Oceanic Defense: climate change

Showing posts with label climate change. Show all posts

3.23.2011

Conservationists Develop Coral 'Stress Test' to Identify Reefs More Likely to Survive Climate Change

ScienceDaily — Researchers from the Wildlife Conservation Society have developed a "stress test" for coral reefs as a means of identifying and prioritizing areas that are most likely to survive bleaching events and other climate change factors. The researchers say that these "reefs of hope" are priorities for national and international management and conservation action.

The test is a model that looks at environmental factors that stress corals -- mainly from rising sea temperatures -- and how these stresses affect overall coral and fish diversity. The results will help conservationists and managers identify reef systems most likely to survive over the next 50 years.

The study appears in the online edition of Global Change Biology. The authors include Tim R. McClanahan, Joseph M. Maina, and Nyawira A. Muthiga of the Wildlife Conservation Society.
The model uses layers of historical data, satellite imagery, and field observations to produce a composite map on the status of reefs in the western Indian Ocean, in addition to an index of coral communities, their diversity, and their susceptibility to bleaching.

The study encompasses a wide swath of the western Indian Ocean, ranging from the Maldives to South Africa, an area already heavily impacted by bleaching events and coral mortality.

The model identified the coastal regions stretching from southern Kenya to northern Mozambique, northeastern Madagascar, the Mascarene Islands, and the coastal border of Mozambique and South Africa as having the most promising characteristics of high diversity and low environmental stress.

The authors say these biologically diverse and hardy reefs are therefore a priority for implementing management that will reduce human impacts and stresses, while alternative strategies for adaptation are necessary in areas with lower chances of long-term survival.
"The future is going to be more stressful for marine ecosystems, and coral and their dependent species top the list of animals that are going to feel the heat of climate warming," said Dr. McClanahan, the study's lead author and WCS Senior Conservationist. "The study provides us with hope and a map to identify conservation and management priorities where it is possible to buy some time for these important ecosystems until the carbon emissions problems have been solved."

The coral reefs of the western Indian Ocean represent a significant portion of the overall biodiversity of tropical reef systems worldwide.

The western Indian Ocean also represents a crucial testing ground for management responses to climate-driven events such as coral bleaching. For instance, an estimated 45 percent of living coral was killed during 1998's warm temperature anomaly.

Caleb McClennen, Director of the Wildlife Conservation Society's Marine Program, said: "Reducing human impacts to minimize the multiple stressors on these globally important reefs will give corals a fighting chance in the age of global climate change. These results reveal a window of opportunity for the future conservation of the ocean's most biodiverse ecosystem."

From Fiji to Glover's Reef, The John D. and Catherine T. MacArthur Foundation and The Tiffany & Co. Foundation have provided critical support for Dr. McClanahan's research, which examines the climate change effects, ecology, fisheries, and management of coral reefs at key sites throughout the world.

Source: http://www.sciencedaily.com/releases/2011/03/110322151302.htm

About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

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3.15.2011

Shifting spring: Arctic plankton blooming up to 50 days earlier now

Climate researchers have long warned that the Arctic is particularly vulnerable to global warming. The dramatic shrinking of sea ice in areas circling the North Pole highlights those concerns.

A new report finds that the disappearing ice has apparently triggered another dramatic event - one that could disrupt the entire ecosystem of fish, shellfish, birds and marine mammals that thrive in the harsh northern climate.

Each summer, an explosion of tiny ocean-dwelling plants and algae, called phytoplankton, anchors the Arctic food web.

But these vital annual blooms of phytoplankton are now peaking up to 50 days earlier than they did 14 years ago, satellite data show.

"The ice is retreating earlier in the Arctic, and the phytoplankton blooms are also starting earlier," said study leader Mati Kahru, an oceanographer at the Scripps Institution of Oceanography in San Diego.

Drawing on observations from three American and European climate satellites, Kahru and his international team studied worldwide phytoplankton blooms from 1997 through 2009. The satellites can spot the blooms by their color, as billions of the tiny organisms turn huge swaths of the ocean green for a week or two.

The blooms peaked earlier and earlier in 11 percent of the areas where Kahru's team was able to collect good data. Kahru said the impacted zones cover roughly 1 million square kilometers, including portions of the Foxe Basin and the Baffin Sea, which belong to Canada, and the Kara Sea north of Russia.

In the late 1990s, phytoplankton blooms in these areas hit their peak in September, only after a summer's worth of relative warmth had melted the edges of the polar ice cap. But by 2009 the blooms' peaks had shifted to early July.

"The trend is obvious and significant, and in my mind there is no doubt it is related to the retreat of the ice," said Kahru, who published the work in the journal Global Change Biology.
"A 50-day shift is a big shift," said plankton researcher Michael Behrenfeld of Oregon State University, who was not involved in the study. "As the planet warms, the threat is that these changes seen closer to land may spread across the entire Arctic."

Ecologists worry that the early blooms could unravel the region's ecosystem and "lead to crashes of the food web," said William Sydeman, who studies ocean ecology as president of the nonprofit Farallon Institute in Petaluma, Calif.

When phytoplankton explode in population during the blooms, tiny animals called zooplankton - which include krill and other small crustaceans - likewise expand in number as they harvest the phytoplankton. Fish, shellfish and whales feed on the zooplankton, seabirds snatch the fish and shellfish, and polar bears and seals subsist on those species.

