Researchers: Ocean Salinity Change Detected; Wet To Get Wetter, Dry To Get Drier

From Underwater Times: Researchers: Ocean Salinity Change Detected; Wet To Get Wetter, Dry To Get Drier

CLAYTON SOUTH, Victoria -- A clear change in salinity has been detected in the world's oceans, signaling shifts and an acceleration in the global rainfall and evaporation cycle.

In a paper published today in the journal Science, Australian scientists from CSIRO and the Lawrence Livermore National Laboratory, California, reported changing patterns of salinity in the global ocean during the past 50 years, marking a clear fingerprint of climate change.

Lead author, Dr Paul Durack, said that by looking at observed ocean salinity changes and the relationship between salinity, rainfall and evaporation in climate models, they determined the water cycle has strengthened by four percent from 1950-2000. This is twice the response projected by current generation global climate models.

"Salinity shifts in the ocean confirm climate and the global water cycle have changed.

"These changes suggest that arid regions have become drier and high rainfall regions have become wetter in response to observed global warming," said Dr Durack, a post-doctoral fellow at the Lawrence Livermore National Laboratory.

With a projected temperature rise of 3ºC by the end of the century, the researchers estimate a 24 per cent acceleration of the water cycle is possible.

Scientists have struggled to determine coherent estimates of water cycle changes from land-based data because surface observations of rainfall and evaporation are sparse. However, according to the team, global oceans provide a much clearer picture.

"The ocean matters to climate – it stores 97 per cent of the world's water; receives 80 per cent of the all surface rainfall and; it has absorbed 90 per cent of the Earth's energy increase associated with past atmospheric warming," said co-author, Dr Richard Matear of CSIRO's Wealth from Oceans Flagship.

"Warming of the Earth's surface and lower atmosphere is expected to strengthen the water cycle largely driven by the ability of warmer air to hold and redistribute more moisture."

He said the intensification is an enhancement in the patterns of exchange between evaporation and rainfall and with oceans accounting for 71 per cent of the global surface area the change is clearly represented in ocean surface salinity patterns.

In the study, the scientists combined 50-year observed global surface salinity changes with changes from global climate models and found "robust evidence of an intensified global water cycle at a rate of about eight percent per degree of surface warming."

Dr Durack said the patterns are not uniform, with regional variations agreeing with the 'rich get richer' mechanism, where wet regions get wetter and dry regions drier.

He said a change in freshwater availability in response to climate change poses a more significant risk to human societies and ecosystems than warming alone.

"Changes to the global water cycle and the corresponding redistribution of rainfall will affect food availability, stability, access and utilization," Dr Durack said.

Dr Susan Wijffels, co-Chair of the global Argo project and a co-author on the study, said maintenance of the present fleet of around 3,500 profilers is critical to observing continuing changes to salinity in the upper oceans.

The work was funded through the Australian Climate Change Science Program, a joint initiative of the Department of Climate Change and Energy Efficiency, the Bureau of Meteorology and CSIRO. Dr Durack is a graduate of the CSIRO-University of Tasmania Quantitative Marine Science program and he received additional support from CSIRO's Wealth from Oceans Flagship. Work undertaken at Lawrence Livermore National Laboratory is supported by the U.S. Department of Energy under contract DE-AC52-07NA27344.

Scientists: Glowing Belly Helps Tiny Shark Hide From Predators

From Underwater Times: Scientists: Glowing Belly Helps Tiny Shark Hide From Predators

LOUVAIN, Belgium -- Some sharks deserve a blood curdling reputation, but not the diminutive smalleye pygmy shark (Squaliolus aliae). Reaching a maximum length of only 22cm, the tiny animals are more likely to be on someone else's menu. Silhouetted against weak light penetrating from the surface, the tiny sharks should be most at risk from predators approaching from below. However, Julien Claes from Université catholique de Louvain, Belgium, explains that the minute sharks have evolved a handy trick. Their undersides are covered in tiny light-emitting photophores that probably fill in their telltale silhouettes. Adding that the distantly related velvet belly lantern sharks have adopted this luminous tactic for camouflage and communication, Claes and colleague Jérôme Mallefet were curious to discover whether Pygmy sharks had acquired bioluminescence from the same origin, or developed the ability independently. The duo publish their discoveries that pigmy sharks glow for camouflage and that they probably share an ancestor in common with lantern sharks because they use similar mechanisms to regulate their glows in The Journal of Experimental Biology at http://jeb.biologists.com.

