences.

"This paper highlights the value of using information about past episodes of rapid change from Earth's history to help predict future changes to our planet's ecosystems."

Scientists are seeing responses in many species, Blois said, including plants that have never been found in certain climates--such as palms in Sweden--and animals like pikas moving to higher elevations as their habitats grow too warm.

"The worry is that the rate of current and future climate change is more than species can handle," Blois said.

The researchers are studying how species interactions may change between predators and prey, and between plants and pollinators, and how to translate data from the past and present into future models.

"One of the most compelling current questions science can ask is how ecosystems will respond to climate change," said Lisa Boush, program director in NSF's Division of Earth Sciences.

"These researchers address this using the fossil record and its rich history," said Boush. "They show that climate change has altered biological interactions in the past, driving extinction, evolution and the distribution of species.

"Their study allows us to better understand how modern-day climate change might influence the future of biological systems and the rate at which that change will occur."

While more research is needed, Blois said, changes can be observed today as well as in the past, although it's harder to gather information from incomplete fossil records.

Looking back, there were big changes at the end of major climate change periods, such as the end of the last Ice Age when large herbivores went extinct.

Without those mega-eaters to keep certain plants at bay, new communities of flora developed, most of which in turn are now gone.

"People used to think climate was the major driver of all these changes," Blois said, "but it's not just climate. It's also extinction of the megafauna, changes in the frequency of natural fires, and expansion of human populations. They're all linked."

People are comfortable with the way things have been, said Blois. "We've known where to plant crops, for example, and where to find water."

Now we need to know how to respond, she said, to changes that are already happening--and to those coming in the near future.

-NSF-

DEEPWATER HORIZON OIL SHEEN SOURCE IDENTIFIED

Oil Sheen.  Credit:  NOAA

FROM: NATIONAL SCIENCE FOUNDATION

Study Identifies Source of Oil Sheens Near Deepwater Horizon Site

A chemical analysis indicates that the source of oil sheens recently found floating at the ocean's surface near the site of the Gulf of Mexico Deepwater Horizon oil spill is pockets of oil trapped within the wreckage of the sunken rig.


First reported to the U.S. Coast Guard by multinational oil and gas company BP in September 2012, the oil sheens raised public concern that the Macondo well, which was capped in July 2010, might be leaking.

However, both the Macondo well and the natural oil seeps common to the Gulf of Mexico were confidently ruled out, according to researchers from the University of California Santa Barbara (UCSB) and the Woods Hole Oceanographic Institution (WHOI).

The results are published this week in the journal Environmental Science & Technology.

"Silver linings in the dark cloud of the Deepwater Horizon spill are very hard to come by," says Don Rice, program director in the National Science Foundation's (NSF) Division of Ocean Sciences, which funded the research.

"Among the precious few are the lessons we've learned about the marine biogeochemistry of petroleum mixtures. This team has demonstrated convincingly that we can also use what we have learned for forensic purposes."

The researchers used a recently patented method to fingerprint the chemical makeup of the oil sheens, and to estimate the location of the source based on the extent to which gasoline-like compounds evaporated from the sheens.

"The results demonstrate a recently developed geochemical analytical method and may have real-world implications in environmental management strategies for future contamination incidents," says Deborah Aruguete, program director in NSF's Division of Earth Sciences, which co-funded the research.

Because every oil sample contains chemical clues pointing to the reservoir it came from, scientists can compare it to other samples to determine if they share a common source.

"This appears to be a slow leak from the wreckage of the rig, not another catastrophic discharge from a deep oil reservoir," says geochemist David Valentine of UCSB.

"Continued oil discharge to the Gulf of Mexico from the wreckage of the Deepwater Horizon rig is not a good thing, but there is some comfort that the amount of leakage is limited to the pockets of oil trapped within the wreckage of the rig."

Valentine and WHOI's Chris Reddy have worked on Deepwater Horizon for much of the last three years, investigating a wide range of problems, including the composition of the oil, detection of subsurface plumes, the biodegradation of the oil, the fate of the dispersants and the chemical transition from floating oil slicks to sunken tar balls.

"Because of our ongoing funding from NSF, we were prepared to interrogate the source of mysterious oil sheens in the Gulf of Mexico," said Valentine.

