Saturday, December 16, 2006

Fish dance on sulphur cauldrons

By Jonathan Amos
Science reporter, BBC News, San Francisco

These fish thrive in conditions that would kill most other fish

Scientists have witnessed the extreme lifestyle of tonguefish that like to skip across pools of molten sulphur.

The animals - a type of flatfish - were filmed on three expeditions to undersea volcanoes in the western Pacific.

Huge numbers were seen to congregate around the sulphur ponds which well up from beneath the seafloor.

Researchers from the University of Victoria, Canada, are trying to work out how the creatures survive in such a hostile environment.

"There are a lot of toxic heavy metals coming out of these active volcanoes," explained Dr John Dower, a fisheries oceanographer.

As a visual spectacle, it's like something from another planet
Dr Alex Rogers, ZSL
"The water is very warm, and it can be very acidic, the pH can be as low as two like sulphuric acid," he told BBC News.

"And yet here we've got a group that has not previously been seen in this type of environment and they're doing very well - they're actually thriving."

The fish have been studied with remotely operated submersibles, including the Jason II vehicle this year.

Noaa's arc

The area of interest is the Mariana Arc, a 1,200km chain of volcanic seamounts and islands between Guam and Japan.

Positions of seamounts visited in 2006 (with exception of Kasuga-2) (BBC)
It hosts a number of hydrothermal vents - rock systems that draw water through cracks in the seafloor, heat it to temperatures which can be well above 100C, load it with dissolved metals and other chemicals, and then eject the hot fluid back into the ocean.

This type of habitat will support a range of specialised animals such as crabs, shrimp, mussels, and worms - but very few fish. And the flatfish seen on the Mariana Arc seamounts are a first.

"The density of these things is remarkable; we've determined that the abundances are actually about two orders of magnitude (100x) higher than what one typically finds on the continental shelf," said Dr Dower.

"So, these may be the highest flatfish densities seen anywhere, and it raises the puzzling question: what's supporting all that biomass?"

The team thinks the flatfish may be living on resources in the sediments, possibly worms or even bacteria. On one voyage to the vents, the tonguefish were seen to rip apart a dead fish that had fallen out of the water column above - so they may not be too choosy about where their meals come from.

Sulphur skippers

Jason ROV (Noaa)
The Jason vehicle returns after a dive covered in sulphur deposits
What is certainly astonishing is their behaviour around the sulphur pools. The molten material that wells up from beneath the seafloor is denser than the surrounding water and simply lies in ponds in the depressions through which it emerges.

The measured temperature is more than 180C (355F).

"These flatfish live right up against the edge of the pools, and in a couple of cases we saw them out on the surface of a pool," said Dr Dower.

"We have video of a fish sitting on the molten sulphur and then moving off after a couple of minutes, apparently unharmed. They seem to be able to tolerate an environment that no other flatfish, and very few fish in general, are found in."

The deep-sea submersibles captured some of the fish and they are now being analysed.

They have been assigned to the taxonomic genus of Symphurus but they are a species new to science. The team intends to describe their behaviour and ecology in detail in a forthcoming journal paper.

Mariana Arc tonguefish (Noaa)
The largest specimens are less than 11cm (five inches)
They probably feed on worms and vent bacteria
Species is new to science; currently under description
Analysis of their tiny head bones will reveal growth rates
Isotopic (types of atom) tests will determine food sources
Independent scientists who have seen the video of the tonguefish confess to being amazed.

Dr Alex Rogers is a senior research fellow at the Zoological Society of London (ZSL), and recently co-authored a report on the state of seamounts for the United Nations.

"This is stunning," he told BBC News. "The temperatures which these fish are experiencing means they must have remarkable stress defence mechanisms to be able to survive in that environment.

"So physiologically it's remarkable; but as a visual spectacle, it's like something from another planet."

Dr Dower has been talking about the fish here at the American Geophysical Union Fall Meeting.

You can see video of the flatfish by clicking on the Noaa web link.

18 manatees found dead, linked to eating laced seagrass

Given the declining seagrass in Florida, the recurrent red tides, the already heavy threats to manatees, isn't it just great Florida removed them from their endangered species list??? Well the red tide threatens many species, and recently this happened... Its a shame

Eighteen manatee carcasses have been recovered in the Ten Thousand Islands area of Everglades National Park since Nov. 9, and scientists think the animals died from eating red tide-laced seagrass.

Most of the dead manatees were recovered around Chevelier and Huston bays, but some were found as far south as Lostman's River.

"That area averages two manatee deaths a year, so 18 is unusual," said Sara McDonald, a marine research associate at the Florida Fish and Wildlife Research Institute.

National Parks Service officials conducted an aerial survey of the Ten Thousand Islands last Thursday to search for more dead manatees. None were found.

Since July, 24 manatees from Pinellas County to Lee County are suspected to have died from red tide poisoning.

Manatee carcasses are often taken to the state's Marine Mammal Pathobiology Laboratory in St. Petersburg, where scientists perform necropsies - post-mortem examinations.

But transporting the Ten Thousand Island manatees would have taken eight hours, so researchers performed field necropsies.

Because the manatees were badly decomposed, they didn't show the usual red tide symptoms, which include bloody froth from the nose, swollen and bloody kidneys and wet, bloody lungs.

So scientists used a different technique to test stomach, kidney, liver, feces and lung samples of four manatees.

All samples except lung tissues showed toxin in high levels.

"To me, this indicates that these animals were not exposed by inhaling," McDonald said. "The evidence indicates they were likely exposed while feeding in seagrass beds."

Researchers recently discovered that manatees can die from eating seagrass laced with red tide toxin weeks or months after a red tide bloom. Before that, red tide had been thought to kill manatees only when they inhale the toxin at the water's surface.