The timing of this sequential harvest is programmed into the reproductive cycles of many animals, Sydeman said. "It's all about when food is available." So the disrupted phytoplankton blooms could "have cascading effects up the food web all the way to marine mammals."
But the Arctic food web is poorly studied, and so any resulting decline in fish, seabirds and mammals will be difficult to spot.

As the Arctic Ocean north becomes less and less icy, commercial fisherman have begun eyeing these vast, untapped waters as an adjunct to the famously rich fishing grounds of the subarctic Bering Sea, west of Alaska.

But in 2009, the U.S. body overseeing fishing in the region, the North Pacific Fishery Management Council, banned commercial fishing in the Arctic Ocean, citing a lack of knowledge about how many - or even what kind - of fish live there.

"There are no catches authorized because we don't know enough about the fish populations there to set a quota," said Julie Speegle, a spokeswoman for the Alaska office of the National Marine Fisheries Service.

Last week, that service reported results from the first fish survey in 30 years of the Beaufort Sea, an arm of the Arctic Ocean north of Alaska. The survey found sizeable populations of several commercially valuable species, including pollock, Pacific cod and snow crab.

How these populations will respond to the ever-earlier plankton blooms is a big unknown, Sydeman said. But other research has shown that northern Atlantic cod populations crash when plankton blooms in that region shift in time.

Last week, the National Snow and Ice Data Center, in Boulder, Colo., reported that in February, Arctic sea ice covered a smaller area than ever seen in that month, tying with February 2005 as the most ice-free February since satellites began tracking Arctic ice in 1979.

The annual average Arctic sea ice coverage has decreased about 12 percent since then, a trend that appears to be accelerating, said Walt Meier, a research scientist at the center. Summer ice coverage has declined even more dramatically, he said, with the Arctic losing almost a third of its late-summer ice over the past 30 years.

Source: http://www.washingtonpost.com/wp-dyn/content/article/2011/03/06/AR2011030603417.html

By Brian Vastag
Washington Post Staff Writer
Monday, March 7, 2011

1.17.2011

2010 Tied for Warmest Year on Record, NASA Research Finds

ScienceDaily — Global surface temperatures in 2010 tied 2005 as the warmest on record, according to an analysis released Jan. 12, 2011 by researchers at NASA's Goddard Institute for Space Studies (GISS) in New York.

The two years differed by less than 0.018 degrees Fahrenheit. The difference is smaller than the uncertainty in comparing the temperatures of recent years, putting them into a statistical tie. In the new analysis, the next warmest years are 1998, 2002, 2003, 2006, 2007 and 2009, which are statistically tied for third warmest year. The GISS records begin in 1880.

The analysis found 2010 approximately 1.34 F warmer than the average global surface temperature from 1951 to 1980. To measure climate change, scientists look at long-term trends. The temperature trend, including data from 2010, shows the climate has warmed by approximately 0.36 F per decade since the late 1970s.

"If the warming trend continues, as is expected, if greenhouse gases continue to increase, the 2010 record will not stand for long," said James Hansen, the director of GISS.

The analysis produced at GISS is compiled from weather data from more than 1000 meteorological stations around the world, satellite observations of sea surface temperature and Antarctic research station measurements. A computer program uses the data to calculate temperature anomalies -- the difference between surface temperature in a given month and the average temperature for the same period during 1951 to 1980. This three-decade period acts as a baseline for the analysis.

The resulting temperature record closely matches others independently produced by the Met Office Hadley Centre in the United Kingdom and the National Oceanic and Atmospheric Administration's National Climatic Data Center.

The record temperature in 2010 is particularly noteworthy, because the last half of the year was marked by a transition to strong La Niña conditions, which bring cool sea surface temperatures to the eastern tropical Pacific Ocean.

"Global temperature is rising as fast in the past decade as in the prior two decades, despite year-to-year fluctuations associated with the El Niño-La Niña cycle of tropical ocean temperature," Hansen and colleagues reported in the Dec. 14, 2010, issue of Reviews of Geophysics.

A chilly spell also struck this winter across northern Europe. The event may have been influenced by the decline of Arctic sea ice and could be linked to warming temperatures at more northern latitudes.

Arctic sea ice acts like a blanket, insulating the atmosphere from the ocean's heat. Take away that blanket, and the heat can escape into the atmosphere, increasing local surface temperatures. Regions in northeast Canada were more than 18 degrees warmer than normal in December.

The loss of sea ice may also be driving Arctic air into the middle latitudes. Winter weather patterns are notoriously chaotic, and the GISS analysis finds seven of the last 10 European winters warmer than the average from 1951 to 1980. The unusual cold in the past two winters has caused scientists to begin to speculate about a potential connection to sea ice changes.

"One possibility is that the heat source due to open water in Hudson Bay affected Arctic wind patterns, with a seesaw pattern that has Arctic air downstream pouring into Europe," Hansen said.

For more information about GISS's surface temperature record, click here

A Warming World

Click here to view: Global Temperatures Animation

Source

11.24.2010

Study into Great Barrier Reef viruses

A SCIENTIST will start the monumental task of sifting through thousands of viruses to determine whether they are friends or foes to the Great Barrier Reef.

