Yes, oil spills are terrible. But the truth is they're not the calamity doom-mongers say they are
A few names stand out as symbols of Man’s profligacy and carelessness in the environmental hall of infamy.
These must include Torrey Canyon, Amoco Cadiz and Exxon Valdez — huge oil spills that led not to massive loss of human life, but, we are told, to ecological destruction on a scale never before seen. To this list we must now add ‘Deepwater Horizon’, the huge BP drilling platform in the Gulf of Mexico which exploded on April 20.
Since then, around 10-12 million litres of crude oil have been gushing every day from the broken wellhead, a mile down on the seafloor.
Despairing environmentalists, together with politicians and scientists, say that this has led to the greatest ecological disaster in U.S. history with thousands of tonnes of oil set to ruin the pristine shores of the Gulf, kill millions of seabirds, fish and marine mammals, and decimate the lucrative fishing industries of America’s swampy underbelly.
Already, green campaigners have pointed to the spill as yet another sign that modern Man’s dependency on oil amounts to a Faustian pact with an evil subterranean devil; not only does oil wreck our climate when it is burned, releasing warming carbon dioxide into the atmosphere, its very substance amounts to a prehistoric poison unleashed by our demonic technologies.
But the truth is that when it comes to oil spills — and other environmental disasters — history tells us something very puzzling and counter-intuitive.
Despite the appalling pictures beamed onto our screens — the oil-covered seabirds, the grim tides of dead fish, the blackened beaches and disgusting oozing mess at the water’s edge — Nature has seen that, usually within a year or two or even less, places affected by oil spills have returned more or less to normal, the disaster forgotten.
Indeed, many experts now believe that if left to run their natural course, it is likely that the effects of even the worst disasters are nullified.
How can this be? Are oil spills really less bad than we have been led to believe?
Certainly, our attempts to deal with them can often cause far more havoc and destruction than the spills themselves.
In March 1967, the oil tanker Torrey Canyon ran aground off the Scilly Isles en route from the Gulf to Milford Haven.
As the ship foundered and started to break up with its 120,000 tonnes of crude leaking into the Atlantic, the world faced its first major oil-spill disaster. A huge slick was heading for the holiday beaches of Cornwall.
First, the RAF bombed the stricken tanker, in an effort to burn off the oil. Most of the bombs missed and the effect was to accelerate the rate at which oil leaked into the sea.
Next, 10,000 tonnes of industrial-strength detergents were sprayed on the oil by teams on 42 ships in an effort to disperse it all. These chemicals had little effect on the slick, but they poisoned millions of marine organisms and probably caused far more damage to the ecosystem than the oil itself.
At one point, huge drums of detergent were simply poured onto the beaches around Land’s End in the hope that, should the oil wash ashore, this would keep the sands clean. At Sennen Cove, huge quantities of solvent were ploughed into the sand — meaning that the oil was held in situ for months.
There is no doubt that the oil from the Torrey Canyon was toxic and killed a lot of animals, as well as being unsightly. But experts are now convinced that the best solution, short of pumping the oil off the tanker before it could escape or otherwise trying to contain it, would have simply been to do nothing.
According to Dr Simon Boxall, an oceanographer and oil-spill expert at Southampton University: ‘Crude oil is a natural product (being rotting vegetation — albeit modified by age and pressure) and in the environment breaks down naturally through bacterial decay.’
In fact, thousands of tonnes of crude oil, far more than is spilled as a result of man-made disasters, seeps from the seabed naturally every year. The main difference with a ship or oil well disaster is its suddenness and localised nature.
Of course, there is nothing good about an oil spill. If one happens near land, then not only are marine ecosystems threatened but also the fragile coastal ecologies upon which thousands may depend for their livelihood.
The most obvious short-term threat is to tourism; no one wants to lie on a beach sticky with a layer of tar and swim in a sea shining with the telltale rainbow iridescence of floating oil.
Oil spills can kill marine organisms in their millions, and can have a devastating effect on fragile ecosystems such as coral reefs and mangrove swamps. Modern dispersant chemicals are far gentler and more effective than those used in the Torrey Canyon disaster.
But the good news is that these disasters ARE short-term. The environment will recover. And the speed with which it does so depends on the grade of the oil, how much was spilt, the sea temperature, the amount of sunlight, tidal mixing and wave conditions.
What is astonishing is that in most cases, complete recovery takes less than two years.
For example, in December 1999, the MV Erika sank in the Bay of Biscay, and within days a huge oil slick washed up on the beaches of southern Brittany.
News reports showed heartrending pictures of stricken seals as thousands of volunteers battled to clear up the mess.
But despite predictions that the Brittany coast would be ruined for years, the fact was that by the following summer most of the oil had been effectively dispersed and there was certainly no sign of any oil on the beaches when I had a family holiday there less than two years later.
Even more strikingly, when the Braer ran aground off Shetland in 1993, there were widespread predictions of an environmental catastrophe. Some reports suggested that seabird populations could be decimated for 70 years.
In fact, gale-force winds combined with the fact the spill consisted of a very light crude so that, apart from a few hundred affected birds (and some badly-oiled sheep), the environmental effects were so minor that, in the words of marine Biologist Prof Chris Frid of Liverpool University, ‘they were hard to measure’.
Crude oil is a mix of natural hydrocarbons, from light spirits to thick tars. The light oil tends to evaporate quickly and the thicker stuff can be ‘digested’ by marine microbes quite efficiently.
In open oceans, even a large spill will disperse in a few weeks. Closer to shore, there is plenty we can do but we should not overreact.
Oiled seabirds are heartwrenching (and make great TV) but in reality their numbers tend not to be great — birds simply tend to fly away from polluted sea.