Teaming up with Hsuan-Ching Ho from the National Dong Hwa University, Taiwan, the scientists went trawling for smalleye Pygmy sharks off the Taiwanese coast. Back in the lab, the team collected samples of the fish's skin, injected substances – ranging from neurotransmitters to hormones, which are known to regulate a wide range of biological processes – and waited to see whether the skin began glowing. Recording the time when the skin started producing light, and the maximum intensity and duration of light production, the team discovered that the hormone melatonin – which stimulates light production in the lantern sharks – made the smalleye pygmy shark's skin glow, while the neurotransmitters – which regulate light production in deep-sea bony fish – had no effect at all.

However, when the team applied prolactin to the glowing skin, they were in for a surprise: the glow faded. Instead of stimulating 30-min-long bursts of glowing light – as it does for lantern sharks – prolactin dimmed the sharks' glow, which, according to Claes, is intriguing from two perspectives.

He explains that in addition to using continual bioluminescence for camouflage, lantern sharks communicate using bursts of glowing of light from patches of skin on the pectoral and pelvic fins. They regulate this specific form of bioluminescence with the hormone prolactin. Having discovered that smalleye pigmy sharks use prolactin to inhibit light emission and that the photophores were restricted to the shark's lower surface, Claes and Mallefet concluded that instead of using bioluminescence for communication, the smalleye pigmy sharks use it purely for camouflage.

 

Geophysicists Employ Novel Method To Identify Sources Of Global Sea Level Rise

From Underwater Times: Geophysicists Employ Novel Method To Identify Sources Of Global Sea Level Rise TORONTO, Ontario -- As the Earth's climate warms, a melting ice sheet produces a distinct and highly non-uniform pattern of sea-level change, with sea level falling close to the melting ice sheet and rising progressively farther away. The pattern for each ice sheet is unique and is known as its sea level fingerprint. Now, a group of geophysicists from the University of Toronto, Harvard and Rutgers Universities have found a way to identify the sea level fingerprint left by a particular ice sheet, and possibly enable a more precise estimate of its impact on global sea levels. "Our findings provide a new method to distinguish sea-level fingerprints in historical records of sea levels, from other processes such as ocean waves, tides, changes in ocean circulation, and thermal expansion of the ocean," says Carling Hay, a Ph D candidate in the Department of Physics at the University of Toronto and lead author of a study published in Proceedings of the National Academy of Sciences (PNAS). "It may indeed allow us to estimate the contributions of individual ice sheets to rising global sea levels." Scientists around the world are trying to estimate both the current rate of sea level rise and the rates of ice sheet melting, and yet little work has been done to combine the two problems and answer these questions simultaneously. Hay and colleagues Jerry Mitrovica and Eric Morow of Harvard University, and Robert E. Kopp of Rutgers University sought out statistical techniques that had not previously been applied to this problem, and began developing the new method using data analysis techniques common in other fields such as engineering science, economics, and meteorology. The researchers then tested and refined the method by applying it to synthetic data sets – i.e., data sets with the same amount of noise as real data, but with known melting signals. The tests provide important guidance for the application of the method to actual sea-level records. "We are now applying our methodology to historical sea level records to provide a new estimate of total sea level rise and the melt rates of the Greenland and West Antarctic ice sheets, over the 20th century," says Hay. "Preliminary results show intriguing evidence for acceleration of globally averaged sea-level rise in the second half of the period, along with a simultaneous rise in temperature. Once our study of historical records is complete, the next step will be to incorporate satellite-based measurements of sea-level changes." The findings are reported in the paper "Estimating the sources of global sea level rise with data assimilation techniques." The research is supported by funding from the Canadian Institute for Advanced Research, Harvard University, and the US Department of Energy American Association for the Advancement of Science Fellowship Program.

