Category Archives: oceans

World Bank issues SOS for oceans, backs alliance

NewsDaily: World Bank issues SOS for oceans, backs alliance.

 

By David FogartyPosted 2012/02/24 at 12:41 am EST

SINGAPORE, Feb. 24, 2012 (Reuters) — The World Bank announced on Friday a global alliance to better manage and protect the world’s oceans, which are under threat from over-fishing, pollution and climate change.



Prostate Cancer Survivors
Does Your Hospital Publish Their Prostate Cancer TX Results? We do.
cancercenter.com/cancer-statistics
Fujitsu® Official Site
Free Hard Drive and Free Shipping. Six Months No Payment. Buy Today!
www.ShopFujitsu.com
Air Pollution Control
Custom designed thermal and catalytic oxidizers!
www.thecmmgroup.com
Energy Efficiency Program
Find Out How To Get Your Insulation Rebate From New Mexico Gas Company!
www.nmgco.com

Oceans are the lifeblood of the planet and the global economy, World Bank President Robert Zoellick told a conference on ocean conservation in Singapore. Yet the seas have become overexploited, coastlines badly degraded and reefs under threat from pollution and rising temperatures.

“We need a new SOS: Save Our Seas,” Zoellick said in announcing the alliance.

The partnership would bring together countries, scientific centers, non-governmental groups, international organizations, foundations and the private sector, he said.

The World Bank could help guide the effort by bringing together existing global ocean conservation programs and support efforts to mobilize finance and develop market-mechanisms to place a value on the benefits that oceans provide.

Millions of people rely on oceans for jobs and food and that dependence will grow as the world’s population heads for 9 billion people, underscoring the need to better manage the seas.

Zoellick said the alliance was initially committed to mobilizing at least $300 million in finance.

“Working with governments, the scientific community, civil society organizations, and the private sector, we aim to leverage as much as $1.2 billion to support healthy and sustainable oceans.”

FISH STOCKS

A key focus was understanding the full value of the oceans’ wealth and ecosystem services. Oceans are the top source of oxygen, help regulate the climate, while mangroves, reefs and wetlands are critical to protecting increasingly populous coastal areas against hazards such as storms — benefits that are largely taken for granted.

“Whatever the resource, it is impossible to evolve a plan to manage and grow the resource without knowing its value,” he said.

Another aim was to rebuild at least half the world’s fish stocks identified as depleted. About 85 percent of ocean fisheries are fully exploited, over-exploited or depleted.

“We should increase the annual net benefits of fisheries to between $20 billion and $30 billion. We estimate that global fisheries currently run a net economic loss of about $5 billion per year,” he said.

Participants at the conference spoke of the long-term dividends from ocean conservation and better management of its resources. But that needed economists, bankers and board rooms to place a value on the oceans’ “natural capital”.

“The key to the success of this partnership will be new market mechanisms that value natural capital and can attract private finance,” Abyd Karmali, global head of carbon markets at Bank of America Merrill Lynch, told Reuters.

He pointed to the value in preserving carbon-rich mangrove forests and sea grassbeds and the possibility of earning carbon offsets for projects that conserve these areas.

“The oceans’ stock is in trouble. We have diminished its asset value to a huge degree and poor asset management is poor economics,” Stephen Palumbi, director of the Hopkins Marine Station, Stanford University, told the conference.

(Editing by Robert Birsel)

Laundry Lint Pollutes the World's Oceans

Laundry Lint Pollutes the World’s Oceans – ScienceNOW.

There’s nothing subtle about dryer lint: Clean the fluffy, gray mat off the filter or risk a fire. Washer lint, however, is sneaky. Nearly 2000 polyester fibers can float away, unseen, from a single fleece sweater in one wash cycle, a new study reports. That synthetic lint likely makes its way through sewage treatment systems and into oceans around the world. The consequences of this widespread pollution are still hazy, but environmental scientists say the microscopic plastic fibers have the potential to harm marine life.

The existence of so-called microplastics in marine environments is not, in itself, a revelation. Larger bits of plastic, such as those in the infamous Great Pacific Garbage Patch, gradually break down into microscopic fragments. And minute plastic fibers have turned up before in treated sewage and on beaches. But no one had looked at the issue on a global scale, says ecologist Mark Browne of University College Dublin.

So Browne and his team recruited far-flung colleagues on six continents to scoop sand from 18 beaches. (The scientists had to wear all natural-fiber clothing, lest their own garments shed lint into the samples.) Back in the lab, the researchers painstakingly separated the plastic from the sand—a process that involved, among other things, hand plucking microscopic fibers from filter papers. A chemical analysis showed that nearly 80% of those filaments were made of polyester or acrylic, compounds common in textiles.

Not a single beach was free of the colorful synthetic lint. Each cup (250 milliliters) of sand contained at least two fibers and as many as 31. The most contaminated samples came from areas with the highest human population density, suggesting that cities were an important source of the lint.

