RESEARCHERS SAY OCEAN WARMING WILL LEAD TO MARINE ANIMAL MIGRATION

FROM:  NATIONAL SCIENCE FOUNDATION
Warmer, lower-oxygen oceans will shift marine habitats

Changes will result in marine animals moving away from equator
Modern mountain climbers usually carry tanks of oxygen to help them reach the summit. The combination of physical exertion and lack of oxygen at high altitudes creates a major challenge for mountaineers.

Now, just in time for World Oceans Day on Monday, June 8, researchers have found that the same principle applies to marine species during climate change.

Warmer water temperatures will speed up the animals' metabolic need for oxygen, as also happens during exercise, but the warmer water will hold less of the oxygen needed to fuel their bodies, similar to what happens at high altitudes.

Results of the study are published in this week's issue of the journal Science.

"This work is important because it links metabolic constraints to changes in marine temperatures and oxygen supply," said Irwin Forseth, program director in the National Science Foundation's (NSF) Division of Integrative Organismal Systems, which funded the research along with NSF's Division of Ocean Sciences.

"Understanding connections such as this is essential to allow us to predict the effects of environmental changes on the distribution and diversity of marine life.”

Marine animals pushed away from equator

The scientists found that these changes will act to push marine animals away from the equator. About two thirds of the respiratory stress due to climate change is caused by warmer temperatures, while the rest is because warmer water holds less dissolved gases such as oxygen.

"If your metabolism goes up, you need more food and you need more oxygen," said lead paper author Curtis Deutsch of the University of Washington.

"Aquatic animals could become oxygen-starved in a warmer future, even if oxygen doesn't change. We know that oxygen levels in the ocean are going down now and will decrease more with climate warming."

Four Atlantic Ocean species studied

The study centered on four Atlantic Ocean species whose temperature and oxygen requirements are well known from lab tests: Atlantic cod in the open ocean; Atlantic rock crab in coastal waters; sharp snout seabream in the sub-tropical Atlantic; and common eelpout, a bottom-dwelling fish in shallow waters in high northern latitudes.

Deutsch and colleagues used climate models to see how projected temperature and oxygen levels by 2100 would affect the four species ability to meet their future energy needs.

The near-surface ocean is projected to warm by several degrees Celsius by the end of this century. Seawater at that temperature would hold 5-10 percent less oxygen than it does now.

Results show that future rock crab habitat, for example, would be restricted to shallower water, hugging the more oxygenated surface.

Equatorial part of animals' ranges uninhabitable

For all four species, the equatorial part of their ranges would become uninhabitable because peak oxygen demand would be greater than the supply.

Viable habitats would shift away from the equator, displacing from 14 percent to 26 percent of the current ranges.

The authors believe the results are relevant for all marine species that rely on aquatic oxygen as an energy source.

"The Atlantic Ocean is relatively well-oxygenated," Deutsch said. "If there's oxygen restriction in the Atlantic Ocean marine habitat, then it should be everywhere."

Climate models predict that the northern Pacific Ocean's relatively low oxygen levels will decline even more, making it the most vulnerable part of the seas to habitat loss.

"For aquatic animals that are breathing water, warming temperatures create a problem of limited oxygen supply versus higher demand," said co-author Raymond Huey, a University of Washington biologist who has studied metabolism in land animals and in human mountain climbers.

"This simple metabolic index seems to correlate with the current distributions of marine organisms," he said. "That means that it gives us the power to predict how range limits are going to shift with warming."

A day-to-day "dead zone"

Previously, marine scientists thought about oxygen more in terms of extreme events that could cause regional die-offs of marine animals, also known as dead zones.

"We found that oxygen is also a day-to-day restriction on where species will live," Deutsch said.

"The effect we're describing will be part of what's pushing species around in the future."

Other co-authors are Hans Otto-Portner of the Alfred Wegener Institute in Germany; Aaron Ferrel of the University of California, Los Angeles; and Brad Seibel at the University of Rhode Island.

The Gordon and Betty Moore Foundation and the Alfred Wegener Institute also funded the research.