Of course, our society depends on oil; until an alternative can be found, it would be foolish to pretend otherwise and in this sense we are all to blame for the Louisiana spill.
Understandably, people living on the Gulf Coast are fearful (and, it must be said, keen to obtain any compensation that may be on offer).
But the fact is these accidents will happen. And the lessons from Nature is that whatever happens from now on, in a couple of years’ time, the silver sands of Florida’s Gulf Coast will be as pristine as they were before the spill.
Friday, May 21, 2010
Feds, Fla. officials differ from scientists on when oil will hit S. Fla., how bad it will be
Feds, Fla. officials differ from scientists on when oil will hit S. Fla., how bad it will be
In Florida — a state accustomed to tracking the minutia of impending hurricanes — forecasting is everything.
But recent forecasts coming from those planning to protect Florida's coast from another potential disaster, the oil relentlessly spewing from the wreck of the Deepwater Horizon, are much different than the forecasts from scientists and environmentalists who study and guard the coast.
The state's emergency responders downplayed the threat to Florida in a briefing for Senate President Jeff Atwater on Wednesday. South Floridians can expect an occasional tar ball to wash ashore, but they probably will never see oil from the recent spill lapping onto beaches, Florida Emergency Management Director David Halstead told Atwater, R-North Palm Beach.
"If we look at two weeks in the Florida sun, most of that is going to be evaporated," Halstead said. "There is a possibility you'll see very little of any sheen ever even make it down all the way to the Keys."
Even if the oil sheen was caught in the Loop Current, environmental damage in South Florida would be "minimal," Doug Darling, the Florida Environmental Preservation Department chief of staff told Atwater.
"If dolphins or manatees swim through it and come up to surface for air, they're going to get a slight coating," Darling said. "But the fish swimming at 100 feet at not affected by it at all."
Scientists do not agree. The marine animals at the greatest danger are those that must surface for air — such as dolphins, manatees and turtles. Every time they surface for air they are covered again in oil and breath the toxic fumes at the surface.
Deepwater marine life are not safe either, experts say.
Chemical dispersants have caused the oil break up and infiltrate the entire water column. That means marine life on the ocean floor, especially corals, could be damaged.
"If oil is floating on the surface, it is not as available to harm things that live on the bottom," said Richard Dodge, dean of Nova Southeastern's Oceanographic Center and head of the National Coral Reef Institute. "If it is dispersed — either by chemicals or nature — the more it will come in contact with other organisms."
Scientists aboard a research vessel who studied the spill for 12 days said Monday that the oil had already entered the loop current and on Tuesday, they forecast it could reach the Florida Keys by Sunday.
Tar balls that washed up on Key West beaches Tuesday were not from the Deepwater Horizon spill, federal officials said. Lab results released Wednesday, after the U.S. Coast Guard flew the samples from Miami to a lab in Groton, Conn., revealed the 50 or so three- to eight-inch tar balls did not come from Deepwater Horizon.
Also on Wednesday, the National Oceanic and Atmospheric Administration confirmed what the academic scientists had been saying since Monday: that the oil is in the loop current, a wobbly current about 80-100 miles from Florida's west coast that will likely push the oil around the Gulf of Mexico, the Florida Straits and into the Gulf Stream that travels up the east coast of the United States and across the Atlantic to Great Britain.
But NOAA predicted it would take at least eight days for the oil to get to Florida.
What difference could four days make? Plenty, experts say. The longer the travel time from the loop current to the Florida Keys, the more time the oil has to evaporate, emulsify and dilute.
In a press release issued on Wednesday, NOAA minimized the danger posed to Florida's coast: "In the time it would take for oil to travel to the vicinity of the Florida Straits, any oil would be highly weathered and both the natural process of evaporation and the application of chemical dispersants would reduce the oil volume significantly."
A day earlier, Congresswoman Kathy Castor — who represents the west coast of Florida — had a different take on the threat to Florida.
"This could be an impending disaster for Florida's Dry Tortugas National Park, the Everglades and the Florida Keys National Marine Sanctuary. These are simply the most unique and diverse ecosystems in the world and a linchpin to our tourism industry, our fishing industry and our way of life in Florida."
Thursday, May 20, 2010
Satellite Images Provide Clear Evidence Gulf Oil Spill In The Loop Current
European Space Agency: Satellite Images Provide Clear Evidence Gulf Oil Spill In The Loop Current
STRASBOURG, France -- Scientists monitoring the US oil spill with ESA's Envisat radar satellite say that it has entered the Loop Current, a powerful conveyor belt that flows clockwise around the Gulf of Mexico towards Florida.
"With these images from space, we have visible proof that at least oil from the surface of the water has reached the current," said Dr Bertrand Chapron of Ifremer, the French Research Institute for Exploitation of the Sea.
Dr Chapron and Dr Fabrice Collard of France's CLS have been combining surface roughness and current flow information with Envisat Advanced Synthetic Aperture Radar (ASAR) data of the area to monitor the proximity of the oil to the current.
In the ASAR image above, acquired on 18 May, a long tendril of the oil spill (outlined in white) extends down into the Loop Current (red arrow).
"We performed advanced processing methods on the images to display surface features like variations in roughness and velocity, which provides insight into the spatial structure of the spill and its transport by surface currents," Dr Collard explained.
From the ASAR images of 12 May and 15 May, the oil spill was observed stretching increasingly closer to the Loop Current, raising concerns that it could reach the current and be carried south towards coral reefs in the Florida Keys.
"Now that oil has entered the Loop Current, it is likely to reach Florida within six days," Dr Chapron said. "Since Envisat ASAR, ERS-2 and other SAR satellites are systematically planned to acquire data over the area, we will monitor the situation continuously."