Cities come with sewers, and Browne’s team thought the plastic fibers might enter the ocean via sewage. Sure enough, synthetic lint was relatively common in both treated wastewater and in ocean sediments from sites where sewage sludge had been dumped. In all the samples, the fibers were mainly polyester and acrylic, just like the ones from the beaches.

Finally, the researchers wanted to see how synthetic lint got into sewage in the first place. Given its polyester-acrylic composition, they thought clothing and blankets were a good bet. So they purchased a pile of polyester blankets, fleeces, and shirts and commandeered three volunteers’ home washing machines for several months. They collected the wastewater from the machines and filtered it to recover the lint. Each polyester item shed hundreds of fibers per washing, the team reports in the 1 November issue of Environmental Science and Technology.

A polyester sweater may seem cozy and innocent on a winter day, but its disintegrated fibers could be bad news in marine environments, Browne says. Other studies have found that microplastics in the ocean absorb pollutants such as DDT. And Browne’s own work has shown that filter-feeding mussels will consume tiny plastic particles, which then enter the animals’ bloodstreams and even their cells. If the same thing happens in nature, the plastic fibers could “end up on our dinner plates,” incorporated into seafood, Browne warns.

There is still no direct evidence that the fibers—pollutant-tainted or otherwise—harm marine life, but Browne says it’s worth figuring out. He argues that the fibers are “guilty until proven innocent” and says that textile and washing machine manufacturers, as well as sewage treatment plants, should be looking for ways to keep the fibers out of the ocean. Garments that shed less lint, or filters that trap the fibers, might help.

ScienceNOW sent a copy of the study to Patagonia, one popular maker of fleece sweaters. No one was able to review the study and comment before deadline, but spokesperson Jess Clayton said that Patagonia does intend to follow up on the findings with Polartec, its primary supplier of fleece.

Christopher Reddy, an environmental chemist at the Woods Hole Oceanographic Institution in Massachusetts, says it’s still hard to tell where lint pollution fits in the spectrum of environmental problems. It won’t “trump CO2 in the atmosphere” as a priority issue, but he calls the new results “provocative” and says they should trigger follow-up studies that measure the effects of the fibers on marine life. “It never ceases to amaze me that we continue to find more pollutants entering the coastal environment,” he adds. “What else is out there we may be missing?”

Seaweed Kills Corals by Touch

Seaweed With a Deadly Touch – ScienceNOW.

 

Green plague. In Fiji, rarely fished reefs (top) abound with colorful corals, but seaweeds start their invasions in exploited locales (bottom)

“Attack of the killer seaweed” may sound like a cheesy horror flick, but for many coral species, murderous multicellular algae have become real-life villains. A new study of reefs in the South Pacific suggests that some algae can poison coral on contact. This chemical warfare may be increasing the pressure on struggling reef communities worldwide, researchers say.

Along the reefs dotting Fiji, overfishing has pitted corals against algae in a battle royale. On swaths of coastline where fishing is restricted, corals such as the tall and branching Acropora millepora rule, says study co-author Mark Hay, a marine ecologist at the Georgia Institute of Technology in Atlanta.

But where Fijians spear lots of herbivores such as bird-beaked parrotfish, few fish remain to prune back the region’s seaweeds, a blanket term for many types of big algae. These algae then creep in, extending their tendrils over close to 60% of the ocean bottom, Hay estimates, and turning waters a sludgy green. Such “seaweed-covered parking lots” aren’t unique to Fiji, either, he says.

Recent studies have hinted that this ocean greenery may be carrying out a subtle chemical war on sensitive reefs. To investigate this covert struggle, Hay and colleagues strung eight different species of Fijian seaweed across growing corals, including A. millepora colonies. True to the researchers’ suspicions, many of these algal species seemed to wield a poison touch. In less than 2 weeks, the test coral often began to discolor and even die where it rubbed against the seaweeds, the team reports today in the Proceedings of the National Academy of Sciences. Faux seaweeds made of plastic had no such effect.

Hay and colleagues then mashed up several of these seaweeds to identify their killer concoction. The key ingredient turned out to be chemicals called terpenes, which some algae use to sicken fish that feed on them. Terpene extracts alone killed off corals, the researchers found. But some algae seemed to be more liberal with their toxins than others, Hay notes. When one particularly nasty specimen called turtle weed (Chlorodesmis fastigiata) rubs against A. millepora, for instance, wide bands of dying tissue girdle the coral.

This seaweed is so nasty, in fact, that most marine herbivores avoid it on sight—except for one species of rabbitfish that quivers with excitement every time it spots this not-so-common algae. That interaction highlights the importance of prudent fishing practices, he adds. If Fijians developed a particular taste for that one rabbitfish, for instance, turtle weed might begin to grow out of control, launching its bid for world, or at least South Pacific, domination. Hay would like to work with Fijians to identify and protect the herbivores most responsible for trimming back deadly seaweeds, giving sensitive corals a fighting chance.