"We've been exploring new ways to do this for several years in the context of natural seeps, and this event provided us an opportunity to apply our fundamental advances to a real-world problem."

The scientists analyzed 14 sheen samples skimmed from the sea surface during two trips to the Gulf of Mexico.

Using comprehensive two-dimensional gas chromatography, a technique developed in Reddy's lab, the researchers first confirmed that the sheens contained oil from the Macondo well.

But the sheen samples also contained trace amounts of olefins, industrial chemicals used in drilling operations. The presence of olefins provided a fingerprint for the sheens the scientists could compare to the samples they had analyzed during the last three years.

Olefins are not found in crude oil and their uniform distribution in the sheens indicated that the Macondo well was unlikely to be the source.

The team surmised that the sheens must be coming from equipment exposed to olefins during drilling operations.

"The occurrence of these man-made olefins in all our sheen samples points to a single main source, which contains both Macondo oil and lesser amounts of the drilling fluids that harbor the olefins," said Valentine.

"This pointed us to the wreckage of the rig, which was known to have both, as the most likely source for the sheens."

The researchers compared the sheen samples to other field samples, some of which they expected would contain olefins and some they thought would not.

The reference samples included two pieces of debris from the Deepwater Horizon found floating in May 2010, as well as oil collected by BP in October 2012, during an inspection of the 80-ton cofferdam that had been abandoned at the seafloor after its use in a failed attempt to cover the Macondo well in 2010.

The team's gas chromatography analysis of BP's cofferdam samples definitively showed that it was not the sole source of the leak as there were no olefins present.

Prior to the analysis the cofferdam had become the prime suspect as the source when BP found small amounts of oil leaking from its top.

BP scientists acquired oil samples from this leak point before sealing the leak, thinking they had resolved the problem. However, the sheens on the sea surface persisted, and the lack of olefins pointed to another source entirely.

When Valentine and Reddy compared the chemical makeup of the sheens with debris found floating in 2010, they found a match. That debris, which came from the rig itself, was coated with oil and was contaminated by drilling mud olefins.

"The ability to fingerprint synthetic hydrocarbons allowed us to crack this case," Valentine said. "We were able to exclude a number of suspects and match the olefin fingerprint in the new oil slicks to that of the wreckage from the sunken rig."

The chemical analysis also told researchers which sheens had surfaced more recently than others, allowing them to reconstruct a trajectory for local ocean currents that pointed back to the oil's source.

By looking for sheens that showed the least amount of evaporation, they determined that oil surfaced closer to Deepwater Horizon wreckage than to the cofferdam site.

To explain how the oil might be trapped and released from the wreckage, the scientists point out that when the Deepwater Horizon rig sank, it was holding tanks containing hundreds of barrels of a mixture of drilling mud and oil.

Over time, corrosive seawater can create small holes through which oil can slowly escape to the surface. The researchers suspect that the containers on the rig holding trapped oil may be the source of the recent oil sheen.

In addition to Valentine and Reddy, the research team consisted of Christoph Aeppli and Robert Nelson of WHOI, and Matthias Kellermann of UCSB.

The Gulf of Mexico Research Initiative, Woods Hole Oceanographic Institution and a Swiss National Science Foundation Postdoctoral Fellowship also funded the research.

-NSF-

NSF DISCUSSES THE FUTURE OF THE WHITEBARK PINE

Whitebark Pine.  Credit:  U.S. Forest Service/ Wikimedia. 

FROM: NATIONAL SCIENCE FOUNDATION

Whitebark Pine Trees: Is Their Future at Risk?
There's trouble ahead for the whitebark pine, a mountain tree that's integral to wildlife and water resources in the western United States and Canada.


Over the last decade, some populations of whitebark pines have declined by more than 90 percent. But these declines may be just the beginning.

New research results, supported by the National Science Foundation (NSF) and published today in the Journal of Ecology, suggest that as pine stands are increasingly fragmented by widespread tree death, surviving trees may be hindered in their ability to produce their usually abundant seeds.

"With fewer seeds, you get less regeneration," says ecologist Joshua Rapp, affiliated with NSF's Harvard Forest Long-Term Ecological Research (LTER) site and lead author of the paper.