-NSF-
Media Contacts
Cheryl Dybas, NSF

NASA SCIENCECASTS: NO TURNING BACK-WEST ANTARCTIC GLACIERS IN IRREVERSIBLE DECLINE

GLOBAL WARMING ACCELERATES DEOUGHT-INDUCED FOREST DEATH

WHERE IS THE GINSENG GOING? ANOTHER CHANGE IN THE NORTH AMERICAN FOREST

American Ginseng.  USFWS

FROM: NATIOAL SCIENCE FOUNDATION
The Stress of Being Ginseng
Being surrounded by ginseng--a low-growing green-leafed herb of North American forests--may have been common in 1751, but today? Ginseng is under siege.

Biologist James McGraw of West Virginia University should know. On World Environment Day, and indeed every day, McGraw says that we can learn much about the environment around us from one small plant.

Funded by a National Science Foundation (NSF) Long Term Research in Environmental Biology (LTREB) grant, McGraw and colleagues peer into the lives of more than 4,000 individual ginseng plants each year to see how they're faring.

"These understory plants are subject to all manner of [environmental] stresses," says McGraw. "After a while, you begin to wonder why there are any left."

Facing a panoply of threats

First, he says, there's harvesting for medicinal uses, "which is widespread and often illegally or at least unethically done. Then we have our four-footed friends--white-tailed deer--which eat a significant number of plants every year."

The plants' next challenge is the growth of invasive species such as multiflora rose and garlic mustard, which compete with ginseng.

The effects of global warming, including summers with heat waves and droughts, add to the burden for these plants of cooler climes. "Ginseng is also affected by ice storms, late frosts and hurricane flooding," says McGraw.

Then these Indiana Joneses of the plant world must survive what McGraw refers to as "natural pests:" insects defoliators and fungal pathogens.

Last--but definitely not least--is us.

"We're just beginning to understand what humans are doing to the forests where ginseng thrives: timbering, suppressing natural fires, mining, clearing land for housing developments, the list goes on and on," says McGraw.

The persistence of a slow-growing and valuable medicinal plant "despite all this," he says, "is a testament to the resilience of nature--and to the stewardship of those land-owners who care about protecting biodiversity in their forests."

Species in an extinction vortex

Tigers, elephants and ginseng all share a common feature, says Saran Twombly, director of NSF's LTREB program.

"These dwindling populations face increasing threats that trap them in an extinction vortex," Twombly says.

"McGraw's research relies on long-term data to identify the factors threatening populations of this important forest plant. The results show the knife-edge that separates healthy and unhealthy populations."

The NSF LTREB award "has been critical to our understanding of the 'big picture' of ginseng conservation," says McGraw.

He and colleagues work on one species of ginseng, Panax quinquefolius L., American ginseng.This member of the ginseng family, whose genus name Panax means "all heal" in Greek, hides deep in eastern deciduous woodlands.

The plant was historically found in rich, cool hardwood forests--from southern Quebec and Ontario south to northern Georgia, and west as far as Minnesota, eastern Oklahoma and northern Louisiana.

"Ginseng populations vary from frequent to uncommon to rare across the landscape," says McGraw, "but they're almost always small, usually fewer than 300 plants."

Medicinal plant for the ages

The species has long been valued for its medicinal qualities, especially by Asian cultures. They've integrated American ginseng into traditional medicinal practices as a complement to native Asian ginseng species.

In Asia, ginseng is considered an adaptogen--it enhances overall energy levels.

"In western medicine, ginseng has exhibited anti-cancer properties in cell cultures," says McGraw. "It's also shown beneficial effects on blood sugar and obesity, as well as on enhancing the immune system for prevention of colds and flu."

After ginseng was discovered in North America, the market quickly became profitable enough to fuel intense wild harvesting, eventually reaching an industrial scale.

"Ginseng shares a part of early American history," says McGraw. "Its roots--the most sought-after parts--were first exported to Asia from the United States in the early 1700s."

In one typical year (1841), more than 290,000 kilograms of dry ginseng roots were shipped from North America to the Asian continent.

"Although average root size was larger in the 1800s than it is today," says McGraw, "even a conservative estimate suggests that this represents at least 64 million roots."

Ginseng at the forefront

Harvest of the plant has continued apace, he says, particularly in the Appalachian region, where the sale of ginseng still supplements household incomes.

Ecologists began studying ginseng because of its value as a wild-harvested species, and its decrease in abundance after decades of harvesting.

Now, however, ginseng has become an important model species--a sensitive indicator of the effects of global and regional environmental change on deciduous forests.

"The prominence of American ginseng has led to its use as a 'phytometer' [a gauge] to better understand how change is affecting lesser-known plant species in eastern North America," says McGraw.