“It’s certainly a novel finding,” says John Bruno, a marine ecologist at the University of North Carolina, Chapel Hill. But not all seaweeds are poisonous, he adds. Many scientists argue that algae—toxins or no—rarely kill off adult corals en masse. Instead, these opportunistic organisms may simply be capitalizing on the slow death of the invertebrates due to pollution, climate change, or other factors. He adds, however, that the seaweeds Hay and colleagues studied would likely be exceptionally toxic to young, coin-sized corals that have yet to grow big and hale.

Terpenes from seaweed are almost certainly not the only reason for the mysterious global decline of corals, says Jennifer Smith, a marine ecologist at the University of California, San Diego. Most scientists rank overfishing, pollution, and warming oceans among the biggest overall contributors. But corals may suffer from other nasty tricks played by seaweed. In a 2006 study, Smith and colleagues sleuthed out that some California algae could take the epidemic route to domination. In the lab, these seaweeds leak huge quantities of dissolved carbon that then fuels the spread of potentially infectious microbes on coral surfaces. “You can imagine that [algae and corals] have evolved over the years different mechanisms for battling each other and fighting these turf wars,” Smith says.

2011 Sea Ice Minimum at near-record level

2011 Sea Ice Minimum : Image of the Day.

2011 Sea Ice Minimum

acquired September 9, 2011
Color bar for 2011 Sea Ice Minimum
acquired September 1, 2010 – September 30, 2011 download animation (8 MB, QuickTime)

In September 2011, sea ice covering the Arctic Ocean declined to the second-lowest extent on record. Satellite data from NASA and the National Snow and Ice Data Center (NSIDC) showed that the summertime ice cover narrowly avoided a new record low.

The image above was made from observations collected by the Advanced Microwave Scanning Radiometer (AMSR-E) on NASA’s Aqua satellite. The map—which looks down on the North Pole—depicts sea ice extent on September 9, 2011, the date of minimum extent for the year. The animation (link below the image) shows the growth and decline of sea ice from September 2010 to September 2011.

Ice-covered areas range in color from white (highest concentration) to light blue (lowest concentration). Open water is dark blue, and land masses are gray. The yellow outline shows the median minimum ice extent for 1979–2000; that is, areas that were at least 15 percent ice-covered in at least half the years between 1979 and 2000.

Melt season in 2011 brought higher-than-average summer temperatures, but not the unusual weather conditions that contributed to the extreme melt of 2007, the record low. “Atmospheric and oceanic conditions were not as conducive to ice loss this year, but the melt still neared 2007 levels,” said Walt Meier of NSIDC. “This probably reflects loss of multi-year ice in the Beaufort and Chukchi seas, as well as other factors that are making the ice more vulnerable.”

The low sea ice level in 2011 fits the pattern of decline over the past three decades, said Joey Comiso of NASA’s Goddard Space Flight Center. Since 1979, September Arctic sea ice extent has declined by 12 percent per decade.

“The sea ice is not only declining; the pace of the decline is becoming more drastic,” he noted. “The older, thicker ice is declining faster than the rest, making for a more vulnerable perennial ice cover.”

While the sea ice extent did not dip below the record, the area did drop slightly lower than 2007 levels for about ten days in early September 2011. Sea ice “area” differs from “extent” in that it equals the actual surface area covered by ice, while extent includes any area where ice covers at least 15 percent of the ocean.

Arctic sea ice extent on September 9, 2011, was 4.33 million square kilometers (1.67 million square miles). Averaged over the month of September, ice extent was 4.61 million square kilometers (1.78 million square miles). This places 2011 as the second lowest ice extent for both the daily minimum and the monthly average. Ice extent was 2.43 million square kilometers (938,000 square miles) below the 1979 to 2000 average.

Climate models have suggested that the Arctic could lose almost all of its summer ice cover by 2100, but in recent years, ice extent has declined faster than the models predicted.

  1. Further Reading

  2. NASA (2011, October 4) Arctic Sea Ice Continues Decline, Hits 2nd-Lowest Level. Accessed October 4, 2011.
  3. NASA Earth Observatory (n.d.) World of Change: Arctic Sea Ice.
  4. NOAA Climate Watch (2011, October 4) Old Ice Becoming Rare in Arctic. Accessed October 4, 2011.

NASA Earth Observatory images created by Jesse Allen, using AMSR-E sea ice concentration data provided courtesy of the National Snow and Ice Data Center. Caption based on text from Patrick Lynch (NASA) and Katherine Leitzell (NSIDC), edited by Michael Carlowicz.

Instrument: 
Aqua – AMSR-E

Europe's oceans changing at unprecedented rate

Europe’s oceans changing at unprecedented rate: report | Reuters.

LONDON | Tue Sep 13, 2011 3:26pm EDT

(Reuters) – Europe’s seas are changing at an unprecedented rate as ice sheets melt, temperatures rise and marine life migrates due to climate change, a report by the Climate Change and European Marine Ecosystem Research (CLAMER) project warned.