While most viruses are considered to be harmful to plants and animals, Australian Institute of Marine Science researcher Madeline van Oppen will examine whether viruses can add any benefit to coral reefs.

It has been estimated 28,000 viruses can live in a single coral colony. However, much is unknown about the effects – if any – they actually have. Some viruses may even contribute to coral bleaching, a condition brought on by stress.

Dr van Oppen has received a prestigious Australian Research Council Future Fellowship, one of 28 awarded across the country, to assist her work.

Much of her field work on coral disease has been carried out on reefs in Far North Queensland.

She hoped her work could provide insights into how corals could respond to climate change.

"What I’ll firstly be doing is describing the diversity of viruses associated with coral disease and trying to figure out what range of roles they play in terms of coral health and disease, and also in the way they can adapt," Dr van Oppen said.

By working out how corals respond to potential stress from viruses, this could, in turn, help contribute to management strategies to strengthen reef health.

Another fellowship recipient was James Cook University researcher Dr Michelle Heupel, who will investigate the migration patterns of sharks and coral trout.

Source: http://www.cairns.com.au/article/2010/11/22/136471_local-news.html

11.01.2010

Better monitoring urged for ailing oceans by 2015

(Reuters) - Ocean scientists urged governments on Sunday to invest billions of dollars by 2015 in a new system to monitor the seas and give alerts of everything from tsunamis to acidification linked to climate change.

They said better oversight would have huge economic benefits, helping to understand the impact of over-fishing or shifts in monsoons that can bring extreme weather such as the 2010 floods in Pakistan.

A scientific alliance, Oceans United, would present the plea to governments meeting in Beijing on Nov. 3-5 for talks about a goal set at a 2002 U.N. Earth Summit of setting up a new system to monitor the health of the planet.

"Most ocean experts believe the future ocean will be saltier, hotter, more acidic and less diverse," said Jesse Ausubel, a founder of the Partnership for Observation of the Global Oceans (POGO), which leads the alliance and represents 38 major oceanographic institutions from 21 nations.

"It is past time to get serious about measuring what's happening to the seas around us," Ausubel said in a statement.

POGO said global ocean monitoring would cost $10 billion to $15 billion to set up, with $5 billion in annual operating costs.

Currently, one estimate is that between $1 and $3 billion are spent on monitoring the seas, said Tony Knap, director of the Bermuda Institute of Ocean Sciences and a leader of POGO.

Knap said new cash sounded a lot at a time of austerity cuts by many governments, but could help avert bigger losses.

JAPAN TSUNAMI
Off Japan, officials estimate an existing $100 million system of subsea cables to monitor earthquakes and tsunamis, linked to an early warning system, will avert 7,500-10,000 of a projected 25,000 fatalities in the event of a huge subsea earthquake.

"It sounds a lot to install $100 million of cables but in terms of prevention of loss of life it begins to look trivial," Knap said.

New cash would help expand many existing projects, such as satellite monitoring of ocean temperatures, tags on dolphins, salmon or whales, or tsunami warning systems off some nations.

Ausubel told Reuters: "The Greeks 2,500 years ago realized that building lighthouses would have great benefits for mariners. Over the centuries, governments have invested in buoys and aids for navigation.

"This is the 21st century version of that," said Ausubel, who is also a vice-president of the Alfred P. Sloan Foundation in the United States.

Source: http://in.reuters.com/article/idINIndia-52573420101031

3.29.2010

Bleaching leaves Lord Howe reef 'on knife-edge'

Parts of the world's most southerly coral reef are under threat after it suffered its largest-recorded bleaching event.

Lord Howe Island is well known for its pristine environment and natural beauty.

The island's isolation has allowed it to develop unique and endemic marine life and the waters contain an unusual mix of tropical, sub-tropical and temperate corals.

But since January the waters around Lord Howe have experienced unusually warmer temperatures. The average rose by two degrees Celsius and the corals are showing the first signs of extensive bleaching.

And unlike the Great Barrier Reef, where corals have been known to recover, the genetically unique reef at Lord Howe could take decades to regenerate.

Peter Harrison from the Southern Cross University says it is the most significant bleaching event ever recorded at Lord Howe Island.

"The significance of this is that Lord Howe Island has the southern-most coral reef, so when that starts to see signs of extensive coral bleaching we know that the climate is definitely changing," he said.

Professor Harrison and a team of scientists have spent the past week diving off Lord Howe Island, assessing the extent of the stress.

In 1998, the reef survived relatively unscathed despite widespread coral bleaching around the world.

This year, not only have the ocean temperatures been higher, but conditions have been unusually calm.

And that has contributed to the significance of the bleaching.

The island's marine park manager, Ian Kerr, says the still conditions meant water was not flushed out of the lagoon.

"So the lagoon especially had higher temperatures than it normally does and higher UV light," he said.

It is not known how much of the reef will recover.

Professor Harrison says some mortality is expected but cooler temperatures over coming months may reduce the stress.

"At the moment we really can't determine whether or not there [will] be serious mortality of corals at some of these sites or not," he said.

"It was personally very upsetting to go back to this absolutely gorgeous reef environment.

"It should be noted that at the moment it is still a beautiful pristine reef environment, but to go back and see so many of these corals bleached was really upsetting to me personally.

"I am hoping that the cooler sea temperatures will allow a decrease in stress and most of these corals come back really quickly and recover fully.