Tribal Group Claims Sea Lions Munch More Salmon Than Previously Thought

From Boise State Public Radio: Tribal Group Claims Sea Lions Munch More Salmon Than Previously Thought A coalition of tribal groups says sea lions are eating far more salmon along the Columbia River than previously thought. The claim comes in a legal fight over whether wildlife officials should be killing some of the hungry sea lions. A federal judge has authorized wildlife officials in Oregon and Washington to kill as many as 30 California sea lions each year near the Bonneville Dam. Four have been killed so far this spring. A conservation group has filed a lawsuit in an attempt to stop the killings. Now, a coalition of tribal groups has filed a legal brief in defense of the program. The tribes claim sea lions are munching even more salmon than fishermen are catching. Doug Hatch is the senior fisheries scientist with the Columbia River Inter-Tribal Fish Commission. He says prior estimates were based solely on observations made near the base of the dam. "That's the only place where there's this program in place to very thoroughly document predation, but predation is happening throughout the lower river," Hatch says. The Humane Society of the United States, which filed the lawsuit, doesn't buy that argument. The group's Sharon Young says sea lions consume the bulk of their fish dinners at the dam, so the current number is accurate.

Range of bacteria found in orcas’ breath

From the Bellingham Herald: Range of bacteria found in orcas’ breath
SEATTLE — The scientists followed the killer whales by boat, trying to catch the precise moment the animals broke the surface.

Then, using a 25-foot pole strung with petri dishes, researchers leaned out and gathered samples of the moist exhaled air that shot like a geyser from each whale’s blowhole.

For four years a team of researchers gathered these orca breath samples from the waters of Washington and British Columbia. And by comparing them to surface waters and orca death records, the scientists stumbled upon a trend, The Seattle Times reported in Friday’s newspaper.

Killer whales – from Puget Sound’s endangered southern residents to the transient whales living hundreds of miles offshore – are inhaling bacteria, fungi and viruses once believed to be found only on land. Some of the pathogens are highly virulent. And some are even antibiotic-resistant.

The discovery comes as researchers also learn that respiratory ailments may be a leading cause of orca deaths, and that leads biologists to a new question:

Given that Puget Sound’s orcas are stressed and potentially more susceptible to illness, how much risk could exposure to new sources of infection pose?

“It’s pretty disturbing and opens a whole new can of worms,” said marine-mammal veterinarian Pete Schroeder. “We have an iconic species of animal that is in danger and whose ability to withstand a severe infection is in question. Now we know they can inhale antibiotic-resistant bacteria, and it can live in their upper respiratory tract.”

The research is so new, it’s hard to draw firm conclusions.

“Just because you detect a particular pathogen, does that mean it will cause a problem? It may or may not,” said Brad Hanson, a marine-mammal biologist with the National Oceanic and Atmospheric Administration’s Northwest Fisheries Science Center in Seattle. “Are we detecting them because we’ve never looked before? We don’t know.”

But while none of the orcas sampled were sick, researchers said their findings suggest that contagions may be of greater concern for orcas than previously thought.

“It means we need to worry about disease outbreaks as a threat to the very survival of the population,” said David Bain, an orca expert and affiliate professor at the University of Washington. “We need to improve the barrier between our lives on land and whales’ lives at sea.”

It’s no secret that a stew of microbes from land regularly invades Puget Sound. Bacteria and nutrients from humans and animals have for decades been funneled into estuaries and bays, causing oxygen problems in Hood Canal and resulting in shellfish-bed closures.

Chicken and cow waste has flowed from farms into rivers. Other nutrients from humans spread through leaky septic tanks or poor sewage treatment or from dumping by pleasure boats or cruise ships. Stormwater runoff over roads and parking lots washes in animal waste with other dangerous chemicals that rise through the food web and settle in the flesh and fat of marine mammals, including orcas.