Scientists examined a mass of EU-funded research on the impacts of climate change on Europe’s marine environment and identified the gaps and priorities for future work.

“Change has been clearly visible and is much more rapid than we thought was possible,” Carlo Heip, chair of the CLAMER project and lead author of the report, told Reuters on Tuesday.

Over the past 25 years, sea water temperatures have increased as Arctic sea ice has melted. The combination of rising sea-levels and increased winds has contributed to the erosion of 15 percent of European coasts, the report said.

Warming has speeded up in the past 25 years at around 10 times faster than the average rate of increase in the 20th century, it added.

From 1986 to 2006, sea surface temperature rises for European waters were three to six times higher than the global average.

“Scenario simulations suggest that by the end of the 21st century, the temperature of the Baltic Sea may have increased by 2 to 4 degrees centigrade, the North Sea by 1.7 degrees, and the Bay of Biscay by 1.5 to 5 degrees,” the report said.

Melting ice sheets and glaciers add more uncertainty. Current estimates for 2100 suggest European sea levels could rise 60 cms and up to 1.9 meters at some British coasts.

Sea level rise threatens populations in all low-lying areas of Europe, but countries such as Britain, France and the Netherlands could be less vulnerable because they are rich enough to adopt coastal protection measures.

Changes in the marine food chain have also occurred as organisms have migrated to the Atlantic from the Pacific via seasonal ice-free passages through the Arctic.

While some species can thrive in other oceans, any major upheaval to the marine ecosystem could have devastating effects, the report said.

CLAMER also found that some bacteria strains were becoming more prevalent and could be a potential threat to human health. For example, cholera strains have increased in the North Sea over the past 50 years, perhaps due to temperature change.

Among its many recommendations, CLAMER urged more study of seal-level changes due to ice sheets breaking up or melting, coastal erosion, temperature changes, ocean acidification, marine ecosystems and circulation changes.

“The main message is we need to keep our fingers on the pulse,” said Heip.

The full report is available at: www.clamer.eu/

(Editing by Janet Lawrence)

Arctic Ice Loss at near-record levels & Several Other Reuters Updates

 

 

 

 

 

 

 

 

 

World Atlas ice loss claim exaggerated: scientists | Reuters.

LONDON | Mon Sep 19, 2011 3:27pm EDT

(Reuters) – The Times Atlas of the World exaggerated the rate of Greenland’s ice loss in its thirteenth edition last week, scientists said on Monday.

The atlas, published by HarperCollins, showed that Greenland lost 15 percent of its ice cover over the past 12 years, based on information from the National Snow and Ice Data Center in Colorado in the United States.

The Greenland ice sheet is the second biggest in the world and significant shrinking could lead to a global rise in sea levels.

“While global warming has played a role in this reduction, it is also as a result of the much more accurate data and in-depth research that is now available,” HarperCollins said on its website on Monday.

However, a number of scientists disputed the claim.

“We believe that the figure of a 15 percent decrease in permanent ice cover since the publication of the previous atlas 12 years (ago) is both incorrect and misleading,” said Poul Christoffersen, glaciologist at the Scott Polar Research Institute (SPRI) at the University of Cambridge.

“We concluded that a sizable portion of the area mapped as ice-free in the Atlas is clearly still ice-covered.”

Other scientists agreed.

“These new maps are ridiculously off base, way exaggerated relative to the reality of rapid change in Greenland,” said Jeffrey S. Kargel, senior research scientist at the University of Arizona.

The Times Atlas suggested the Greenland ice sheet has lost 300,000 square kilometers in the past 12 years, at a rate of 1.5 percent per year.

However, measurements suggest this rate is at least 10 times faster than in reality, added J. Graham Cogley, Professor of Geography at Trent University, Ontario, Canada.

“It could easily be 20 times too fast and might well be 50 times too fast,” he added.

Last year, a U.N. committee of climate scientists came under fire for bungling a forecast of when Himalayan glaciers would thaw.

The panel’s 2007 report, the main guide for governments in fighting climate change, included an incorrect projection that all Himalayan glaciers could vanish by 2035, hundreds of years earlier than scientists’ projections.

**************************

Summer Arctic sea ice melt at or near record

(Reuters) – Arctic sea ice this summer melted to a record low extent or will come a close second, two different research institutes said on Tuesday, confirming a trend which could yield an ice-free summer within a decade.

The five biggest melts in a 32-year satellite record have all happened in the past five years, likely a result of both manmade climate change and natural weather patterns.

One impact of an ice-free summer may be disrupted world weather, with hints already as some scientists blame recent chill winters in Europe and North America on warmer, open Arctic seas diverting polar winds south.

Researchers at the University of Bremen in Germany say that this year has already toppled 2007 after sea ice retreated to a record low on September 8.

The U.S.-based National Snow and Ice Data Center (NSIDC) says this year is number two with the melt season all but over before winter returns to the high Arctic.