The scientists warn however that since the Loop Current is a very intense, deep ocean current, its turbulent waters will accelerate the mixing of the oil and water in the coming days.
"This might remove the oil film on the surface and prevent us from tracking it with satellites, but the pollution is likely to affect the coral reef marine ecosystem," Dr Collard said.
Combined efforts using satellite imagery and in-situ measurements of collected water samples will help to assess whether oil is in the deep waters of the ocean.
The Loop Current joins the Gulf Stream — the northern hemisphere's most important ocean-current system — sparking fears that oil could enter this system and be carried up to the US East Coast.
STRASBOURG, France -- Scientists monitoring the US oil spill with ESA's Envisat radar satellite say that it has entered the Loop Current, a powerful conveyor belt that flows clockwise around the Gulf of Mexico towards Florida.
"With these images from space, we have visible proof that at least oil from the surface of the water has reached the current," said Dr Bertrand Chapron of Ifremer, the French Research Institute for Exploitation of the Sea.
Dr Chapron and Dr Fabrice Collard of France's CLS have been combining surface roughness and current flow information with Envisat Advanced Synthetic Aperture Radar (ASAR) data of the area to monitor the proximity of the oil to the current.
In the ASAR image above, acquired on 18 May, a long tendril of the oil spill (outlined in white) extends down into the Loop Current (red arrow).
"We performed advanced processing methods on the images to display surface features like variations in roughness and velocity, which provides insight into the spatial structure of the spill and its transport by surface currents," Dr Collard explained.
From the ASAR images of 12 May and 15 May, the oil spill was observed stretching increasingly closer to the Loop Current, raising concerns that it could reach the current and be carried south towards coral reefs in the Florida Keys.
"Now that oil has entered the Loop Current, it is likely to reach Florida within six days," Dr Chapron said. "Since Envisat ASAR, ERS-2 and other SAR satellites are systematically planned to acquire data over the area, we will monitor the situation continuously."
The scientists warn however that since the Loop Current is a very intense, deep ocean current, its turbulent waters will accelerate the mixing of the oil and water in the coming days.
"This might remove the oil film on the surface and prevent us from tracking it with satellites, but the pollution is likely to affect the coral reef marine ecosystem," Dr Collard said.
Combined efforts using satellite imagery and in-situ measurements of collected water samples will help to assess whether oil is in the deep waters of the ocean.
The Loop Current joins the Gulf Stream — the northern hemisphere's most important ocean-current system — sparking fears that oil could enter this system and be carried up to the US East Coast.
Oceanography: Death and rebirth in the deep
From Nature News: Oceanography: Death and rebirth in the deep
See the actual article at link above for notes.
When a submarine volcano erupts, the results can be devastating — and fascinating. Jane Qiu finds new drama in underwater biogeography.
Richard Lutz, a marine biologist at Rutgers University in New Brunswick, New Jersey, and his colleagues were 2,500 metres beneath the ocean's surface when they encountered the 'blizzard'. It was April 1991, and an underwater ridge, 900 kilometres off the coast of Acapulco, Mexico, was splitting open, introducing 1,200 °C molten rock to 2 °C water. The results were apocalyptic.
While the researchers kept a safe distance from the action in their submersible, the 'snow' of microbial debris blowing around them signalled devastation at the site of the eruption. The bacteria had been thriving at the mouths of hydrothermal vents in the area, extracting energy from the hydrogen sulphide and other chemicals pouring out of the sea bed. In turn, the bacteria nourished a diverse ecosystem of organisms: clams, crabs, mussels and armies of tubeworms. The eruption had laid waste to nearly all of this.
But nature wasn't permanently obliterating life at this site at latitude 9° 50′ N on the East Pacific Rise — rather, it was hitting the reset button. Lutz and his colleagues now had an opportunity to see how life returns to the vents. Putting monitoring equipment in place and returning regularly, they documented the drama of life-after-death as it unfolded. And after 15 years of research, nature repeated the experiment: Nine North, as the researchers call the site, erupted again in 2006.
"It is the only deep-sea location where a full eruptive cycle has been observed," says Lauren Mullineaux, an ecologist at Woods Hole Oceanographic Institution (WHOI) in Massachusetts who has been working at the site. Nine North has allowed marine biologists to identify the first species to return to a vent and the parade of life that follows. And now, four years on from the latest eruption, researchers have begun to answer tougher questions: where do these species come from, how do they travel and how do their populations shift over time?
“Habitat turnover is a window into evolutionary pressures that contribute to speciation.”
But more than that, says Robert Vrijenhoek, a molecular ecologist at the Monterey Bay Aquarium Research Institute in Moss Landing, California, "habitat turnover is a window into evolutionary pressures that contribute to speciation and genetic diversity". By identifying more vent sites around the world, researchers are starting to untangle the intricate interconnectedness between these tiny islands of life scattered through the abyss and separated by vast distances and rugged topography. These sites share similar geological features, with mineral-spewing vents and daunting ridges and valleys. But they don't always share the same species. Researchers are now starting to understand why.
Rapid succession
The first glimpses through the window provided by Nine North revealed a picture of a community rebuilding quickly, says Timothy Shank, a marine biologist at WHOI who collaborates with Lutz (see 'The cycle of life'). The microbial snowfall that piled around the volcano after the 1991 eruption first attracted grazers — shrimps, crabs and fish — both vent and non-vent in origin. Within a year of the eruption, the tubeworms returned. First came Tevnia jerichonana, which thrives at high sulphide concentrations; then, as sulphide levels dwindled in the subsequent year, dense bushes of Riftia pachyptila, the giant tubeworm, took over.