The data in his project come from 30 ginseng populations in seven states. "Our study populations are in habitats from suburban woodlots to rich, old-growth forests," McGraw says.

In a paper published this year in the Annals of The New York Academy of Sciences, McGraw and co-authors state that the Asian market has made ginseng North America's most important harvested wild medicinal plant over the past two centuries.

That status prompted a listing on CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) Appendix II. All species on Appendix II are susceptible to extinction in the absence of trade controls.

Most states with ginseng populations are converging on a uniform start date for harvesting--Sept. 1. "That allows time after harvest for planting ripe seeds that will lead to recovery of the plants," McGraw says.

Since forests are, for the most part, open to everyone, ginseng will continue to be harvested as long as there is immediate profit to be made, scientists believe.

Successful sustainability in such open access habitats, they say, depends on management of the resource by those who actively harvest it.

Sustainability and ginseng

McGraw and colleagues' research shows that ginseng harvesters willing to employ a stewardship strategy gain the most benefit by harvesting when seeds are ripe, usually in autumn months, then planting the seeds to ensure high germination rates.

September is a summertime away. But in northeastern forests, ginseng leaves have already unfurled.

"Now they face a gamut of environmental challenges," says McGraw. "They're rooted in place, left with whatever nature--or more likely humans--dish out. If we want ginseng to be part of the future landscape, we had best tread very carefully."

"Ginseng is not everywhere common," wrote Swedish naturalist Peter Kalm in 1749. "Sometimes you may search the woods for several miles without finding a single plant. Round Montreal they formerly grew in abundance, but there is not a single plant to be found, so they have been rooted out."

By three centuries later, northeastern forests may be empty--at least of an unassuming and "all healing" herb named ginseng.

GLOBAL WARMING AND RAINFALL

 

Model simulations spanning 140 years show that warming from carbon dioxide will change the frequency that regions around the planet receive no rain (brown), moderate rain (tan), and very heavy rain (blue). The occurrence of no rain and heavy rain will increase, while moderate rainfall will decrease. Credit: NASA's Goddard Space Flight Center Scientific Visualization Studio

FROM: NASA

NASA Study Projects Warming-Driven Changes in Global Rainfall

WASHINGTON -- A NASA-led modeling study provides new evidence that global warming may increase the risk for extreme rainfall and drought.

The study shows for the first time how rising carbon dioxide concentrations could affect the entire range of rainfall types on Earth.

Analysis of computer simulations from 14 climate models indicates wet regions of the world, such as the equatorial Pacific Ocean and Asian monsoon regions, will see increases in heavy precipitation because of warming resulting from projected increases in carbon dioxide levels. Arid land areas outside the tropics and many regions with moderate rainfall could become drier.

The analysis provides a new assessment of global warming's impacts on precipitation patterns around the world. The study was accepted for publication in the American Geophysical Union journal Geophysical Research Letters.

"In response to carbon dioxide-induced warming, the global water cycle undergoes a gigantic competition for moisture resulting in a global pattern of increased heavy rain, decreased moderate rain, and prolonged droughts in certain regions," said William Lau of NASA's Goddard Space Flight Center in Greenbelt, Md., and lead author of the study.

The models project for every 1 degree Fahrenheit of carbon dioxide-induced warming, heavy rainfall will increase globally by 3.9 percent and light rain will increase globally by 1 percent. However, total global rainfall is not projected to change much because moderate rainfall will decrease globally by 1.4 percent.

Heavy rainfall is defined as months that receive an average of more than about 0.35 of an inch per day. Light rain is defined as months that receive an average of less than 0.01 of an inch per day. Moderate rainfall is defined as months that receive an average of between about 0.04 to 0.09 of an inch per day.

Areas projected to see the most significant increase in heavy rainfall are in the tropical zones around the equator, particularly in the Pacific Ocean and Asian monsoon regions.

Some regions outside the tropics may have no rainfall at all. The models also projected for every degree Fahrenheit of warming, the length of periods with no rain will increase globally by 2.6 percent. In the Northern Hemisphere, areas most likely to be affected include the deserts and arid regions of the southwest United States, Mexico, North Africa, the Middle East, Pakistan, and northwestern China. In the Southern Hemisphere, drought becomes more likely in South Africa, northwestern Australia, coastal Central America and northeastern Brazil.