“I’m increasingly confident it will remain number two,” said Mark Serreze, head of the NSIDC. But the result may be close enough to declare a tie, he added.

Most important than the record was the trend, said University of Bremen’s Georg Heygsterall, referring to how the years since 2007 had all since bigger summer melts than those before.

A tie would echo the World Meteorological Organization’s view on recent rising global temperatures, after it declared 2010 a tie with 1998 and 2005 for the hottest year since such records began about a century and a half ago.

Bremen and NSIDC use satellites to measure microwave radiation from the ice pack, but with slightly different methods: NSIDC can achieve a sharper image, but Bremen to a higher resolution of 6 kilometers compared with 25 km.

TREND

Researchers agree that summer sea ice is disappearing faster than expected.

“An ‘ice-free’ summer Arctic is rapidly on its way. Most data indicate that the models are underestimating the rate of ice-loss,” said Kim Holmen, research director at the Norwegian Polar Institute.

“That means that we see more rapid change than the model scenarios have suggested. It also means that there are processes out there that influence ice that we have yet to understand.”

The summer ice retreat has already reached levels which were forecast three decades from now in models used in the U.N. climate panel’s flagship report four years ago.

The Intergovernmental Panel on Climate Change (IPCC) used models which forecasted an ice-free summer at the end of this century.

But that could happen as early as 2013, according to one of the most aggressive estimates. Other experts predict an ice-free Arctic Ocean in summer anywhere from 2020-2050.

“I still see a high likelihood of a near ice-free Arctic Ocean during summer around 2016, plus or minus three years,” said Wieslaw Maslowski at the California-based Naval Postgraduate School.

More difficult to measure than area is ice thickness, which is also diminishing, most scientists agree.

Researchers at the University of Washington in Seattle calculated ice volume, combining area and thickness, reached a record low last year and would do so again this year.

(Reporting by Gerard Wynn)

***********************

More on Sea-Ice loss:

Thu Sep 15, 2011 3:49pm EDT

<span class="articleLocation”>(Reuters) – Sea ice on the Arctic Ocean shrank to its second-smallest extent since modern records began, in keeping with a long-term trend, the U.S. National Snow and Ice Data Center reported on Thursday.

The annual sea ice minimum was reached on September 9, the center said on its website here in a preliminary finding.

“Changing winds could still push ice flows together reducing ice extend further,” the researchers said. A full analysis will be available in October, when monthly data are available for all of September, which is usually the month when the annual minimum is reached.

Arctic Sea ice is an important sign of a changing climate, and what happens in the Arctic has a major influence on global weather patterns.

At its apparent minimum, sea ice around the North Pole covered 1.67 million square miles (4.33 million square km). That measurement is 61,800 square miles (160,000 square km) above the all-time record low reached in 2007, the center said.

However, it is far below the average minimum for the period 1979 through 2000, according to NSIDC. The satellite record began in 1979.

These figures differ from those reported by the University of Bremen in German, which issued a statement that the Arctic ice reached a record low minimum on September 8.

PATCHES OF WATER AMID THE ICE

Both the University of Bremen and NSIDC use microwave sensors to observe Arctic ice, but these sensors are on different satellites. The Bremen report uses images with higher spatial resolution, according to Walter Meier of NSIDC.

“They can see in more detail, they can see these little patches of water, whereas we see these areas as just ice covered,” Meier said by telephone. He said there can be higher potential for error with these high-resolution images, though there is no evidence of error in this case.

NSIDC’s records go back to 1979; the records used by Bremen go back to 2003. Both indicate the last five years were the least icy in the Arctic sea ice satellite record.

It’s not surprising that this year has not eclipsed the record year of 2007, Meier said.

That year was “a perfect storm” of ice-melting conditions in the Arctic, he said: warmer and sunnier than usual, with extremely warm ocean water and winds all acting in concert.

The fact that 2011 has seen the second-lowest ice extent without these extreme conditions shows a change in the character of the ice cover, Meier said.

Back in 2007, the ice was a consolidated mass which melted from the edges. This year, he said, the ice is more dispersed and the area is dominated by seasonal ice cover — less hardy than multi-year ice — which is more prone to melt.

“Now it doesn’t take as extreme of weather conditions to get to the 2007 ballpark,” Meier said.

(Reporting by Deborah Zabarenko in Washington, Editing by Cynthia Osterman)

 

 

Warming seas could smother seafood

Warming seas could smother seafood – environment – 08 September 2011 – New Scientist.

Seafood could be going off a lot of menus as the world warms. More than half of a group of fish crucial for the marine food web might die if, as predicted, global warming reduces the amount of oxygen dissolved in some critical areas of the ocean – including some of our richest fisheries.

The prediction is based on a unique set of records that goes back to 1951. California has regularly surveyed its marine plankton and baby fish to support the sardine fishery. “There is almost no other dataset going back so far that includes every kind of fish,” says Tony Koslow of the Scripps Institution of Oceanography in La Jolla, California, who heads the survey. The survey records also include information on water temperature, salinity and the dissolved oxygen content.