Thousands of these creatures, with sturdy tubes up to two-metres long, created a rich environment for other organisms to inhabit. Snails, and more crabs and swarming shrimps arrived1. It was a never-before-told story of biological succession. But it was unclear whether the organisms taking over the vents were from local sources or came from far away. Nor was it clear whether species composition in the region had changed as a result of the eruption, says Shank, because the area had not been studied in great detail previously.
This is where Mullineaux, a specialist in marine larvae, comes in. Although many vent inhabitants are fused to the sea floor or to other organisms as adults, most spend their early lives as free-swimming larvae that can ride the currents to new homes. She and her team have been studying larvae at Nine North ever since the 1991 eruption. They've collected them at different depths and at the sea floor to get a sense of abundance and species make-up.
As Mullineaux and her colleagues describe in a paper published this year2, the species composition of the larvae at the hydrothermal vents changed markedly after the 2006 eruption. Larvae from species common at the site before the eruption were nowhere to be seen afterwards — even though there were potential sources of recolonization within a few kilometres. By contrast, other species that had been rare became abundant after the catastrophe.
The Woods Hole team also discovered larvae of a species never seen before at Nine North, a rock-clinging snail called Ctenopelta porifera. The nearest hydrothermal system known to host the species is more than 300 kilometres to the north. "This has greatly exceeded our expectation of how far vent larvae could travel in the ocean," says Mullineaux.
Mullineaux's group had in 2001 calculated that a larva with a lifespan of about a month could travel at most up to 100 kilometres from Nine North and that the majority stayed within 60 kilometres3. Even if larvae lived longer, they wouldn't be able to travel farther; the flow of the current reverses every few weeks along the ridge axis and so limits how far larvae could go. How C. porifera had made a 300-kilometre journey was a mystery.
Complex flow
The researchers had based their calculation of flow on measurements of the current at a single location at the crest of the ridge, and assumed that the direction and speed of the currents were the same over the whole area. "This is a reasonable assumption in many parts of the ocean," says Andreas Thurnherr, a physical oceanographer at Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York. But the topography of Nine North disrupts current flow significantly, he says.
To better estimate currents, Thurnherr, Mullineaux and their colleagues placed 15 current-measuring devices along the crest and both flanks of the ridge; they also deployed two mobile current meters that travelled between the sea floor and the top of the ridge, sampling as they went. The team found that currents near the crest of the ridge were faster than those farther away, and that currents on the eastern flank of the ridge flowed southwards, whereas those on the west side went northwards.
Surprisingly, the study shows that currents closer to the sea floor are among the strongest, at about 10 centimetres per second4. This caught the researchers by surprise. "Our observations are markedly different from the much weaker and wider currents we see in many areas of the deep ocean," says Thurnherr. It may also explain how C. porifera larvae could travel so far.
Diane Adams, a former graduate student of Mullineaux's, uncovered another surprise. She had noted a drop in larval abundance at Nine North whenever surface eddies — loops of rotating currents resulting from differences in water density interacting with Earth's rotation — were passing by above.
The researchers hadn't thought that surface eddies could reach down to the ocean floor, but they were able to pick up signals of rotating current loops a short time after surface eddies passed by. "The surface eddies could, in effect, blast larvae off the ridge and have an important role in their dispersal," says Mullineaux.
Such interplay between geology and ocean currents has fascinated researchers of chemosynthetic life for decades. "It's important not only for recolonization after natural disasters but for the evolutionary connectivity of marine life," says Robert Cowen, a marine biologist at the University of Miami in Florida.
Researchers want to know why pockets of life-enabling chemicals in different parts of the ocean host distinct yet overlapping assemblages of species. And where did these species originate? Did they arise first at the vents or perhaps in shallow-water cold seeps — areas where hydrogen sulphide and hydrocarbon sources such as methane leak out from Earth's interior? And how do organisms such as those living off the sulphide-laden oozes of dead whales contribute to the connectivity between chemosynthetic communities?
The key to the divergence and convergence of these marine species during evolution lies in the ability of larvae to negotiate ocean currents, geological barriers and changes in sea-floor topology over millions of years. In this amount of time, the movement of only a small number of larvae is sufficient to allow genetic exchange between geographically separated populations. The scale of such connectivity "can be astonishing", says Charles Fisher, a marine biologist at Pennsylvania State University in University Park.
Long-distance taxi
Fisher's team has found, for example, that some species of tubeworm and mussel living on cold seeps in the Gulf of Mexico are genetically related to their counterparts off the west coast of Nigeria, an indication of genetic exchange between two regions that are more than 10,000 kilometres apart5. This connectivity occurs over numerous generations through steps that are not yet clear. But researchers suspect it may be aided by the equatorial deep jets in the Atlantic, which alternate between easterly and westerly flow depending on depth and so could transport larvae both ways.
In other instances, larval dispersal is blocked over quite short distances, leading to speciation. In the northeastern Pacific Ocean, the 450-kilometre-long Blanco transform fault has separated the Juan de Fuca and Gorda ridge systems, off the coast of Washington State and Oregon (see 'Curiosities of the deep'). Vrijenhoek's team has found that similar-looking snails at Juan de Fuca and Gorda are related, but quite different, species that diverged roughly 11 million years ago, consistent with the time of the fault's formation6.
But, says Vrijenhoek, "the barrier doesn't affect all animals in the same way". The tubeworms at the two ends of the fault, for example, are the same species, even though there are some slight genetic differences7. Gene flow has taken place from populations in the north to their southern counterparts, the same direction as the ocean currents in the region. "Tubeworm larvae probably have a sufficiently long lifespan or stay at the right parts of the water column to allow them to make that jump," he says.