Whitebark pine populations vary between producing a high number of seed cones some years, and a low number of seed cones other years.

This variation depends on four factors: male pollen cones, female seed cones, wind and proximity.

Each year, pollen from male cones is carried on the air to fertilize female seed cones perched atop nearby trees.

"In low-cone years, less pollen is released, reaching extremely few female cones," says Elizabeth Crone, senior ecologist at the NSF Harvard Forest LTER site and co-author of the paper.

"But as more and more whitebark pines die, every year becomes a low-cone year."

In isolated pockets of trees, the gene pool is also diminished, meaning the seeds produced may be less viable over time.

"For decades, researchers have struggled to understand why many different organisms--trees, fish, corals, insects--from various habitats reproduce synchronously and at certain intervals," says Saran Twombly, program director in NSF's Division of Environmental Biology, which funded the research.

"By combining field data on seed and pollen production for whitebark pines with models that simulate mature cone production, this study helps to answer that question for these pines."

To reach their conclusions, the scientists had to look back in time.

They inspected branches from seven whitebark pine sites in western Montana, counting the scars left by pollen cones and seed cones.

"All the years with a high number of seed cones had one thing in common: a high number of pollen cones," says Rapp. "The success of the seeds seems to depend on the amount of pollen produced."

Whitebark pine seeds are an essential food source for many animals in mountain habitats.

The Clark's Nutcracker, a mountain bird, can store up to 100,000 seeds in underground caches each year. Squirrels also store thousands of seeds underground.

A diminished number of seed cones has an effect on grizzly bears, the scientists say; the bears regularly raid squirrel seed caches to prepare for winter hibernation.

"In the past, low years for whitebark pine cones have led to six times more conflicts between grizzlies and humans, as hungry bears look for food in campgrounds," says Crone.

"Now, concerns about viability of whitebark pine populations are one of the main reasons grizzly bears in Yellowstone National Park are still listed as threatened under the Endangered Species Act."

Birds, squirrels and bears are not the only species that depend on whitebark pine.

Vast stands of whitebark pine help to maintain the mountain snowpacks that provide water to more than 30 million people in 16 U.S. states each year.

Whitebark pines are often the only trees at the highest elevations. Their branches retain snow as it blows across gusty mountaintops. Their shade moderates snow-melt in the spring, keeping flows down the mountain in check.

A small percentage of whitebark pine trees have outlived the ongoing destruction by pests and disease. These trees are the next area of focus for Crone's team.

"We want to find out whether the surviving trees are still producing cones," Crone says. "They represent the future of whitebark pines."

-NSF-

UNDERSTANDING NATURES BIODIVERSITY: ECOLOGY AND EVOLUTIONARY BIOLOGY

Marbled Salamander.  Credit:  NSF/Wikimedia Commons

FROM: NATIONAL SCIENCE FOUNDATION

Understanding Biodiversity Patterns in Nature: It Takes Two Fields--Ecology and Evolutionary Biology
What do marbled and spotted salamanders in ponds in eastern North America have to teach us about biodiversity patterns elsewhere on Earth?

Plenty, if research conducted by biologist Mark Urban of the University of Connecticut is any guide.

In a paper published today in the journal Proceedings of the Royal Society B, Urban reports results that may fundamentally change how scientists view the importance of evolution in ecological research.

"This project looked closely at the separate and interactive contributions of genetic and environmental factors in shaping pond food webs," says Alan Tessier, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research.

"The results add to a growing understanding of the importance of genetic variation within species, and of eco-evolutionary processes in explaining patterns of biodiversity."

The findings show that the evolutionary divergence of populations is as important as biodiversity patterns based on ecological features, such as the presence of a top predator.

In this study, the subjects were the marbled salamander, an apex, or, top predator, in temporary ponds; the spotted salamander; and their shared zooplankton prey.

The marbled salamander breeds in the autumn. Its larvae grow under the ice of ephemeral ponds during winter.

As a result, marbled salamander larvae eat zooplankton all winter--and grow large enough to eat the spotted salamander larvae that hatch in these same ponds in late spring.

But Urban discovered that spotted salamanders sharing space with marbled salamanders have evolved so that they're born with voracious appetites.