"Large changes in moderate rainfall, as well as prolonged no-rain events, can have the most impact on society because they occur in regions where most people live," Lau said. "Ironically, the regions of heavier rainfall, except for the Asian monsoon, may have the smallest societal impact because they usually occur over the ocean."

Lau and colleagues based their analysis on the outputs of 14 climate models in simulations of 140-year periods. The simulations began with carbon dioxide concentrations at about 280 parts per million -- similar to pre-industrial levels and well below the current level of almost 400 parts per million -- and then increased by 1 percent per year. The rate of increase is consistent with a "business as usual" trajectory of the greenhouse gas as described by the United Nations' Intergovernmental Panel on Climate Change.

Analyzing the model results, Lau and his co-authors calculated statistics on the rainfall responses for a 27-year control period at the beginning of the simulation, and also for 27-year periods around the time of doubling and tripling of carbon dioxide concentrations.
They conclude the model predictions of how much rain will fall at any one location as the climate warms are not very reliable.

"But if we look at the entire spectrum of rainfall types we see all the models agree in a very fundamental way -- projecting more heavy rain, less moderate rain events, and prolonged droughts," Lau said.

NASA : STUDY FINDS ANCIENT WARMING GREENED ANTARCTICA

Photo:  Antarctic Sea Ice.  Credit:  NASA
FROM: NASA 
WASHINGTON -- A new university-led study with NASA participation finds ancient Antarctica was much warmer and wetter than previously 
suspected. The climate was suitable to support substantial vegetation
-- including stunted trees -- along the edges of the frozen
continent.

The team of scientists involved in the study, published online June 17
in Nature Geoscience, was led by Sarah J. Feakins of the University of Southern California in Los Angeles, and included researchers from 
NASA's Jet Propulsion Laboratory in Pasadena, Calif., and Louisiana
State University in Baton Rouge.

By examining plant leaf wax remnants in sediment core samples taken
from beneath the Ross Ice Shelf, the research team found summer
temperatures along the Antarctic coast 15 to 20 million years ago
were 20 degrees Fahrenheit (11 degrees Celsius) warmer than today,
with temperatures reaching as high as 45 degrees Fahrenheit (7
degrees Celsius). Precipitation levels also were found to be several
times higher than today.

"The ultimate goal of the study was to better understand what the
future of climate change may look like," said Feakins, an assistant
professor of Earth sciences at the USC Dornsife College of Letters,
Arts and Sciences. "Just as history has a lot to teach us about the
future, so does past climate. This record shows us how much warmer
and wetter it can get around the Antarctic ice sheet as the climate
system heats up. This is some of the first evidence of just how much
warmer it was."

Scientists began to suspect that high-latitude temperatures during the
middle Miocene epoch were warmer than previously believed when
co-author Sophie Warny, assistant professor at LSU, discovered large
quantities of pollen and algae in sediment cores taken around
Antarctica. Fossils of plant life in Antarctica are difficult to come
by because the movement of the massive ice sheets covering the
landmass grinds and scrapes away the evidence.

"Marine sediment cores are ideal to look for clues of past vegetation,
as the fossils deposited are protected from ice sheet advances, but
these are technically very difficult to acquire in the Antarctic and
require international collaboration," said Warny.

Tipped off by the tiny pollen samples, Feakins opted to look at the
remnants of leaf wax taken from sediment cores for clues. Leaf wax
acts as a record of climate change by documenting the hydrogen
isotope ratios of the water the plant took up while it was alive.

"Ice cores can only go back about one million years," Feakins said.
"Sediment cores allow us to go into 'deep time.'"

Based upon a model originally developed to analyze hydrogen isotope
ratios in atmospheric water vapor data from NASA's Aura spacecraft,
co-author and JPL scientist Jung-Eun Lee created experiments to find
out just how much warmer and wetter climate may have been.

"When the planet heats up, the biggest changes are seen toward the
poles," Lee said. "The southward movement of rain bands associated
with a warmer climate in the high-latitude southern hemisphere made
the margins of Antarctica less like a polar desert, and more like
present-day Iceland."

The peak of this Antarctic greening occurred during the middle Miocene
period, between 16.4 and 15.7 million years ago. This was well after
the age of the dinosaurs, which became extinct 64 million years ago.
During the Miocene epoch, mostly modern-looking animals roamed Earth,
such as three-toed horses, deer, camel and various species of apes.
Modern humans did not appear until 200,000 years ago.