Geological changes may have separated species in other locations as well. For example, the Logatchev hydrothermal vent, located just east of the Caribbean, is the only place in the Mid-Atlantic Ridge known to host vesicomyid clams, which are more typical of the Pacific. Some researchers suspect that the animals might have originated from the Pacific — arriving through an ancient seaway between North and South America before the rise of the isthmus of Panama 5 million years ago.
Other marine biologists, including Cindy Van Dover, a deep-sea biologist at Duke University Marine Laboratory in Beaufort, North Carolina, say that the clam species are probably more common on the Mid-Atlantic Ridge than it looks at present and didn't necessarily originate in the Pacific. "We simply don't have enough samples to know for sure." This highlights a limitation for this relatively young research field: scientists have only a rudimentary knowledge of the distribution of chemosynthetic life, let alone the underlying mechanisms of connectivity and speciation8.
So far, only 200 or so hydrothermal vents and a few dozen cold seeps have been discovered around the world. "Most parts of the ocean are unexplored," says Paul Tyler, a marine biologist at the National Oceanography Centre in Southampton, UK, and chair of the Biogeography of Deep-Water Chemosynthetic Ecosystems (ChEss) programme of the Census of Marine Life, a global initiative to document the biodiversity of the ocean. "Some strategic locations are missing pieces of the puzzle of how things have evolved." These include the Arctic and the Antarctic, where thick ice and turbulent seas make exploration immensely challenging.
Others include the Chile triple junction, where three tectonic plates meet, resulting in the subduction of the Chile rise, a mid-ocean ridge, under the South American plate. "There you have the potential for vents and seeps in close proximity," says Tyler. "This allows you to address the evolutionary relationship between vent and seep animals without the variable of geography."
The great unknown
To many, the Caribbean, especially the little-explored Mid-Cayman rise near the island of Grand Cayman, might hold the key to some of the most perplexing questions in deep-sea biology. At almost 5,000 metres deep, hydrothermal vents in the region should exist at unrecorded environmental extremes and may reveal new species. The location is also ideal for studying the role of the isthmus of Panama in the divergence and connectivity of vent species.
Researchers wonder whether the fauna on the Mid-Cayman rise will be more closely related to that on the East Pacific Rise, on the other side of the Panama land bridge, or to the organisms on the Mid-Atlantic Ridge. Chris German, a marine geochemist at WHOI and co-chair of the ChEss programme, led an expedition in October 2009 that detected signals of hydrothermal plumes near the Mid-Cayman rise. A follow-up expedition by the UK National Oceanography Centre managed to find the vents at a depth of 5,000 metres, the deepest ever recorded. As to what they found there, the team would say little. Nevertheless, German warns to keep expecting surprises. "A few years ago, we thought we knew everything about geological barriers and ocean currents to predict what we are going to find, but we have been wrong every time since."
See the actual article at link above for notes.
When a submarine volcano erupts, the results can be devastating — and fascinating. Jane Qiu finds new drama in underwater biogeography.
Richard Lutz, a marine biologist at Rutgers University in New Brunswick, New Jersey, and his colleagues were 2,500 metres beneath the ocean's surface when they encountered the 'blizzard'. It was April 1991, and an underwater ridge, 900 kilometres off the coast of Acapulco, Mexico, was splitting open, introducing 1,200 °C molten rock to 2 °C water. The results were apocalyptic.
While the researchers kept a safe distance from the action in their submersible, the 'snow' of microbial debris blowing around them signalled devastation at the site of the eruption. The bacteria had been thriving at the mouths of hydrothermal vents in the area, extracting energy from the hydrogen sulphide and other chemicals pouring out of the sea bed. In turn, the bacteria nourished a diverse ecosystem of organisms: clams, crabs, mussels and armies of tubeworms. The eruption had laid waste to nearly all of this.
But nature wasn't permanently obliterating life at this site at latitude 9° 50′ N on the East Pacific Rise — rather, it was hitting the reset button. Lutz and his colleagues now had an opportunity to see how life returns to the vents. Putting monitoring equipment in place and returning regularly, they documented the drama of life-after-death as it unfolded. And after 15 years of research, nature repeated the experiment: Nine North, as the researchers call the site, erupted again in 2006.
"It is the only deep-sea location where a full eruptive cycle has been observed," says Lauren Mullineaux, an ecologist at Woods Hole Oceanographic Institution (WHOI) in Massachusetts who has been working at the site. Nine North has allowed marine biologists to identify the first species to return to a vent and the parade of life that follows. And now, four years on from the latest eruption, researchers have begun to answer tougher questions: where do these species come from, how do they travel and how do their populations shift over time?
“Habitat turnover is a window into evolutionary pressures that contribute to speciation.”
But more than that, says Robert Vrijenhoek, a molecular ecologist at the Monterey Bay Aquarium Research Institute in Moss Landing, California, "habitat turnover is a window into evolutionary pressures that contribute to speciation and genetic diversity". By identifying more vent sites around the world, researchers are starting to untangle the intricate interconnectedness between these tiny islands of life scattered through the abyss and separated by vast distances and rugged topography. These sites share similar geological features, with mineral-spewing vents and daunting ridges and valleys. But they don't always share the same species. Researchers are now starting to understand why.
Rapid succession
The first glimpses through the window provided by Nine North revealed a picture of a community rebuilding quickly, says Timothy Shank, a marine biologist at WHOI who collaborates with Lutz (see 'The cycle of life'). The microbial snowfall that piled around the volcano after the 1991 eruption first attracted grazers — shrimps, crabs and fish — both vent and non-vent in origin. Within a year of the eruption, the tubeworms returned. First came Tevnia jerichonana, which thrives at high sulphide concentrations; then, as sulphide levels dwindled in the subsequent year, dense bushes of Riftia pachyptila, the giant tubeworm, took over.