"We don't know the lethal dose of red tide for manatees," McDonald said. "There are a lot of unanswered questions. We don't know whether a lethal dose comes from chronic exposure or acute exposure or a range from chronic to acute. It's difficult: We can't do controlled experiments where we give doses of red tide to manatees."

©Marco Island Sun Times 2006

Global Warming Trend Continues in 2006, Climate Agencies Say

hey all, sorry I haven't posted in a while... end of semester, busy doing last minute papers and studying for my exams... But considering how warm it still is in NY in december, and the fact that Moscow has not recorded a temperature below freezing yet this season and international ski competitions have been cancelled bc of no snow in Europe, I thought this article would be appropriate...Its from the NY Times...

A decades-long global warming trend that most climate experts say is linked to rising levels of heat-trapping smokestack and tailpipe gases continued apace this year, according to summaries issued yesterday by several national and international climate agencies.

Figures differed slightly, with British weather officials and the World Meteorological Organization, based in Geneva, estimating that 2006 would end up the sixth warmest year since modern records began and NASA scientists putting it fifth.

But all of the reports noted that temperatures greatly above normal were recorded in places as varied as Australia and Scandinavia’s Arctic islands, shattering a variety of longstanding records.

The global climate has warmed and cooled naturally throughout Earth’s history, including a protracted warm spell a millennium ago and a “little ice age” from the 1400s through the 1700s.

But the last 50 years of warming, many climate scientists say, is pressing beyond natural peaks of the last 11,000 years. They say the changes cannot be explained without including a substantial, and growing, push from billions of tons of annual emissions of carbon dioxide and other gases known to trap heat in the air.

The records set this year support various studies that “showed links between human behavior and the warming trend,” said David Parker, a climate scientist at Britain’s Met Office.

England recorded its warmest average annual temperature, 51.5 degrees Fahrenheit, since the Central England Temperature series began in 1659, British officials said.

The contiguous United States had its third warmest year since records began in 1880, according to the analyses. Blistering summer heat contributed to the worst fire season on record, with more than 9.5 million acres burned through early December.

Scientists at NASA’s Goddard Institute for Space Studies said that the Earth’s five warmest years since the late 1880s were, in decreasing order, 2005, 1998, 2002, 2003 and — if no unexpected fluctuations occur the rest of this month — 2006.

James E. Hansen, the director of the Goddard center, said that 2007 was likely to be warmer than this year because one of the periodic hot spells in the tropical Pacific Ocean, called El Niño, has begun and should persist into next spring.

In February, the Intergovernmental Panel on Climate Change will release the main findings of its first update since 2001 on causes of global warming. The previous report concluded that most of the warming since 1950 was probably caused by human activities.

Research and fresh computer simulations considered under the new review have greatly strengthened that link, while also closing in on a possible warming of 5 degrees above the 1990 average, more or less, should the concentration of carbon dioxide double from the longstanding peak measured before the industrial era.

For at least 600,000 years before the Industrial Revolution, the concentration of carbon dioxide rarely nudged beyond 280 parts per million. It is now 382 parts per million and rising steadily.

Without a worldwide shift to nonpolluting energy technologies, such a doubling is considered almost unavoidable given the growth in such emissions in both wealthy and developing countries, but particularly in China and India.

Saturday, December 02, 2006

Scientists: Seagrass Ecosystems at a 'Global Crisis'; Elevating Public Awareness 'Critical' News Service

Washington, D.C. (Dec 1, 2006 14:41 EST) An international team of scientists is calling for a targeted global conservation effort to preserve seagrasses and their ecological services for the world’s coastal ecosystems, according to an article published in the December issue of Bioscience, the journal of the American Institute of Biological Sciences (AIBS).

The article "A Global Crisis for Seagrass Ecosystems" cites the critical role seagrasses play in coastal systems and how costal development, population growth and the resulting increase of nutrient and sediment pollution have contributed to large-scale losses worldwide.

"Seagrasses are the coal mine canaries of coastal ecosystems," said co-author Dr. William Dennison of the University of Maryland Center for Environmental Science. "The fate of seagrasses can provide resource managers advance signs of deteriorating ecological conditions caused by poor water quality and pollution."

Among its findings, the study analyzed an apparent disconnect between the scientific community’s concerns over seagrass habitat and its coverage in the popular media. While recent studies rank seagrass as one of the most valuable habitat in coastal systems, media coverage of other habitats – including salt marshes, mangroves and coral reefs – receive 3 to 100-fold more media attention than seagrass systems.

"Translating scientific understanding of the value of seagrass ecosystems into public awareness, and thus effective seagrass management and restoration, has not been as effective as for other coastal ecosystems, such as salt marshes, mangroves, or coral reefs," said co-author Dr. Robert Orth of the Virginia Institute of Marine Science. "Elevating public awareness about this impending crisis is critical to averting it."

"This report is a call to the world’s coastal managers that we need to do more to protect seagrass habitat," said co-author Dr. Tim Carruthers of the University of Maryland Center for Environmental Science. "Seagrasses are just one of the many keys to maintaining healthy coastal ecosystems and their biodiversity."

Seagrasses – a unique group of flowering plants that have adapted to exist fully submersed in the sea – profoundly influence the physical, chemical and biological environments of coastal waters. They provide critical habitat for aquatic life, alter water flow and can help mitigate the impact of nutrient and sediment pollution.

Seagrasses, thats my thing! It is troubling that these vital coastal ecosystems are disappearing all over the world. And given the state of fisheries, one would expect that critical habitats like seagrass beds would be protected. Unfortunately that is not the case in many places, and even where they are protected, little resources are allotted for restoration and monitoring. This has to change for seagrasses to recover. Check out, its a cool site describing the grasses as well as monitoring and restoration efforts of Long Island seagrass beds.