Their increased foraging makes sense, he says, given that these salamanders live in ponds largely depleted of zooplankton prey, due to the presence of marbled salamanders.

The smaller salamanders need to grow quickly to reach a size at which marbled salamanders can't easily capture them.

"The evidence suggests that the repeated evolution of high foraging rates in spotted salamanders is an adaptive response to marbled salamander predation," says Urban.

Knowing how apex predators such as marbled salamanders structure biological communities, he says, requires that scientists understand their direct ecological effects as predators, and their indirect effects via the natural selection they impose.

"Finding that adaptive evolution may disguise strong ecological effects means that a range of ecological predictions are likely to be unreliable if we ignore how evolution affects biological communities."

Urban refers to this as "the invisible finger of evolution" which, he says, may tip the scales toward or away from ecological influences.

"That the effect of an apex predator can be so strong that it causes evolutionary responses in other species," he says, "shows that ecology and evolution are inexorably intertwined."

-NSF-

NSF UNVEILS LOOK AT DAM DAMAGE TO RIVER IN CHINA

 

The Salween Delta from space (south is to the upper left). From NSF-Wikimedia Commons.

FROM: NATIONAL SCIENCE FOUNDATION
Small Dams on Chinese River Harm Environment More Than Expected
A fresh look at the environmental impacts of dams on an ecologically diverse and partially protected river in China found that small dams can pose a greater threat to ecosystems and natural landscapes than large dams.

Large dams have been considered more harmful than their smaller counterparts.

But researchers' surveys of habitat loss and damage at several dam sites on the Nu River and its tributaries in Yunnan Province revealed that the environmental effects of small dams are often greater--sometimes by several orders of magnitude--than of large dams.

"Small dams have hidden detrimental effects, particularly when effects accumulate" through multiple dam sites, said Kelly Kibler, a water resources engineer who led the study while at Oregon State University.

"That's one of the main outcomes, to demonstrate that the perceived absence of negative effects from small hydropower is not always correct."

She and Desiree Tullos, also a water resources engineer at Oregon State, report their findings in a paper accepted for publication in Water Resources Research, a journal of the American Geophysical Union (AGU).

"These researchers have taken advantage of what is essentially a natural experiment that allowed them to compare the effects of hydroelectric dams of different sizes," said Tom Baerwald of the National Science Foundation's (NSF) Directorate for Social, Behavioral & Economic Sciences, which co-funded the research with other NSF directorates. "The results are applicable beyond this region."

To compare the effects of small and large dams, Kibler investigated 31 small dams built on tributaries to China's Nu River and four large dams proposed for the main stem of the Nu River.

She assessed the environmental effects of these dams in 14 categories--including the area and quality of habitat lost, the length of river channel affected, the amount of conservation land affected, and the landslide risk.

Because information regarding large dams is restricted under the Chinese State Secrets Act, Kibler modeled the potential effects of the four large dams using publicly-available information from hydropower companies, development agencies, and academic literature.

After evaluating data from the field, hydrologic models, and Environmental Impact Assessment reports on the small dams, Kibler and Tullos concluded that effects of the small dams exceeded those of large dams on nine out of the 14 characteristics they studied.

One particularly detrimental effect of the small dams is that they often divert the flow of the river to hydropower stations, leaving several kilometers of river bed dewatered, Kibler said.

From its headwaters in the Tibetan Plateau, the Nu River flows through China, Myanmar (Burma) and Thailand.

"While the number of small hydropower dams in operation or planned for tributaries to the Nu River is unreported," the authors state in their paper, "our field surveys indicate that nearly one hundred small dams currently exist within Nujiang Prefecture alone."

Thirteen large hydropower dams are proposed for the mainstem of the Nu River in Tibet and Yunnan Province in China.

Environmental, social, and economic factors make the Nu River basin extremely sensitive to hydropower installations.

In addition to supporting several protected species, the region is home to a large proportion of ethnic minorities and valuable natural resources, the authors report.

While large hydropower projects are managed by the central government, and both large and small hydropower projects undergo environmental impact assessments, decisions about small hydropower projects are made at a provincial or other regional level and often receive less oversight, Kibler and Tullos state.