Thousands of these creatures, with sturdy tubes up to two-metres long, created a rich environment for other organisms to inhabit. Snails, and more crabs and swarming shrimps arrived1. It was a never-before-told story of biological succession. But it was unclear whether the organisms taking over the vents were from local sources or came from far away. Nor was it clear whether species composition in the region had changed as a result of the eruption, says Shank, because the area had not been studied in great detail previously.
This is where Mullineaux, a specialist in marine larvae, comes in. Although many vent inhabitants are fused to the sea floor or to other organisms as adults, most spend their early lives as free-swimming larvae that can ride the currents to new homes. She and her team have been studying larvae at Nine North ever since the 1991 eruption. They've collected them at different depths and at the sea floor to get a sense of abundance and species make-up.
As Mullineaux and her colleagues describe in a paper published this year2, the species composition of the larvae at the hydrothermal vents changed markedly after the 2006 eruption. Larvae from species common at the site before the eruption were nowhere to be seen afterwards — even though there were potential sources of recolonization within a few kilometres. By contrast, other species that had been rare became abundant after the catastrophe.
The Woods Hole team also discovered larvae of a species never seen before at Nine North, a rock-clinging snail called Ctenopelta porifera. The nearest hydrothermal system known to host the species is more than 300 kilometres to the north. "This has greatly exceeded our expectation of how far vent larvae could travel in the ocean," says Mullineaux.
Mullineaux's group had in 2001 calculated that a larva with a lifespan of about a month could travel at most up to 100 kilometres from Nine North and that the majority stayed within 60 kilometres3. Even if larvae lived longer, they wouldn't be able to travel farther; the flow of the current reverses every few weeks along the ridge axis and so limits how far larvae could go. How C. porifera had made a 300-kilometre journey was a mystery.
Complex flow
The researchers had based their calculation of flow on measurements of the current at a single location at the crest of the ridge, and assumed that the direction and speed of the currents were the same over the whole area. "This is a reasonable assumption in many parts of the ocean," says Andreas Thurnherr, a physical oceanographer at Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York. But the topography of Nine North disrupts current flow significantly, he says.
To better estimate currents, Thurnherr, Mullineaux and their colleagues placed 15 current-measuring devices along the crest and both flanks of the ridge; they also deployed two mobile current meters that travelled between the sea floor and the top of the ridge, sampling as they went. The team found that currents near the crest of the ridge were faster than those farther away, and that currents on the eastern flank of the ridge flowed southwards, whereas those on the west side went northwards.
Surprisingly, the study shows that currents closer to the sea floor are among the strongest, at about 10 centimetres per second4. This caught the researchers by surprise. "Our observations are markedly different from the much weaker and wider currents we see in many areas of the deep ocean," says Thurnherr. It may also explain how C. porifera larvae could travel so far.
Diane Adams, a former graduate student of Mullineaux's, uncovered another surprise. She had noted a drop in larval abundance at Nine North whenever surface eddies — loops of rotating currents resulting from differences in water density interacting with Earth's rotation — were passing by above.
The researchers hadn't thought that surface eddies could reach down to the ocean floor, but they were able to pick up signals of rotating current loops a short time after surface eddies passed by. "The surface eddies could, in effect, blast larvae off the ridge and have an important role in their dispersal," says Mullineaux.
Such interplay between geology and ocean currents has fascinated researchers of chemosynthetic life for decades. "It's important not only for recolonization after natural disasters but for the evolutionary connectivity of marine life," says Robert Cowen, a marine biologist at the University of Miami in Florida.
Researchers want to know why pockets of life-enabling chemicals in different parts of the ocean host distinct yet overlapping assemblages of species. And where did these species originate? Did they arise first at the vents or perhaps in shallow-water cold seeps — areas where hydrogen sulphide and hydrocarbon sources such as methane leak out from Earth's interior? And how do organisms such as those living off the sulphide-laden oozes of dead whales contribute to the connectivity between chemosynthetic communities?
The key to the divergence and convergence of these marine species during evolution lies in the ability of larvae to negotiate ocean currents, geological barriers and changes in sea-floor topology over millions of years. In this amount of time, the movement of only a small number of larvae is sufficient to allow genetic exchange between geographically separated populations. The scale of such connectivity "can be astonishing", says Charles Fisher, a marine biologist at Pennsylvania State University in University Park.
Long-distance taxi
Fisher's team has found, for example, that some species of tubeworm and mussel living on cold seeps in the Gulf of Mexico are genetically related to their counterparts off the west coast of Nigeria, an indication of genetic exchange between two regions that are more than 10,000 kilometres apart5. This connectivity occurs over numerous generations through steps that are not yet clear. But researchers suspect it may be aided by the equatorial deep jets in the Atlantic, which alternate between easterly and westerly flow depending on depth and so could transport larvae both ways.
In other instances, larval dispersal is blocked over quite short distances, leading to speciation. In the northeastern Pacific Ocean, the 450-kilometre-long Blanco transform fault has separated the Juan de Fuca and Gorda ridge systems, off the coast of Washington State and Oregon (see 'Curiosities of the deep'). Vrijenhoek's team has found that similar-looking snails at Juan de Fuca and Gorda are related, but quite different, species that diverged roughly 11 million years ago, consistent with the time of the fault's formation6.
But, says Vrijenhoek, "the barrier doesn't affect all animals in the same way". The tubeworms at the two ends of the fault, for example, are the same species, even though there are some slight genetic differences7. Gene flow has taken place from populations in the north to their southern counterparts, the same direction as the ocean currents in the region. "Tubeworm larvae probably have a sufficiently long lifespan or stay at the right parts of the water column to allow them to make that jump," he says.