Koslow’s team studied records of 86 fish species found consistently in the samples and discovered that the abundance of 27 of them correlated strongly with the amount of oxygen 200 to 400 metres down: a 20 per cent drop in oxygen meant a 63 per cent drop in the fish. There have been several episodes of low oxygen during the period in question, mainly in the 1950s and since 1984.

Global climate models predict that 20 to 40 per cent of the oxygen at these depths will disappear over the next century due to warming, says Koslow – mainly because these waters get oxygen by mixing with surface waters. Warmer, lighter surface waters are less likely to mix with the colder, denser waters beneath.

Of the 27 species most affected by low oxygen, says Koslow, 24 were “mesopelagic”: fish that spend the daytime in deep, dark waters below 200 metres to avoid predators such as squid that hunt by sight. There are 10 billion tonnes of mesopelagic fish globally – 10 times the annual global commercial catch – and they are a vital food for other fish and marine birds and mammals.

Out of the depths

In large segments of the Indian, eastern Pacific and Atlantic Oceans called oxygen minimum zones (OMZs), patterns of ocean currents already permit little downward mixing of surface water, so the dark depths where mesopelagics hide have barely enough oxygen for survival. Worldwide, OMZs are expanding both in area and vertically, pushing “hypoxic” water – water with too little oxygen for survival – to ever-shallower levels. Last year, Japanese researchers reported that this has nearly halved the depths inhabited by Pacific cod.

The California coast is an OMZ. When oxygen levels are even lower than usual, the hypoxic zone starts up to 90 metres closer to the surface. This means fish must stay in shallower, more brightly lit water, says Koslow, at greater risk from predators – which, he suspects, is what kills them. In the California data, predatory rockfish in fact boomed during periods of low oxygen.

“This is important work,” says William Gilly of Stanford University’s marine lab in Pacific Grove, California. He studies Humboldt squid, an OMZ predator whose recent movements seem consistent with Koslow’s idea.

“These findings are an example of the kinds of changes we will see more broadly throughout our oceans in coming decades, especially in OMZs,” says Frank Whitney of the Institute of Ocean Sciences in Sidney, British Columbia, Canada. Unfortunately, he notes, water and nutrient movements within OMZs make them among our richest fishing grounds.

Journal reference: Marine Ecology Progress Series, DOI: 10.3354/meps09270

Mystery Fossils Link Fungi to Ancient Mass Extinction

Mystery Fossils Link Fungi to Ancient Mass Extinction | Wired Science | Wired.com.

By Scott K. Johnson, Ars Technica

Of the five mass extinctions in the Earth’s past, one stands above the rest in magnitude: the Permian-Trassic extinction, known as the Great Dying. It saw the disappearance of almost 60 percent of all families, and over 80 percent of all genera — in the ocean, that added up to about 96 percent of all species. The cause of this event, 250 million years in the past, is still a matter of debate.

The most likely culprit is the prolific volcanism of the Siberian Traps— the erupted basalt still covers about 2 million square kilometers — but other events may have also played a role. Evidence for a massive destabilization of methane hydrates on the seafloor (a phenomenon described as “The Big Burp”), ocean anoxia and even contemporary asteroid impacts have all been found.

A couple of recent papers in the journal Geology have brought some new information to the discussion, and may help make the picture just a little bit clearer.

 

One source of significant mystery has been the nature of the organic microfossils that are common in rocks dated to the time of the extinction worldwide. The tiny fossils resemble filamentous colonies of cells, but have evaded positive identification.

Some researchers think they are the remains of fungi, while others argue that they are algae instead. There’s evidence on both sides, but the two scenarios represent very different conditions. The fungus indicates a widespread dying of woody vegetation, while algae suggest extensive swamps forming along river systems.

A paper published this month shows that the microfossils are almost identical morphologically to a group of pathogenic soil fungi that can infect trees. If its authors have identified these correctly, it fits in well with an overall picture showing loss of forests and topsoil. The demise of tree species is clear in pollen studies, and there is a lot of evidence for greatly accelerated soil erosion, including increased sediment deposition in deltas with lots of soil-derived organic debris.

Modern studies show that drought stress and UV damage, both of which could be caused by the massive releases of volcanic gases from the Siberian Traps, can make trees susceptible to fungal infection.

Connecting a fungus to a global mass extinction may seem tenuous, but the authors point out that processes down in the world of the very small are often overlooked in any extinction discussions. They summarize by saying, “There may have been a variety of other globally operating environmental stress factors, but whatever sequence of events triggered ecosystem destabilization on land, the aggressiveness of soil-borne pathogenic fungi must have been an integral factor involved in Late Permian forest decline worldwide.”

Separately, another recent paper has pinned down the timing of the extinction. It’s not considered to have been as sudden as the End Cretaceous extinction that killed off the dinosaurs, but the precise timeline has been tough to get a handle on, and estimates have varied.