But in the last decade a largely unheralded potential pollution source has started garnering new attention — the super-thin film that floats atop marine waters, called the sea-surface microlayer. This millimeter-thick sheen on the surface has long been known to carry fungi and bacteria, and those pathogens can easily become airborne.

So in the mid-2000s, after Puget Sound’s orcas were listed for protection under the Endangered Species Act, Schroeder and a group of whale scientists began wondering if the marine mammals could inhale contaminants when they break the surface.

It seemed like an important question. Whale respiration is particularly sensitive. With each breath, humans exchange up to 20 percent of the air in their lungs. Killer whales may exchange 70 percent at once. And whales don’t have a sinus network to extract harmful particles before they settle in the lungs.

Plus, marine biologists suspect Puget Sound’s southern residents already have weakened immune systems. Because they are at the top of the food chain, they’re loaded up with such toxic chemicals as DDT, and the long-lived banned solvent polychlorinated biphenyls (PCBs) found in fish. And the decline of Puget Sound chinook, their preferred food, means they have to work harder for each meal.

While that could make them more vulnerable to disease, scientists rarely know what kills a Puget Sound orca. Only two in the last 10 years have washed up dead in the U.S.

“When southern residents die, most of the time, they just disappear,” Hanson said. “We don’t have a good idea what happens to them.”

So Schroeder and several colleagues got access to a boat. They attached petri dishes to a shaft and followed whales as they traveled in pods. They gathered 23 breath samples from 14 whales, from Puget Sound to Vancouver Island. They also sampled the sea-surface microlayer.

Both the whale breath and the sea-surface samples contained bacteria that didn’t appear to belong there. Some bacteria did belong, but was antibiotic-resistant. There were strains of Salmonella and a rare bacteria known to cause pneumonia in humans. There was a pathogen responsible for gastroenteritis and gangrene, and a form of Staphylococcus resistant to penicillin. One pathogen normally found in marine waters was, surprisingly, resistant to six different antibiotics.

“In some of the bacteria we found some isolates were almost identical to what we recover in dairy cattle,” said Stephen Raverty, a veterinarian pathologist with B.C.’s Ministry of Agriculture.

Many of the bacteria were nonpathogenic, but a few appeared potentially dangerous.

“It’s not like there was a soup of terribly virulent bacteria out there. But there was enough to be concerned,” Schroeder said.

As researchers tried to understand their findings, Raverty and others took on a new challenge — tracking why killer whales die. Of the 222 documented killer-whale strandings in the northeastern Pacific between 1944 and 2003, a thorough analysis had been done on 46 animals. Half of those died while sick with pneumonia.

A Ban on Some Seafood Has Fishermen Fuming

From the New York Times: A Ban on Some Seafood Has Fishermen Fuming
GLOUCESTER, Mass. — Standing on the deck of his rusted steel trawler, Naz Sanfilippo fumed about the latest bad news for New England fishermen: a decision by Whole Foods to stop selling any seafood it does not consider sustainable.

Starting Sunday, gray sole and skate, common catches in the region, will no longer appear in the grocery chain’s artfully arranged fish cases. Atlantic cod, a New England staple, will be sold only if it is not caught by trawlers, which drag nets across the ocean floor, a much-used method here.

“It’s totally maddening,” Mr. Sanfilippo said. “They’re just doing it to make all the green people happy.”

Whole Foods says that, in fact, it is doing its part to address the very real problem of overfishing and help badly depleted fish stocks recover. It is using ratings set by the Blue Ocean Institute, a conservation group, and the Monterey Bay Aquarium in California. They are based on factors including how abundant a species is, how quickly it reproduces and whether the catch method damages its habitat.