Warm conditions during the middle Miocene are thought to be associated
with carbon dioxide levels of around 400 to 600 parts per million
(ppm). In 2012, carbon dioxide levels have climbed to 393 ppm, the
highest they've been in the past several million years. At the
current rate of increase, atmospheric carbon dioxide levels are on
track to reach middle Miocene levels by the end of this century.

High carbon dioxide levels during the middle Miocene epoch have been
documented in other studies through multiple lines of evidence,
including the number of microscopic pores on the surface of plant
leaves and geochemical evidence from soils and marine organisms.
While none of these 'proxies' is as reliable as the bubbles of gas
trapped in ice cores, they are the best evidence available this far
back in time. While scientists do not yet know precisely why carbon
dioxide was at these levels during the middle Miocene, high carbon
dioxide, together with the global warmth documented from many parts
of the world and now also from the Antarctic region, appear to
coincide during this period in Earth's history.

This research was funded by the U.S. National Science Foundation with
additional support from NASA. The California Institute of Technology
in Pasadena manages JPL for NASA.

HUMMINGBIRD FOOD SUPPLY WITHERS AWAY

Photo Credit:  U.S. Fish And Wildlife Service.
FROM:  NATIONAL SCIENCE FOUNDATION
Where Have All the Hummingbirds Gone?
May 30, 2012
The glacier lily as it's called, is a tall, willowy plant that graces mountain meadows throughout western North America. It flowers early in spring, when the first bumblebees and hummingbirds appear.

Or did.
The lily, a plant that grows best on subalpine slopes, is fast becoming a hothouse flower. In Earth's warming temperatures, its first blooms appear some 17 days earlier than they did in the 1970s, scientists David Inouye and Amy McKinney of the University of Maryland and colleagues have found.

The problem, say the biologists, with the earlier timing of these first blooms is that the glacier lily is no longer synchronized with the arrival of broad-tailed hummingbirds, which depend on glacier lilies for nectar.

By the time the hummingbirds fly in, many of the flowers have withered away, their nectar-laden blooms going with them.

Broad-tailed hummingbirds migrate north from Central America every spring to high-mountain breeding sites in the western United States. The birds have only a short mountain summer to raise their young. Male hummingbirds scout for territories before the first flowers bloom.

But the time between the first hummingbird and the first bloom has collapsed by 13 days over the past four decades, say Inouye and McKinney. "In some years," says McKinney, "the lilies have already bloomed by the time the first hummingbird lands."

The biologists calculate that if current trends continue, in two decades the hummingbirds will miss the first flowers entirely.

The results are reported in a paper in the current issue of the journal Ecology. In addition to McKinney and Inouye, co-authors of the paper are Paul CaraDonna of the University of Arizona; Billy Barr of the Rocky Mountain Biological Laboratory in Crested Butte, Colo.; David Bertelsen of the University of Arizona; and Nickolas Waser, affiliated with all three institutions.

"Northern species, such as the broad-tailed hummingbird, are most at risk of arriving at their breeding sites after their key food resources are no longer available, yet ecologists predict that species will move northward as climate warms," says Saran Twombly, program director in the National Science Foundation's Division of Environmental Biology, which funded the research.

"These conflicting pressures challenge society to ensure that species don't soon find themselves without a suitable place to live."

Broad-tailed hummingbirds that breed farther south have fewer challenges.
"In Arizona, for example," says Inouye, "there's no obvious narrowing of the timing between the first arriving males and the first blooms of, in this case, the nectar-containing Indian paintbrush."

Higher latitudes may be more likely to get out of sync ecologically because global warming is happening fastest there.

As the snow continues to melt earlier in the spring, bringing earlier flowering, says Inouye, the mountains may come alive with glacier lilies long before hummingbirds can complete their journey north.
"Where have all the flowers gone?" then will be "where have all the hummingbirds gone?"

A WARMING CLIMATE AND RAINFALL CHANGES

Photo: South Africa,  Senecio Serpens (Groundcover).   Credit:  Wikimedia.

FROM:  NATIONAL SCIENCE FOUNDATION

Warming climate may mean less rainfall for drought-sensitive regions of the Southern Hemisphere, according to results just published by an international research team.