The research group looked at some marine Permian-Triassic rocks in China that recorded cyclical global climate patterns. Climate controlled the amount of terrestrial sediment that was deposited in this area, which shows up as changes in grain size through the rock layers. Using a device that measures magnetic susceptibility, they were able to precisely quantify changes in grain size across the rock layers. Together with some uranium-lead isotopic ages, they were able to pick out the orbital cycles that control climate, including the prominent 400,000-year eccentricity cycle, and use them to precisely date the extinction interval.

A couple of interesting things show up in the data. For one, minima in several of the orbital cycles coincide shortly before the start of the extinction period. (Think of three sine waves with different wavelengths — at certain points in time, all three troughs will line up by chance.) That could have made for some unusual climatic conditions. Additionally, the effect of the 100,000-year orbital cycle on climate seems diminished for as long as 2 million years afterward.

It’s dangerous to extrapolate to the big picture from records like this, but there’s enough there to warrant further investigation of the orbital forcings.

In the end, they found that the extinction took 600,000 to 700,000 years to play out. This is consistent with the idea that several events acted in concert to destabilize ecosystems and cause the loss of so many species, meaning a significant length of time would be needed. It was simply a nasty time to be a living thing on planet Earth. Some advice for any time travelers out there — steer well clear of the Great Dying.

Image: Photomicrographic comparison of fossil and modern filamentous fungal structures. A: Sclerotium of modern Rhizoctonia aff. solani, aggregated monilioid hyphae (Paul Cannon/Centre for Agriculture and Biosciences International, CABI). B: Modern R. solani, branched monilioid hyphae (Lane Tredway/American Phytopathological Society). C, D: Late Permian Reduviasporonites stoschianus, branched monilioid hyphae. E: R. stoschianus, aggregated hyphae with dominant narrow cells. F: R. stoschianus, aggregated monilioid hyphae. G: R. stoschianus, segment of small intact disk-like sclerotium. Scale bar for all images is 100 ?m.

See Also:

Citation: Geology, 2011. DOI: 10.1130/G32126.1 and Geology, 2011. DOI: 10.1130/G32178.1

Too late to turn back Rising oceans?

Rising oceans: Too late to turn the tide?.

If sea levels rose to where they were during the Last Interglacial Period, large parts of the Gulf of Mexico region would be under water (red areas), including half of Florida and several Caribbean islands. (Credit: Illustration by Jeremy Weiss)

ScienceDaily (July 18, 2011) — Thermal expansion of seawater contributed only slightly to rising sea levels compared to melting ice sheets during the Last Interglacial Period, a University of Arizona-led team of researchers has found.

The study combined paleoclimate records with computer simulations of atmosphere-ocean interactions and the team’s co-authored paper is accepted for publication in Geophysical Research Letters.

As the world’s climate becomes warmer due to increased greenhouse gases in the atmosphere, sea levels are expected to rise by up to three feet by the end of this century.

But the question remains: How much of that will be due to ice sheets melting as opposed to the oceans’ 332 billion cubic miles of water increasing in volume as they warm up?

For the study, UA team members analyzed paleoceanic records of global distribution of sea surface temperatures of the warmest 5,000-year period during the Last Interglacial, a warm period that lasted from 130,000 to 120,000 years ago.

The researchers then compared the data to results of computer-based climate models simulating ocean temperatures during a 200-year snapshot as if taken 125,000 years ago and calculating the contributions from thermal expansion of sea water.

The team found that thermal expansion could have contributed no more than 40 centimeters — less than 1.5 feet — to the rising sea levels during that time, which exceeded today’s level up to eight meters or 26 feet.

At the same time, the paleoclimate data revealed average ocean temperatures that were only about 0.7 degrees Celsius, or 1.3 degrees Fahrenheit, above those of today.

“This means that even small amounts of warming may have committed us to more ice sheet melting than we previously thought. The temperature during that time of high sea levels wasn’t that much warmer than it is today,” said Nicholas McKay, a doctoral student at the UA’s department of geosciences and the paper’s lead author.

McKay pointed out that even if ocean levels rose to similar heights as during the Last Interglacial, they would do so at a rate of up to three feet per century.

“Even though the oceans are absorbing a good deal of the total global warming, the atmosphere is warming faster than the oceans,” McKay added. “Moreover, ocean warming is lagging behind the warming of the atmosphere. The melting of large polar ice sheets lags even farther behind.”

“As a result, even if we stopped greenhouse gas emissions right now, the Earth would keep warming, the oceans would keep warming, the ice sheets would keep shrinking, and sea levels would keep rising for a long time,” he explained.

They are absorbing most of that heat, but they lag behind. Especially the large ice sheets are not in equilibrium with global climate,” McKay added. ”

Jonathan Overpeck, co-director of the UA’s Institute of the Environment and a professor with joint appointments in the department of geosciences and atmospheric sciences, said: “This study marks the strongest case yet made that humans — by warming the atmosphere and oceans — are pushing the Earth’s climate toward the threshold where we will likely be committed to four to six or even more meters of sea level rise in coming centuries.”