“Stewardship of the ocean is so important to our customers and to us,” said David Pilat, the global seafood buyer for Whole Foods. “We’re not necessarily here to tell fishermen how to fish, but on a species like Atlantic cod, we are out there actively saying, ‘For Whole Foods Market to buy your cod, the rating has to be favorable.’ ”

The company had originally planned to stop selling “red-rated” fish next year but moved up its deadline. The other fish it will no longer carry are Atlantic halibut, octopus, sturgeon, tautog, turbot, imported wild shrimp, some species of rockfish, and tuna and swordfish caught in certain areas or by certain methods. (Whole Foods has already stopped selling orange roughy, shark, bluefin tuna and most marlin.)

Although the new policy will affect fishermen nationwide, the reaction from Gloucester and other New England ports may be the unhappiest. New England has more overfished stocks than any other region, according to federal monitors, and its fishing industry has bridled — and struggled to survive — under strict regulations.

“We’ve been murdered,” said Russell Sherman, who sold his entire catch to Whole Foods for the last six years and is seeking new buyers. “It’s not fair at all.”

Jim Ford, who said he sold 700,000 pounds of fish to Whole Foods over the past year, declared, “It’s a marketing ploy, that’s all.” Mr. Ford said he would now sell to the Legal Sea Foods restaurant chain instead.

Whole Foods has had a fish processing plant here since 1996, the oldest of four around the country, and has processed about 10,000 pounds of fish a day here in recent years. A number of local boats have worked with Whole Foods, including a handful that sold exclusively to the company.

Still, Whole Foods is only one buyer, and there will be “plenty of other market demand,” said Vito Giacalone, policy director for the Northeast Seafood Coalition, a trade group here.

“It’s the precedent and the message it sends out that’s really unfortunate,” said Mr. Giacalone, whose family runs a fish auction that sells to Whole Foods. “Whole Foods is a reputable, credible food source for a big community of people, and so when their headquarters makes this kind of statement, it’s not good for the industry.”

Some question the need for grocery stores to reject certain American-caught fish when the government has already imposed its own conservation measures. Many of the nation’s fishermen now operate under federally created systems that allocate a yearly quota of fish.

And for some stocks, the quotas are being reduced; fishermen are facing a 22 percent cut in the amount of Gulf of Maine cod they can catch. In New England, some areas are closed to fishing for part or all of the year; in others, only certain kinds of gear can be used.

“We have the strictest management regime in the world,” said David Goethel, a fisherman from Hampton, N.H. and a member of the New England Fishery Management Council. “So using the word ‘sustainable,’ maybe it looks good in your advertising. But, without being too harsh, it means absolutely nothing.”

But Ellen Pikitch, director of the Institute for Ocean Conservation Science at Stony Brook University, said Whole Foods was doing the right thing.

“Whole Foods is setting a good example by offering fish from relatively well-managed fisheries,” she said. “It’s too bad that more New England fish don’t qualify, but over time, such market forces should help bring these fish back — both in the ocean and to the Whole Foods seafood counter.”

Whole Foods is not the first supermarket chain to limit the kind of seafood it sells in the name of sustainability. Last month, BJ’s Wholesale Club announced a plan to sell seafood only from suppliers “identified as sustainable or on track to meet sustainability standards by 2014.” Other chains are making similar moves.

But in Gloucester, anyway, some fishermen are taking the Whole Foods decision more personally.

Whole Foods will continue to sell New England catches like haddock, pollock, scallops and hake. And it will still sell Atlantic cod that is caught by gillnets or, preferably, hook and line, Mr. Pilat said. While Whole Foods will still sell Pacific cod, he said, it will not appear much in the company’s New England stores for cultural reasons.

“The number of local fish that we will have to discontinue is minimal,” he said, “and we will be replacing those species with other very similar species, such as buying more flounder instead of the gray sole.”

The company is developing relationships with more hook boats, he said. But there are few such boats in the cod fishery, according to the fishery council.

Some fishermen questioned why Whole Foods would approve net-caught fish, as marine mammals are known to get entangled in gillnets, and hook-caught fish, as hooks often end up catching undersize fish. Last week, federal regulators announced that they would ban gillnet fishing for part of the fall in coastal waters from Maine to Cape Ann, Mass., because too many porpoises had been dying in the nets.