Geoscientist Curt Stager of Paul Smith's College in Paul Smiths, N.Y., and colleagues found that rainfall in South Africa during the last 1,400 years was affected by temperature--with more rain falling during cool periods and less during warm ones.

The findings, published in the journal Climate of the Past, are supported by the National Science Foundation (NSF).

"The link between climate change and rainfall in certain latitudes can have large effects on ecosystems," said Paul Filmer, program officer in NSF's Directorate for Geosciences. 

"Plants, for example, may be able to grow in a wider area, or conversely, be squeezed up a mountain or onto a peninsula. When the affected ecosystem supports a food crop, that can mean a bonanza--or a famine."

Theoretical climate models have shown that global warming could push storm tracks southward "and away from the mainlands of southern Africa, South America and Australia," said Stager.

"This research supports those predictions of increasing aridity, which could lead to major problems for societies and ecosystems in these already-arid places."

A poleward shift in winds could also affect the flow of marine currents around the tip of Africa, changing air and water temperatures farther afield, including in the Atlantic and Indian Oceans.

Stager, lead author of the paper, collected sediment samples from Lake Verlorenvlei in South Africa. By analyzing the diatoms--tiny, glassy-shelled algae--preserved in sediment cores from the bottom of the lake, he and other researchers were able to reconstruct rainfall patterns dating back to 600 A.D.

Two Paul Smith's College undergraduate students, Christiaan King and Jay White, also participated in the study, along with scientists from the University of Maine and from institutions in South Africa and Europe.

Rainfall at the southernmost tip of Africa is governed by a sinuous belt of eastward winds that migrate like a meandering river, depending on the season.

In summer months, these winds drift closer to Antarctica, carrying rain clouds over the ocean; in winter, the winds move over the African continent.

The shifting winds bring rains that provide much of the annual water supply.

"A poleward retreat of these winds would have serious consequences for cities like Cape Town, for farms and wineries, and for local animal and plant communities," Stager said.

"The same also appears to be true for the semi-arid winter rainfall regions of South America and Australia-New Zealand."

Michael Meadows, a scientist at the University of Cape Town who co-authored the paper, said that hundreds of species of rare flowering plants native to the area's fynbos ecosystem are threatened by the changes.

"These plants are tough, and are already used to dry conditions," Meadows said. "But more aridity could make fires more frequent, which could damage the soils and make it even harder for the plants to survive.

"Unfortunately, this is their only native habitat, so such a change might threaten their existence."

According to Stager, such links to mobile storm tracks make these regions exceptionally vulnerable to the effects of greenhouse gas build-up.

"When it comes to climate change, there's more to consider than warming alone," he said. "In places like these, increasing drought could bring far-reaching challenges."

A GLOBAL WARMING OASIS IS DISCOVERED

FROM:  NATIONAL SCIENCE FOUNDATION
Coral reefs near the island nation of Kiribati may be somewhat protected from global warming. Credit: NOAA
Global Warming Refuge Discovered Near At-Risk
Pacific Island Nation of Kiribati
Scientists predict ocean temperatures will rise in the equatorial Pacific by the end of the century, wreaking havoc on coral reef ecosystems.

But a new study shows that climate change could cause ocean currents to operate in a way that mitigates warming near a handful of islands right on the equator.
Those islands include some of the 33 coral atolls that form the nation of Kiribati. This low-lying country is at risk from sea-level rise caused by global warming.
Surprisingly, these Pacific islands within two degrees north and south of the equator may become isolated climate change refuges for corals and fish.

"The finding that there may be refuges in the tropics where local circulation features buffer the trend of rising sea surface temperature has important implications for the survival of coral reef systems," said David Garrison, program director in the National Science Foundation's (NSF) Division of Ocean Sciences, which funded the research.
Here's how it could happen, according to the study by Woods Hole Oceanographic Institution (WHOI) scientists Kristopher Karnauskas and Anne Cohen, published today in the journalNature Climate Change.

At the equator, trade winds push a surface current from east to west.
About 100 to 200 meters below, a swift countercurrent develops, flowing in the opposite direction.