"But at the moment it is on a knife edge."

Source: http://www.abc.net.au/news/stories/2010/03/24/2854437.htm?site=newengland

About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

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2.15.2010

Oceans Reveal Further Impacts of Climate Change

ScienceDaily — The increasing acidity of the world's oceans -- and that acidity's growing threat to marine species -- are definitive proof that the atmospheric carbon dioxide that is causing climate change is also negatively affecting the marine environment, says Antarctic marine biologist Jim McClintock, Ph.D., professor in the University of Alabama at Birmingham (UAB) Department of Biology.

"The oceans are a sink for the carbon dioxide that is released into the atmosphere," says McClintock, who has spent more than two decades researching the marine species off the coast of Antarctica. Carbon dioxide is absorbed by oceans, and through a chemical process hydrogen ions are released to make seawater more acidic.

"Existing data points to consistently increasing oceanic acidity, and that is a direct result of increasing carbon dioxide levels in the atmosphere; it is incontrovertible," McClintock says. "The ramifications for many of the organisms that call the water home are profound."

A substance's level of acidity is measured by its pH value; the lower the pH value, the more acidic is the substance. McClintock says data collected since the pre-industrial age indicates the mean surface pH of the oceans has declined from 8.2 to 8.1 units with another 0.4 unit decline possible by century's end. A single whole pH unit drop would make ocean waters 10 times more acidic, which could rob many marine organisms of their ability to produce protective shells -- and tip the balance of marine food chains.

"There is no existing data that I am aware of that can be used to debate the trend of increasing ocean acidification," he says.

McClintock and three co-authors collected and reviewed the most recent data on ocean acidification at high latitudes for an article in the December 2009 issue of Oceanography magazine, a special issue that focuses on ocean acidification worldwide. McClintock also recently published research that revealed barnacles grown under acidified seawater conditions produce weaker adult shells.

Antarctica as the Ground Zero for Climate Change

McClintock says the delicate balance of life in the waters that surround the frozen continent of Antarctica is especially susceptible to the effects of acidification. The impact on the marine life in that region will serve as a bellwether for global climate-change effects, he says.

"The Southern Ocean is a major global sink for carbon dioxide. Moreover, there are a number of unique factors that threaten to reduce the availability of abundant minerals dissolved in polar seawater that are used by marine invertebrates to make their protective shells," McClintock says.

"In addition, the increased acidity of the seawater itself can literally begin to eat away at the outer surfaces of shells of existing clams, snails and other calcified organisms, which could cause species to die outright or become vulnerable to new predators."

One study McClintock recently conducted with a team of UAB researchers revealed that the shells of post-mortem Antarctic marine invertebrates evidenced erosion and significant loss of mass within only five weeks under simulated acidic conditions.

McClintock says acidification also could exert a toll on the world's fisheries, including mollusks and crustaceans. He adds that the potential loss of such marine populations could greatly alter the oceans' long-standing food chains and produce negative ripple effects on human industries or food supplies over time.

"So many fundamental biological processes can be influenced by ocean acidification, and the change in the oceans' makeup in regions such as Antarctica are projected to occur over a time period measured in decades," McClintock says.

"Evolution simply may be unable to keep up, because it typically takes marine organisms longer periods, hundreds or even thousands of years to naturally adapt," he says. "But ocean acidification is simply happening too quickly for many species to survive unless we reverse the trend of increasing anthropogenically generated carbon dioxide that is in large part driving climate change."

Source: http://www.sciencedaily.com/releases/2010/02/100204144811.htm

About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

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2.11.2010

Climate 'Tipping Points' May Arrive Without Warning, Says Top Forecaster

ScienceDaily — A new University of California, Davis, study by a top ecological forecaster says it is harder than experts thought to predict when sudden shifts in Earth's natural systems will occur -- a worrisome finding for scientists trying to identify the tipping points that could push climate change into an irreparable global disaster.

Many scientists are looking for the warning signs that herald sudden changes in natural systems, in hopes of forestalling those changes, or improving our preparations for them," said UC Davis theoretical ecologist Alan Hastings. "Our new study found, unfortunately, that regime shifts with potentially large consequences can happen without warning — systems can ‘tip’ precipitously.

"This means that some effects of global climate change on ecosystems can be seen only once the effects are dramatic. By that point returning the system to a desirable state will be difficult, if not impossible."

The current study focuses on models from ecology, but its findings may be applicable to other complex systems, especially ones involving human dynamics such as harvesting of fish stocks or financial markets.

Hastings, a professor in the UC Davis Department of Environmental Science and Policy, is one of the world's top experts in using mathematical models (sets of equations) to understand natural systems. His current studies range from researching the dynamics of salmon and cod populations to modeling plant and animal species' response to global climate change.

In 2006, Hastings received the Robert H. MacArthur Award, the highest honor given by the Ecological Society of America.

Hastings' collaborator and co-author on the new study, Derin Wysham, was previously a postdoctoral scholar at UC Davis and is now a research scientist in the Department of Computational and Systems Biology at the John Innes Center in Norwich, England.

Scientists widely agree that global climate change is already causing major environmental effects, such as changes in the frequency and intensity of precipitation, droughts, heat waves and wildfires; rising sea level; water shortages in arid regions; new and larger pest outbreaks afflicting crops and forests; and expanding ranges for tropical pathogens that cause human illness.