“There’s no immaculate fishing gear,” said Mr. Goethel, the fishery council member.

Mr. Sherman said that Whole Foods told him it would still buy pollock and hake from him, but that he could not even offload cod and gray sole at its docks unless it was quickly removed. “They’re talking about my fish like it’s atomic,” he said. “Believe me, they are a great outfit to work for, but they are corporate, and this is a corporate move.”

Mr. Giacalone, while disappointed, did not waste an opportunity to talk about some of the New England-caught fish that will still be available at Whole Foods, starting with pollock. “It’s a great eating fish,” he said. “Almost like the dark meat on a turkey.”

Sperm whales may form clans to fight off orcas

From MSNBC: Sperm whales may form clans to fight off orcas
The threat of killer whales could be why societies of sperm whales in the Atlantic and Pacific differ so much, researchers say.

The sperm whale, the largest toothed whale, possesses the largest brain of any organism on Earth. These leviathans mostly live on giant squid and other creatures of the deep, pursuing them with the most powerful natural sonar known.

The sexes lead very different lives in sperm whales. Males leave their mothers to form ephemeral bachelor groups or to live alone, while females can develop complex societies with multiple levels of organization. At the most basic level of these societies are nearly permanent units of about 10 females that care for and suckle each other's progeny and defend their companions from attack.

Mysteriously, although the female sperm whale societies of the north Atlantic and the east Pacific are genetically similar, their social structures are substantially different. In the Pacific, units of females often temporarily gather with other units of the same clan — groups composed of thousands of females that share distinct patterns of vocal clicks known as codas.

On the other hand, in the Atlantic, there is no evidence of clans, with units of females rarely grouping with others. Also, unit members in the Atlantic are more likely to be related on their mother's side than ones in the Pacific.

Now, researchers suggest these differences could be due to threats from killer whales, also called orcas.

Of the 10 known attacks on sperm whales by killer whales, none took place in the north Atlantic, while six took place in the east Pacific. (The others occurred in the Southern Ocean surrounding Antarctica.) This is despite the fact that researchers have spent more time watching living sperm whales in the Atlantic than in the Pacific.

In the Atlantic, killer whales oddly seem to ignore sperm whales. The researchers suggest this is because killer whales are very much creatures of habit, with clear preferences for specific prey even when other potential targets are available.

" 'Resident' killer whales off the West Coast of the U.S. and Canada disdain the 'wrong' kind of salmon, focusing on chinook rather than pink or other kinds," researcher Hal Whitehead, a marine biologist at Dalhousie University in Halifax, Canada, told LiveScience. "'Pack-ice' killer whales in the Antarctic disdain the 'wrong' kind of seal, focusing on the Weddell seal rather than crabeater seals. These are picky eaters, and their pickiness is almost arbitrary. It seems highly plausible that some of them eat sperm whales; others exclude sperms."

(Killer whales are often grouped by their distribution and eating habits, with resident killer whales foraging on certain foods in the North Pacific.)

The preferences that killer whales have for sperm whales in the Pacific might have led female sperm whale units to group together for safety. This might have eventually led them to form giant clans.

Whaling also may have played a role in these divergences, scientists noted. Female sperm whales living in the Atlantic sites researchers analyzed were virtually untouched by recent mechanized whaling involving harpoon guns; but such mechanized devastation was especially intense in the east Pacific. The destruction of social units in the Pacific may have made them less familial in nature, with survivors (regardless of kinship) banding together.

These social differences might be rooted in part in other factors, researchers noted. For instance, cultural variations that have nothing to do with environment might play a role, but are difficult to pin down definitively. In addition, Atlantic sperm whale sites are generally warmer and less rich in food than Pacific ones — as such, sperm whale grouping might be linked with prey differences, although the dearth of knowledge regarding the deep-sea squid that sperm whales prey on makes it difficult to know for sure.

Future research can focus on distinctions between sperm whales' social behavior in different locations within each ocean, Whitehead said.

The scientists detailed their findings online March 30 in the International Journal of Primatology.