This, the Equatorial Undercurrent (EUC), is cooler and rich in nutrients. When it hits an island, like a rock in a river, water is deflected upward on an island's western flank.
This upwelling process brings cooler water and nutrients to the sunlit surface, creating localized areas where tiny marine plants and corals flourish.
On color-enhanced satellite maps showing measurements of global ocean chlorophyll levels, these productive patches of ocean stand out as bright green or red spots--for example, around the Galapagos Islands in the Eastern Pacific.
But as you gaze west, chlorophyll levels fade like a comet tail, giving scientists little reason to look closely at scattered low-lying coral atolls in that direction.
These islands are easy to overlook because they are tiny, remote, and lie at the far left edge of standard global satellite maps that place continents in the center.
Karnauskas, a climate scientist, was working with coral scientist Cohen to explore how climate change would affect central equatorial Pacific reefs.

When he changed the map view on his screen in order to view the entire tropical Pacific at once, he saw that chlorophyll concentrations jumped up again exactly at the Gilbert Islands on the equator.

Satellite maps also showed cooler sea surface temperatures on the west sides of these islands, part of Kiribati.

"I've been studying the tropical Pacific Ocean for most of my career, and I had never noticed that," he said. "It jumped out at me immediately, and I thought, 'there's probably a story there.'"

So Karnauskas and Cohen began to investigate how the EUC would affect the equatorial islands' reef ecosystems, starting with global climate models that simulate effects in a warming world.

Global-scale climate models predict that ocean temperatures will rise nearly 3 degrees Celsius (5.4 degrees Fahrenheit) in the central tropical Pacific.
Warmer waters often cause corals to bleach, a process in which they lose the tiny symbiotic algae that live in them and provide vital nutrition.
Bleaching has been a major cause of coral mortality and loss of coral reef area during the last 30 years.

Even the best global models, with their planet-scale views and lower resolution, cannot predict conditions in areas as small as these small islands, Karnauskas said.
So the scientists combined global models with a fine-scale regional model to focus on much smaller areas around minuscule islands scattered along the equator.
To accommodate the trillions of calculations needed for such small-area resolution, they used the new high-performance computer cluster at WHOI called "Scylla."
"Global models predict significant temperature increases in the central tropical Pacific over the next few decades, but in truth conditions can be highly variable across and around a coral reef island," Cohen said.

"To predict what the coral reef will experience in global climate change, we have to use high-resolution models, not global models."

The model predicts that as air temperatures rise and equatorial trade winds weaken, the Pacific surface current will also weaken by 15 percent by the end of the century.
The then-weaker surface current will impose less friction and drag on the EUC, so this deeper current will strengthen by 14 percent.

"Our model suggests that the amount of upwelling will actually increase by about 50 percent around these islands and reduce the rate of warming waters around them by about 0.7 C (1.25 F) per century," Karnauskas said.

A handful of coral atolls on the equator, some as small as 4 square kilometers (1.54 square miles) in area, may not seem like much.

But Karnauskas' and Cohen's results say that waters on the western sides of the islands will warm more slowly than at islands 2 degrees, or 138 miles, north and south of the equator that are not in the path of the EUC.

That gives the Gilbert Islands a significant advantage over neighboring reef systems.
"While the mitigating effect of a strengthened Equatorial Undercurrent will not spare corals the perhaps-inevitable warming expected for this region, the warming rate will be slower around these equatorial islands," Karnauskas said.

"This may allow corals and their symbiotic algae a better chance to adapt and survive."
If the model holds true, even if neighboring reefs are hard-hit, equatorial island coral reefs may survive to produce larvae of corals and other reef species.

Like a seed bank for the future, they might be a source of new corals and other species that could re-colonize damaged reefs.

"The globe is warming, but there are things going on underfoot that will slow that warming for certain parts of certain coral reef islands," said Cohen.
"These little islands in the middle of the ocean can counteract global trends and have a big effect on their own future," Karnauskas said, "which I think is a beautiful concept."

SCIENTISTS SAY GLOBAL WARMING AFFECTS AREAS OF SNOWFALL THE MOST

FROM:  NATIONAL SCIENCE FOUNDATION
Scientists at the H.J. Andrews LTER site, one of 26 such NSF sites, study water resources.
Long-Term Ecological Research Reveals Causes and Consequences of Environmental Change
Photo Credit: NSF H.J. Andrews LTER Site

April 6, 2012
As global temperatures rise, the most threatened ecosystems are those that depend on a season of snow and ice, scientists from the National Science Foundation (NSF) Long Term Ecological Research (LTER) Network have found.
"The vulnerability of cool, wet areas to climate change is striking," says scientist Julia Jones of Oregon State University and the H.J. Andrews LTER site in Oregon.
Jones is the lead author of a paper in the April issue of the journal BioScience; the issue features results from more than 30 years of long-term ecological research.
In semi-arid regions like the Southwestern United States, mountain snowpacks are the dominant source of water for human consumption and irrigation.
Research by Jones and colleagues shows that as average temperatures increase in these snowy ecosystems, a significant amount of stream water is lost to the atmosphere.
The study involves more than thirty years of data from 19 forested watersheds across the country. All the study sites provide water to major agricultural areas and to medium and large cities.