And they fear that worse is in store. As U.S. presidential science adviser John Holdren (not an author of the new UC Davis study) recently told a congressional committee: "Climate scientists worry about 'tipping points' ... thresholds beyond which a small additional increase in average temperature or some associated climate variable results in major changes to the affected system."

Among the tipping points Holdren listed were: the complete disappearance of Arctic sea ice in summer, leading to drastic changes in ocean circulation and climate patterns across the whole Northern Hemisphere; acceleration of ice loss from the Greenland and Antarctic ice sheets, driving rates of sea-level increase to 6 feet or more per century; and ocean acidification from carbon dioxide absorption, causing massive disruption in ocean food webs.

The new UC Davis study was supported by the Advancing Theory in Biology program at the U.S. National Science Foundation.

Source: http://www.sciencedaily.com/releases/2010/02/100209191445.htm

About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

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1.25.2010

Bubbles in Ocean to Answer Questions About Climate, Sound, Light

ScienceDaily — The bubbles in your champagne that appear to jump out of your glass and tickle your nose are exhibiting a behavior quite similar to the tiny bubbles found throughout the world's oceans, according to bubble physicist Helen Czerski.

But while the champagne bubbles are likely to raise your spirits, those in the ocean can cause clouds to form and affect the climate.

"Bubbles are little packets of gases that rise or fall and can be carried around as if they're on little conveyor belts," said Czerski, a post-doctoral fellow at the University of Rhode Island Graduate School of Oceanography. "They carry carbon dioxide and oxygen from the atmosphere down into the ocean, and then when they go back up again they pop and sulfur compounds from marine plants are sent upward, forming particles in the air that lead to the formation of clouds."

Czerski is studying how to detect and count ocean bubbles of different sizes to help scientists in other disciplines create more accurate models. She said that scientists have found it difficult to judge the effect of bubbles on their data for years and usually have had to add a "fudge factor" to account for them.

"For instance, bubbles ring like bells when they are formed or when sound waves go past them, and if you're studying sounds traveling through the ocean -- like sounds from whales or sonar -- bubbles can get in the way of what you're trying to listen for," said Czerski, who earned a Ph.D. from Cambridge University before spending a year studying bubbles at Scripps Institution of Oceanography in San Diego and then moving to URI.

"Bubbles also scatter light strongly in the oceans and make things cloudy, so if you're studying light in the ocean you need to understand bubbles," she added.

The URI scientist uses an acoustical resonator to detect and count bubbles of different sizes in the water column. The device can detect bubbles from 3 to 170 microns in size, and she is assessing the accuracy and uncertainty in the measurements.

She recently used the resonator to collect bubble data near the Hawaiian Islands and in the Santa Barbara Channel off Southern California. She counts bubbles down to 10 meters deep -- most bubbles don't go down much further than that, she said. The big ones float back to the surface while the smallest ones gets squeezed out by the pressure as they sink.

"Just after a wave breaks, there are loads of bubbles and they're changing really, really quickly," Czerski explained. "They're stretching and squishing and bumping into each other and breaking into smaller bubbles and they're doing it all too fast for us to see directly. Whenever they break up, each new bubble makes a 'ping' sound, and if you hear it you can say something about those new bubbles."

Czerski said that understanding the physics of bubbles is increasingly important as climate models become more and more refined.

"We need to study bubble distribution and where they go in the water column to understand the exchange of gases that they carry," she said.

According to Czerski, while carbon dioxide and oxygen get carried into the ocean via bubbles, a chemical compound produced by phytoplankton gets carried out of the ocean via bubbles.

"No one really knows why phytoplankton create dimethyl sulfide, but they do, and it passes into bubbles and is carried up and out," she said. "These bubbles supply sulfur to the atmosphere, which acts as a seed for cloud droplets to form.

"Climate is made up of a whole bunch of little things, including bubbles, and these little things matter because there are lots of them," Czerski said.

Czerski began studying bubbles after earning a Ph.D. in a field she described as "blowing things up," which included becoming expert at high-speed photography. She then looked for disciplines in which she could apply this knowledge.

"I've always been fascinated by small things that do stuff that's too fast for us to see," she said. "And I like building experiments that help us see those things."

She learned to scuba dive in order to deploy instruments for measuring bubbles, and she now believes that getting in the water is a vital step for any aspiring bubble scientist.

"You can't really understand what's going on under the sea unless you go there yourself," Czerski concluded. "There is a huge benefit to directly experiencing the world you're studying. The rules are different down there."

Source: http://www.sciencedaily.com/releases/2010/01/100121135853.htm

About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

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1.06.2010

Tipping Elements in the Earth System: How Stable Is the Contemporary Environment?

ScienceDaily — A Special Feature of the Proceedings of the National Academy of Sciences presents the latest scientific insights on so-called tipping elements in the planetary environment. These elements have been identified as the most vulnerable large-scale components of the Earth System that may be profoundly altered by human interference. If one or more of those components is tipped -- especially in the course of global warming -- then the age of remarkably stable environmental conditions on Earth throughout the Holocene may end quickly and irreversibly.