Overpeck, who is McKay’s doctoral advisor and a co-author of the study, added: “Unless we dramatically curb global warming, we are in for centuries of sea level rise at a rate of up to three feet per century, with the bulk of the water coming from the melting of the great polar ice sheets — both the Greenland and Antarctic Ice Sheets.”

According to the authors, the new results imply that 4.1 to 5.8 meters, or 13.5 to 19 feet, of sea level rise during the Last Interglacial period was derived from the Antarctic Ice Sheet, “reemphasizing the concern that both the Antarctic and Greenland Ice Sheets may be more sensitive to warming temperatures than widely thought.”

“The central question we asked was, ‘What are the warmest 5,000 years we can find for all these records, and what was the corresponding sea level rise during that time?'” McKay said.

Evidence for elevated sea levels is scattered all around the globe, he added. On Barbados and the Bahamas, for example, notches cut by waves into the rock six or more meters above the present shoreline have been dated to being 125,000 years old.

“Based on previous studies, we know that the sea level during the Last Interglacial was up to 8.5 meters higher than today,” McKay explained.

“We already knew that the vast majority came from the melting of the large ice sheets in Greenland and Antarctica, but how much could the expansion of seawater have added to that?”

Given that sea surface temperatures were about 0.7 degrees warmer than today, the team calculated that even if the warmer temperatures reached all the way down to 2,000 meters depth — more than 6,500 feet, which is highly unlikely — expansion would have accounted for no more than 40 centimeters, less than a foot and a half.

“That means almost all of the substantial sea level rise in the Last Interglacial must have come from the large ice sheets, with only a small contribution from melted mountain glaciers and small ice caps,” McKay said.

According to co-author Bette Otto-Bliesner, senior scientist at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., getting the same estimate of the role ocean expansion played on sea level rise increases confidence in the data and the climate models.

“The models allow us to attribute changes we observe in the paleoclimate record to the physical mechanisms that caused those changes,” Otto-Bliesner said. “This helps tremendously in being able to distinguish mere correlations from cause-and-effect relationships.”

The authors cautioned that past evidence is not a prediction of the future, mostly because global temperatures during the Last Interglacial were driven by changes in Earth’s orbit around the sun. However, current global warming is driven by increasing greenhouse gas concentrations.

The seasonal differences between the northern and the southern hemispheres were more pronounced during the Last Interglacial than they will be in the future.

“We expect something quite different for the future because we’re not changing things seasonally, we’re warming the globe in all seasons,” McKay said.

“The question is, when we think about warming on a global scale and contemplate letting the climate system change to a new warmer state, what would we expect for the ice sheets and sea levels based on the paleoclimate record? The Last Interglacial is the most recent time when sea levels were much higher and it’s a time for which we have lots of data,” McKay added.

“The message is that the last time glaciers and ice sheets melted, sea levels rose by more than eight meters. Much of the world’s population lives relatively close to sea level. This is going to have huge impacts, especially on poor countries,” he added.

“If you live a meter above sea level, it’s irrelevant what causes the rise. Whether sea levels are rising for natural reasons or for anthropogenic reasons, you’re still going to be under water sooner or later.”

Related Stories


Where did the Gulf's spilt oil and gas go?

Where did the Gulf’s spilt oil and gas go? – environment – 18 July 2011 – New Scientist.

The puzzle over what happened to the oil and gas released during the Deepwater Horizon oil spill in the Gulf of Mexico last year has been partially solved.

Oil is composed of many thousands of different chemicals but the plume that stretched through the Gulf contained relatively few. Now chemists have worked out what happened to the rest.

Christopher Reddy, an environmental chemist at the Woods Hole Oceanographic Institution in Massachusetts, and colleagues, used a remotely operated submarine to collect samples directly from the leaking well in June 2010 and compared these with samples taken from elsewhere in the oil plume.

Reddy likens the oil and gas molecules gushing out of the wellhead to passengers on an elevator. “We wanted to know which compounds got off the elevator instead of going up,” he says.

The team found that water-soluble compounds dissolved in neutrally buoyant seawater about 400 metres above the wellhead. These included benzene, toluene, ethylbenzene and xylene – a toxic suite collectively referred to as BTEX. And in this layer they stayed. By contrast, the compounds that reached the surface were mainly insoluble.

Deep difference

Reddy’s work helps to answer one of the major questions from the oil spill – what happened to all that oil and gas, says David Valentine, a microbial geochemist at the University of California, Santa Barbara.

The results show how deep oil spills differ from surface spills, where many toxic compounds quickly evaporate rather than contaminating the water.

The team’s measurements also show that BTEX concentrations reached up to 78 micrograms per litre. That level is several orders of magnitude higher than known toxicity levels for marine organisms, according to Judith McDowell, a zoologist also at Woods Hole.

Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1101242108