But, like many long-term studies, this one revealed a surprise.
Water flow only decreased in the research sites with winter snow and ice.
"Streams in dry forested ecosystems seem more resilient to warming," says Jones. "These ecosystems conserve more water as the climate warms, keeping streamflow within expected bounds."

A range of factors can affect watersheds, from human influence past and present, to El Niño climate oscillations.

"Long-term records are finally long enough to begin to separate the effects of each," Jones says.

"This research shows both the vulnerability and resilience of headwater streams. Such nuanced insights are crucial to effective management of public water supplies."
Surprising and transformative results are common in the NSF LTER network, which comprises 26 sites in North America, Puerto Rico, the island of Moorea and Antarctica.
The network has amassed more than 30 years of data on environmental recovery and change.

In contrast to most such research, which spans only a few years, LTER studies are sustained over decades, documenting gradual changes and long-term variability that often cannot be revealed by short-term studies.

"Each additional year of LTER data helps us to better understand how ecosystems respond to environmental change," says Scott Collins, an ecologist at the University of New Mexico and principal investigator at the Sevilleta LTER site in New Mexico.
"Such understanding provides valuable information for federal agencies, land managers and legislators who want to develop responsible policies to deal with a rapidly changing world."

The results reveal that the LTER network's diversity of long-term research approaches--including detailed observations and experiments, environmental gradient studies and complex simulation models--can contribute to new solutions in an era of unprecedented environmental change.

"How can we evaluate the ability of natural ecosystems to sustain critical ecological processes and the human societies that depend on them?" asks Saran Twombly, NSF LTER program director.

"LTER research demonstrates the unique and powerful insights that emerge from long-term studies and the analysis of long-term data," she says. "The results reach beyond scientists to engage the public and decision-makers."

In addition to deciphering ecosystem-level clues, LTER research can identify the biological winners and losers in a changing climate.

"The cryosphere, or the part of the Earth affected by snow and ice, has been shrinking," says scientist Andrew Fountain of Portland State University in Oregon and the McMurdo Dry Valleys LTER site.

"Populations of microbes, plants and animals that depend on snow and ice will decrease if they are unable to migrate. But life that finds the cryosphere too hostile should expand."
In shallower snow, he explains, animals such as white-tailed deer, mule deer, elk and caribou expend less energy and can more easily escape predators.
"One species' loss can be another species' gain," says Fountain.
The retrospective look at the LTER network comes at a time when institutions charged with stewarding the nation's environmental health are increasingly being challenged to provide a basis for their decision-making.

An article by scientist Charles Driscoll of New York's Syracuse University and the Hubbard Brook LTER site in New Hampshire shows that LTER research has contributed to important decisions over the past decade, including state and regional forest and watershed management policies.

"LTER datasets and experiments help inform local- to national-scale decisions on climate change, pollution, fire, land conversion and other pressing environmental challenges," says Driscoll. "This creates a crucial bridge between the scientific community and society."
Demand for natural resources is increasing with the global human population, which the United Nations projects will reach at least nine billion by 2050.
Long-term ecosystem data can help researchers simulate a region's future based on a range of possible human actions.

"For example, how might forest ecosystems change if more people begin to use wood to heat their homes?" asks Jonathan Thompson of the Smithsonian Conservation Biology Institute in Front Royal, Va., and the Harvard Forest LTER site in Massachusetts. Thompson is the lead author of a paper in the volume.

Each year, some 2,000 scientists and students carry out more than 200 large-scale LTER field experiments to find new answers.

The resulting datasets are freely and publicly available online.
"LTER sites are providing transformative information about the causes and consequences of climate and environmental changes to ecosystems," says David Garrison, NSF program director for coastal and ocean LTER sites.

"They are some of our best hopes for providing the sound scientific underpinnings needed to guide policy for the challenges of future environmental change."