Geological changes may have separated species in other locations as well. For example, the Logatchev hydrothermal vent, located just east of the Caribbean, is the only place in the Mid-Atlantic Ridge known to host vesicomyid clams, which are more typical of the Pacific. Some researchers suspect that the animals might have originated from the Pacific — arriving through an ancient seaway between North and South America before the rise of the isthmus of Panama 5 million years ago.
Other marine biologists, including Cindy Van Dover, a deep-sea biologist at Duke University Marine Laboratory in Beaufort, North Carolina, say that the clam species are probably more common on the Mid-Atlantic Ridge than it looks at present and didn't necessarily originate in the Pacific. "We simply don't have enough samples to know for sure." This highlights a limitation for this relatively young research field: scientists have only a rudimentary knowledge of the distribution of chemosynthetic life, let alone the underlying mechanisms of connectivity and speciation8.
So far, only 200 or so hydrothermal vents and a few dozen cold seeps have been discovered around the world. "Most parts of the ocean are unexplored," says Paul Tyler, a marine biologist at the National Oceanography Centre in Southampton, UK, and chair of the Biogeography of Deep-Water Chemosynthetic Ecosystems (ChEss) programme of the Census of Marine Life, a global initiative to document the biodiversity of the ocean. "Some strategic locations are missing pieces of the puzzle of how things have evolved." These include the Arctic and the Antarctic, where thick ice and turbulent seas make exploration immensely challenging.
Others include the Chile triple junction, where three tectonic plates meet, resulting in the subduction of the Chile rise, a mid-ocean ridge, under the South American plate. "There you have the potential for vents and seeps in close proximity," says Tyler. "This allows you to address the evolutionary relationship between vent and seep animals without the variable of geography."
The great unknown
To many, the Caribbean, especially the little-explored Mid-Cayman rise near the island of Grand Cayman, might hold the key to some of the most perplexing questions in deep-sea biology. At almost 5,000 metres deep, hydrothermal vents in the region should exist at unrecorded environmental extremes and may reveal new species. The location is also ideal for studying the role of the isthmus of Panama in the divergence and connectivity of vent species.
Researchers wonder whether the fauna on the Mid-Cayman rise will be more closely related to that on the East Pacific Rise, on the other side of the Panama land bridge, or to the organisms on the Mid-Atlantic Ridge. Chris German, a marine geochemist at WHOI and co-chair of the ChEss programme, led an expedition in October 2009 that detected signals of hydrothermal plumes near the Mid-Cayman rise. A follow-up expedition by the UK National Oceanography Centre managed to find the vents at a depth of 5,000 metres, the deepest ever recorded. As to what they found there, the team would say little. Nevertheless, German warns to keep expecting surprises. "A few years ago, we thought we knew everything about geological barriers and ocean currents to predict what we are going to find, but we have been wrong every time since."
Wednesday, May 19, 2010
Reports of underwater oil are exaggerated, officials say
Reports of underwater oil are exaggerated, officials say
HOUMA — Federal marine scientists said media reports of underwater oil plumes observed by scientists aboard a local research vessel, the Pelican, created an inaccurate picture of vast amounts of crude lurking beneath the surface of the Gulf of Mexico.
Some information “was misleading, premature and, in some cases, inaccurate,” Jane Lubchenco, administrator of the National Oceanic and Atmospheric Administration, said Monday. The scientists aboard the vessel, which is based at the Louisiana Universities Marine Consortium in Cocodrie, were drafted by NOAA to do research on the spill.
Scientists along the Gulf Coast are worried that the unprecedented deep-water use of chemicals called dispersants could be keeping toxic crude below the surface. The New York Times and other news outlets reported that scientists aboard the Pelican found “enormous oil plumes in the deep waters of the Gulf of Mexico, including one as large as 10 miles long, 3 miles wide and 300 feet thick in spots.”
While particles of oil suspended in water were found, federal scientists are still testing how much oil might be underwater and whether dispersants are the cause, Lubchenco said.
More than 560,000 gallons of chemicals have been applied to disperse the oil on the surface and deep in the Gulf. Diffusing and sinking the oil is protecting the coast, scientists say, but could be causing deep-sea impacts. The submerged oil could sink and coat corals and other reef organisms and smother them.
Dispersants are typically applied on the surface, but the U.S. Environmental Protection Agency approved their underwater use Friday in hopes of combating the leak of millions of gallons of oil from the site of the Deepwater Horizon rig disaster. The rig exploded April 20, killing 11 workers and initiating a massive leak from a well on the sea floor. Workers began injecting the dispersants near the site of the spewing oil in an attempt to limit the amount of crude that reaches the surface.
The chemicals work by breaking the oil into individual droplets that oil-destroying bacteria can break down faster than a solid slick, said Kerry St. Pé, director of the Barataria-Terrebonne National Estuary Program and former head of the state's oil-spill response team. The dispersed oil sinks and moves with the current but is not impacted by surface winds.
Dispersants are toxic, but their use is a trade off and has probably helped keep oil off Louisiana's shore in large volumes, St. Pé said.
“The dispersed oil is probably impacting marine life in the open ocean, and those impacts shouldn't be taken lightly. But those impacts are less than if the oil had come into our estuaries,” St. Pé said.
The presence of giant columns of oil just beneath the surface of the water is unverified by data, Lubchenco said. Scientists aboard the Pelican also found low oxygen levels in the water, but Lubchenco said they were not low enough to be a source of concern. Lubchenco also said there's no evidence to connect the findings and use of underwater dispersants.