This Special Feature was designed and edited by Hans Joachim Schellnhuber of the Potsdam Institute for Climate Impact Research (PIK). It is meant to make a major contribution to the emerging field of sustainability science. The authors involved analyse altogether eight Earth System components. Three of them, the biggest dust source on our planet, oceanic biogeochemical cycles, and marine methane hydrates, are discussed in depth as potential tipping elements for the first time ever.

"It is the cardinal question of Earth System and sustainability science whether global warming actually triggers singular transformations of crucial components of the planetary machinery," says Schellnhuber. Singular transformations -- as opposed to smooth linear and nonlinear ones -- would dramatically alter the environment in which human civilisations have developed and thrived over many millennia. "Currently, the climate system still operates in the Holocene mode, but the research presented here underlines that a rise of the global mean temperature beyond two degrees Celsius might push the world into singular-change terrain and therefore needs to be avoided," Schellnhuber adds.

The PIK scientist has introduced the tipping-elements concept into the research community some ten years ago. It describes components of the Earth System that could be pushed past critical thresholds by anthropogenic forcing, so that they may "tip" into qualitatively different modes of operation. In a recent seminal paper, Tim Lenton from the University of East Anglia, Hans Joachim Schellnhuber and an international group of colleagues presented a formal definition and compiled a short-list of the nine tipping elements ranked as the most policy-relevant. The current Special Feature examines five of these in much more depth: the El Niño/Southern Oscillation phenomenon, Arctic sea-ice and the great polar ice sheets, the Amazon rainforest, the major monsoon systems, and the circulation of ocean currents in the Atlantic Ocean.

In their article, Matthias Hofmann and Stefan Rahmstorf, also from PIK, discuss the last topic, i.e. the stability properties of the Atlantic Meridional Overturning Circulation (AMOC). The authors present new model simulations of the AMOC response to increased freshwater inflow into the North Atlantic. These challenge the hypothesis that the resulting circulation weakening and the possibility of abrupt oceanic change are just artefacts arising from model flaws. Rather, improving the physical realism of the model leads to a greater vulnerability of the projected AMOC stability.

A group of PIK scientists led by Anders Levermann show that every monsoon circulation inherently bears the possibility of an abrupt collapse. The reason is the moisture-advection feedback which is the core of any monsoon system and was captured in a conceptual model by the authors. The monsoon rains are essential for agriculture as the source of livelihood for several hundred million people in the pertinent regions, the authors state.

David Archer from the University of Chicago and his co-authors provide evidence that methane hydrates in ocean sediments should be regarded as a "slow tipping element" in the Earth's climate system. Global warming of some three degrees Celsius could lead to the escape of more than half of the relevant methane stocks, estimated 940 billion tons of carbon, on a millennial time-scale. This hydrate leakage could cause an additional rise in planetary temperature by 0.5 degrees Celsius. The authors tie this increase in global mean temperature to the methane, but it would persist through many millennia because methane is oxidised in about a decade to carbon dioxide, which continues to impact climate for many millennia.

Ulf Riebesell and colleagues from the Leibniz Institute of Marine Sciences (IFM-GEOMAR) describe the oceans as a climate-system component which is presently undergoing major changes. The sea is not only warming, it is also becoming more acidic. Unbridled anthropogenic emissions of greenhouse gases could alter the cycling of carbon and nutrients in the surface ocean and might damage entire marine ecosystems. The authors conclude that the current level of knowledge allows no clear answer on whether tipping points in the marine ecosphere exist, but they regard some of the projected shifts in oceanic biogeochemistry and their impacts as severe.

Mojib Latif and Noel Keenlyside, also of IFM-GEOMAR, present a review of the complicated mechanisms ruling the El Niño/Southern Oscillation (ENSO) phenomenon. It leads to strong temperature and precipitation fluctuations in the Equatorial Pacific from one year to another and has widespread effects on the global climate system. However, current climate models cannot capture the potential tipping point behaviour of the ENSO phenomenon, the authors resume. Given the potentially huge impacts on biological, chemical and socio-economic systems, the question whether global warming will fundamentally alter the ENSO dynamics in the future has to be investigated further.

A research team led by Richard Washington from the University of Oxford qualifies the biggest dust source on our planet, the Bodélé Depression in Chad, as a potential tipping element. This area in the southern Sahara releases huge plumes, which carry about 700,000 tons of dust towards the Atlantic and the Amazon basin. The authors explain that the so-deployed mineral aerosols play a vital role in transcontinental climatic and biophysical feedbacks. If regional wind patterns or surface erosivities changed due to anthropogenic interference, the dust export from the Bodélé Depression could be substantially modified at time scales as small as one season.

A research team headed by Yadvinder Malhi, also of the University of Oxford, has employed nineteen different global climate models to investigate, whether climate change could cause a large-scale dieback of Amazonian rainforest. The analysis based on a scenario with continuously increasing global emissions of greenhouse gases over the 21st century suggests that dry season water stress is likely to increase in parts of Amazonia. The researchers provide evidence that the Amazonian rainforest could reveal characteristic properties of a tipping element with the tendency to change into a seasonal forest.

In his paper on potential threshold behaviour of sea-ice and continental ice-sheets, Dirk Notz of the Max Planck Institute for Meteorology concludes that tipping points more likely exist for the loss of the Greenland ice sheet and the West-Antarctic ice sheet than for the loss of Arctic sea-ice, which could recover rapidly in a cooler climate. Inland ice could be much more vulnerable to regional warming due to the lack of large internal stabilizing feedbacks as existing for the Arctic sea-ice dynamics. Melting of the continental ice-sheets could lead to rapid multi-meter rise in mean sea level over the coming centuries.