The lack of regulation paired with a dearth of communication between small dam projects in China allows for the effects to multiply and accumulate through several dam sites, the authors write.

To mitigate the detrimental effects of small dams, there's a need for comprehensive planning for low-impact energy development, said Kibler and Tullos.

"The lack of analyses of the cumulative effects of small hydropower," Kibler said, "is a significant research gap with important policy implications."

-NSF-

THE PATTERNS NATURE OF PLANET EARTH AND LIFE

Photo:  Huricane Irene.  Credit:  NASA
FROM: NATIONAL SCIENCE FOUNDATION
Tale of Two Scientific Fields--Ecology and Phylogenetics--Offers New Views of Earth's Biodiversity
Patterns in nature are in everything from ocean currents to a flower's petal.
Scientists are taking a new look at Earth patterns, studying the biodiversity of yard plants in the U.S. and that of desert mammals in Israel, studying where flowers and bees live on the Tibetan plateau and how willow trees in America's Midwest make use of water.
They're finding that ecology, the study of relationships between living organisms and their environment, and phylogenetics, research on evolutionary relationships among groups of organisms, are inextricably intertwined.
Results of this tale of two fields are highlighted in a special, August 2012 issue of the journal Ecology, published by the Ecological Society of America (ESA). Most of the results reported are funded by the National Science Foundation (NSF).
The issue will be released at the annual ESA meeting, held this year from August 5-10 in Portland, Ore.
Melding information from ecology and phylogenetics allows scientists to understand why plants and animals are distributed in certain patterns across landscapes, how these species adapt to changing environments across evolutionary time--and where their populations may be faltering.
"To understand the here and now, ecologists need more knowledge of the past," says Saran Twombly, program director in NSF's Division of Environmental Biology. "Incorporating evolutionary history and phylogenies into studies of community ecology is revealing complex feedbacks between ecological and evolutionary processes."
Maureen Kearney, also a program director in NSF's Division of Environmental Biology adds, "Recent studies have demonstrated that species' evolutionary histories can have profound effects on the contemporary structure and composition of ecological communities."
In the face of rapid changes in Earth's biota, understanding the evolutionary processes that drive patterns of species diversity and coexistence in ecosystems has never been more pressing, write co-editors Jeannine Cavender-Bares of the University of Minnesota, David Ackerly of the University of California at Berkeley and Kenneth Kozak of the University of Minnesota.
"As human domination of our planet accelerates," says Cavender-Bares, "our best hope for restoring and sustaining the ‘environmental services' of the biological world is to understand how organisms assemble, persist and coexist in ecosystems across the globe."
Papers in the volume address subjects such as the vanishingly rare oak savanna ecosystem of U.S. northern tier states, revealing an ancient footprint of history on the savanna as well as how it has fared in a 40-year fire experiment.
Other results cover the influence of ecological and evolutionary factors on hummingbird populations; habitat specialization in willow tree communities; growth strategies in tropical tree lineages and their implications for biodiversity in the Amazon region; and the characteristics of common urban plants.
"The studies in this issue show that knowledge of how organisms evolve reveals new insights into the ecology and persistence of species," says Cavender-Bares.
Plants in urban yards, for example, are more closely related to each other--and live shorter lives--than do plants in rural areas, found Cavender-Bares and colleagues.
Their study compared plant diversity in private urban yards in the U.S. Midwest with that in the rural NSF Cedar Creek Long-Term Ecological Research site in Minnesota.
Cities are growing faster and faster, with unexpected effects, says Sonja Knapp of the Hemholtz Center for Environmental Research in Germany, lead author of the paper reporting the results.
"Understanding how urban gardening affects biodiversity is increasingly important," says Cavender-Bares. "Urbanites should consider maintaining yards with a higher number of species."
In the special issue, researchers also look at topics such as what determines the number of coexisting species in local and regional communities of salamanders. Kenneth Kozak of the University of Minnesota and John Wiens of Stony Brook University report that variation in the amount of time salamanders occupy different climate zones is the primary factor.
Evolution of an herbaceous flower called goldfields, and how that led to the plant's affinity for certain habitats, is the subject of a paper by David Ackerly, Nancy Emery of Purdue University and colleagues. Emery is the paper's lead author.