Finally, Nobel Laureate Mario Molina and his co-authors demand fast action from political and economic decision makers to avoid activation of tipping elements. They propose to strengthen the Montreal Protocol regarding substances that have high global-warming potentials. In particular, the scientists make strong cases for an accelerated phasing out of hydrochlorofluorocarbons and a massive reduction of the emissions of soot.

"After two decades of failed climate protection since the 1990 IPCC Report it is more doubtful than ever whether society will manage to confine global environmental change to sub-dangerous levels," says Hans Joachim Schellnhuber. The tipping-elements field is developing quickly into a broad and relevant research frontier domain, but the issues pose tough challenges for contemporary science. Practically none of the planetary cases studied can be either dismissed now -- by firmly ruling out a possible anthropogenic triggering of irregular dynamics -- or settled by providing reliable estimates for activation temperatures and reaction time scales. "Many of the papers sketch the research way forward, but it seems that we will have to live with at least another decade of tantalising ignorance concerning the most worrying potential impacts of global warming," says Schellnhuber.

Source: http://www.sciencedaily.com/releases/2009/12/091209193728.htm

12.18.2009

Toxic algae could be the next big threat

BY LES BLUMENTHAL
McClatchy Newspapers

WASHINGTON -- With a new theory surfacing that toxic algae rather than asteroids killed the dinosaurs, scientists are still trying to unravel the mystery of what caused a massive algae bloom off the Northwest Coast that left thousands of seabirds dead and may have sickened some surfers and kayakers.

The bloom, which stretches roughly 300 miles from Newport, Ore., north to the Canadian border, still persists, though it's a shadow of its September and October peak.

Whipped by waves and storms, the microscopic phytoplankton, which had turned the ocean a rust color, broke apart, releasing toxins and creating meringue-like foam that coated the feathers of birds like spilled oil. Up to 10,000 birds died of hypothermia in September, and researchers are still trying to come up with a count for October.

Researchers are also checking reports that surfers and kayakers who came in contact with the foam may have suffered cold-like symptoms, including temporary loss of smell and taste. The toxins also may have become aerosolized and affected beachcombers. In another strange twist, pathologists performing necropsies found that some of the birds lacked normal bacteria in their stomachs and other internal organs.

"It's definitely a warning sign of something," said Julia Parrish, a professor of aquatic and fishery sciences at the University of Washington. "We don't know what."

Blooms of the single-cell, saltwater algae species known as Akashiwo sanguinea have been found in Puget Sound, the Chesapeake Bay and elsewhere around the world. The bloom off the Northwest coast, however, is huge compared with others. At its height, there were 1.5 million algae cells per quart of water. The bloom was up to 65 feet deep and miles wide.

In only one other instance - a smaller bloom in 2007 in California's Monterey Bay - have the cells broken apart to create a toxic froth. And this particular specie of algae usually likes warmer water than that found off the Northwest Coast.

No one is sure what ignited the bloom. Some scientists think it could be caused by climate change, which has raised ocean temperatures and made the water more acidic - both conditions could favor this algae species. Others say it could be the result of such weather conditions as El Nino or the Pacific decadel oscillation, a long-lived El Nino-like pattern of Pacific climate variability.

The bloom could have been fed by nutrients washed down the Columbia River from farms in eastern Washington and Oregon, or from an ocean condition known as upwelling, where cold water rich with nutrients is pushed toward the surface by the wind.

Or, it could just be the rhythms of the ocean, which scientists are just starting to understand.

"The ocean does have a natural pulse," said Vera Trainer, a Seattle-based research oceanographer for the National Oceanic and Atmospheric Administration. "Is this part of the pulse or is this something different? We want to find out. But some of this is very unusual. We are looking at this very intensely."

Even as Trainer, Parrish and others study the bloom off the Northwest Coast, one of the scientists who developed the theory linking toxic algae to mass extinctions said it fit in with the research he and his partner were working on.

"That's exactly what we are talking about," said John Rodgers, an ecotoxicologist at Clemson University in South Carolina, who along with James Castle, a geologist at Clemson, developed the killer algae theory.

Rodgers was on the road last week in the Midwest, collecting samples of algae to analyze back in his lab. He said he and Castle have found ancient deposits of blue-green algae that produce toxins and deplete oxygen that coincide with five mass extinctions millions of years ago. Though he said algae may not have been the only cause for the extinctions, he said it was a major factor.

The blue-green algae was freshwater algae in ponds, lakes and rivers that could have been ingested by prehistoric animals. The toxins also may have been absorbed by plants that were later eaten by animals or become airborne and breathed in by animals.

"They certainly didn't die on the same day or week," Rodgers said. "This happened over hundreds of years."

Even though there are thousands of species of algae, only several hundred produce toxins, he said.

Though the bloom off the Northwest coast is in salt water rather than fresh water, Rodgers said such blooms were well worth keeping an eye on.

"They are changing, expanding their ranges into places never seen before and in densities never seen before," Rodgers said. "It's hard to ignore, and as the data grows, we are becoming more and more convinced."

Rodgers said his theory has been peer reviewed and is gaining acceptance among scientists.

Current climate conditions are becoming strikingly similar to those that existed during the time of the mass extinctions, he said.

In a paper published in March in the journal Environment Geosciences, Rodgers and Castle wrote that their findings "gives us cause for concern and underscores the importance of careful and strategic monitoring as we move into an era of global climate change."

Scientists studying the bloom off the Northwest are wary when asked about Rodgers' and Castle's theory.

"I would be cautious about it," Trainer said.

Raphael Kudela, a toxic algae expert and ocean sciences professor at the University of California at Santa Cruz, thinks algae blooms such as those off the Northwest Coast are becoming more frequent.

"It is consistent with climate change," Kudela said, adding that a bloom like this in the chilly waters of the Northwest was "very unusual."

As for the killer algae theory, Kudela said, "People who study harmful algae don't dismiss it. But it can't be proved."

Parrish doesn't quite know what to make of the theory that algae killed dinosaurs. Back when life was just starting, she said, algae and other single-cell organisms excreted oxygen that created the atmosphere.

"The claim algae had a humongous effect on the atmosphere is correct," Parrish said. "Whether it caused mass extinctions, I don't know."

Source: http://www.miamiherald.com/news/politics/AP/v-fullstory/story/1379798.html

11.08.2009

Coral Reef Decline - Not Just Overfishing

ScienceDaily — Coral reefs, the rainforests of the sea, feed a large portion of the world's population, protect tropical shorelines from erosion, and harbor animals and plants with great potential to provide new therapeutic drugs. Unfortunately, reefs are now beset by problems ranging from local pollution and overfishing to outbreaks of coral disease and global warming. Although most scientists agree that reefs are in desperate trouble, they disagree strongly over the timing and causes of the coral reef crisis. This is not just an academic exercise, because different answers dictate different strategies for managers and policymakers intent on saving reef ecosystems. The cover story published this month in Geology helps focus the debate.

A team led by Richard Aronson of the Dauphin Island Sea Lab in Alabama took cores through reef frameworks in Belize to reconstruct the history of the reefs over the past several thousand years. Although some scientists have suggested that reefs began their decline centuries ago due to early overfishing, Aronson's team found that coral populations were healthy and vibrant until the 1980s, when they were killed by disease and high sea temperatures. The research effort was supported by the National Geographic Society, the Smithsonian Institution and the National Science Foundation.

As Aronson points out, "Protecting fish populations is important in its own right, but it won't save the corals. Corals are being killed at an unprecedented rate by forces outside local control. Saving coral reefs means addressing global environmental issues--climate change in particular--at the highest levels of government."

Source: http://www.sciencedaily.com/releases/2005/08/050830072609.htm

7.05.2009

Sea Ice At Lowest Level In 800 Years Near Greenland

There has never been so little sea ice in the area between Svalbard and Greenland in the last 800 years. (Credit: NASA/GSFC)

ScienceDaily — New research, which reconstructs the extent of ice in the sea between Greenland and Svalbard from the 13th century to the present indicates that there has never been so little sea ice as there is now. The research results from the Niels Bohr Institute, among others, are published in the scientific journal, Climate Dynamics.

There are of course neither satellite images nor instrumental records of the climate all the way back to the 13th century, but nature has its own 'archive' of the climate in both ice cores and the annual growth rings of trees and we humans have made records of a great many things over the years - such as observations in the log books of ships and in harbour records. Piece all of the information together and you get a picture of how much sea ice there has been throughout time.

Modern research and historic records

"We have combined information about the climate found in ice cores from an ice cap on Svalbard and from the annual growth rings of trees in Finland and this gave us a curve of the past climate" explains Aslak Grinsted, geophysicist with the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

In order to determine how much sea ice there has been, the researchers needed to turn to data from the logbooks of ships, which whalers and fisherman kept of their expeditions to the boundary of the sea ice. The ship logbooks are very precise and go all the way back to the 16th century. They relate at which geographical position the ice was found. Another source of information about the ice are records from harbours in Iceland, where the severity of the winters have been recorded since the end of the 18th century.

By combining the curve of the climate with the actual historical records of the distribution of the ice, researchers have been able to reconstruct the extent of the sea ice all the way back to the 13th century. Even though the 13th century was a warm period, the calculations show that there has never been so little sea ice as in the 20th century.

In the middle of the 17th century there was also a sharp decline in sea ice, but it lastet only a very brief period. The greatest cover of sea ice was in a period around 1700-1800, which is also called the 'Little Ice Age'.

"There was a sharp change in the ice cover at the start of the 20th century," explains Aslak Grinsted. He explains, that the ice shrank by 300.000 km2 in the space of ten years from 1910-1920. So you can see that there have been sudden changes throughout time, but here during the last few years we have had some record years with very little ice extent.

"We see that the sea ice is shrinking to a level which has not been seen in more than 800 years", concludes Aslak Grinsted.

Source: http://www.sciencedaily.com/releases/2009/07/090701102900.htm

Journal reference:

Macias Fauria et al. Unprecedented low twentieth century winter sea ice extent in the Western Nordic Seas since A.D. 1200. Climate Dynamics, 2009; DOI: 10.1007/s00382-009-0610-z

Adapted from materials provided by University of Copenhagen.