“There's no solid scientific evidence that there are these large undersea plumes,” said Charlie Henry, an environmental scientist with NOAA's emergency-response team.
He said scientists were able to find the basic compounds of oil, hydrocarbons, in the water columns, but the data is still being analyzed. In the meantime, NOAA is doing “a number of things to locate oil before it has an adverse impact.” The agency is conducting extensive water sampling and dropping “crab pots” of absorbent material to check for oil under the surface. Researchers are also dropping trawls up to 100 feet underwater to look for oil.
“It will be a long time before we have all the information,” Henry said. “We're looking hard to paint the whole picture, and we're taking a lot of effort and time to analyze and study it.”
He added that the oil on the surface is “the thinnest I've seen yet,” and credited the use of dispersants.
St. Pé said dispersants are the likely reason a relatively small amount of oil has come ashore. He oversaw the application of dispersants to oil spills 20 years ago and said there are strict protocols that must be followed before the chemicals are used.
But he added that applying dispersant near the bottom of the Gulf carries a lot of unknowns.
“It's cold down there, and no one has quantified the impact of those cold temperatures on dispersed oil,” he said, adding that the cold could reduce the breakdown of oil by bacteria, much like a refrigerator keeps food from decaying for longer. That could cause the oil to stay fluid and impact the Gulf for a longer period of time, St. Pé said.
“As we have emphasized, dispersants are not a silver bullet. They are used to move us toward the lesser of two environmental outcomes,” Lubchenco said. “Until the flow of oil is stemmed, we must take every responsible action to reduce the impact of the oil.”
Dispersants are typically applied on the surface, but the U.S. Environmental Protection Agency approved their underwater use Friday in hopes of combating the leak of millions of gallons of oil from the site of the Deepwater Horizon rig disaster. The rig exploded April 20, killing 11 workers and initiating a massive leak from a well on the sea floor. Workers began injecting the dispersants near the site of the spewing oil in an attempt to limit the amount of crude that reaches the surface.
The chemicals work by breaking the oil into individual droplets that oil-destroying bacteria can break down faster than a solid slick, said Kerry St. Pé, director of the Barataria-Terrebonne National Estuary Program and former head of the state's oil-spill response team. The dispersed oil sinks and moves with the current but is not impacted by surface winds.
Dispersants are toxic, but their use is a trade off and has probably helped keep oil off Louisiana's shore in large volumes, St. Pé said.
“The dispersed oil is probably impacting marine life in the open ocean, and those impacts shouldn't be taken lightly. But those impacts are less than if the oil had come into our estuaries,” St. Pé said.
The presence of giant columns of oil just beneath the surface of the water is unverified by data, Lubchenco said. Scientists aboard the Pelican also found low oxygen levels in the water, but Lubchenco said they were not low enough to be a source of concern. Lubchenco also said there's no evidence to connect the findings and use of underwater dispersants.
“There's no solid scientific evidence that there are these large undersea plumes,” said Charlie Henry, an environmental scientist with NOAA's emergency-response team.
He said scientists were able to find the basic compounds of oil, hydrocarbons, in the water columns, but the data is still being analyzed. In the meantime, NOAA is doing “a number of things to locate oil before it has an adverse impact.” The agency is conducting extensive water sampling and dropping “crab pots” of absorbent material to check for oil under the surface. Researchers are also dropping trawls up to 100 feet underwater to look for oil.
“It will be a long time before we have all the information,” Henry said. “We're looking hard to paint the whole picture, and we're taking a lot of effort and time to analyze and study it.”
He added that the oil on the surface is “the thinnest I've seen yet,” and credited the use of dispersants.
St. Pé said dispersants are the likely reason a relatively small amount of oil has come ashore. He oversaw the application of dispersants to oil spills 20 years ago and said there are strict protocols that must be followed before the chemicals are used.
But he added that applying dispersant near the bottom of the Gulf carries a lot of unknowns.
“It's cold down there, and no one has quantified the impact of those cold temperatures on dispersed oil,” he said, adding that the cold could reduce the breakdown of oil by bacteria, much like a refrigerator keeps food from decaying for longer. That could cause the oil to stay fluid and impact the Gulf for a longer period of time, St. Pé said.
“As we have emphasized, dispersants are not a silver bullet. They are used to move us toward the lesser of two environmental outcomes,” Lubchenco said. “Until the flow of oil is stemmed, we must take every responsible action to reduce the impact of the oil.”
“It will be a long time before we have all the information,” Henry said. “We're looking hard to paint the whole picture, and we're taking a lot of effort and time to analyze and study it.”
He added that the oil on the surface is “the thinnest I've seen yet,” and credited the use of dispersants.
St. Pé said dispersants are the likely reason a relatively small amount of oil has come ashore. He oversaw the application of dispersants to oil spills 20 years ago and said there are strict protocols that must be followed before the chemicals are used.
But he added that applying dispersant near the bottom of the Gulf carries a lot of unknowns.
“It's cold down there, and no one has quantified the impact of those cold temperatures on dispersed oil,” he said, adding that the cold could reduce the breakdown of oil by bacteria, much like a refrigerator keeps food from decaying for longer. That could cause the oil to stay fluid and impact the Gulf for a longer period of time, St. Pé said.
“As we have emphasized, dispersants are not a silver bullet. They are used to move us toward the lesser of two environmental outcomes,” Lubchenco said. “Until the flow of oil is stemmed, we must take every responsible action to reduce the impact of the oil.”
HOUMA — Federal marine scientists said media reports of underwater oil plumes observed by scientists aboard a local research vessel, the Pelican, created an inaccurate picture of vast amounts of crude lurking beneath the surface of the Gulf of Mexico.
Some information “was misleading, premature and, in some cases, inaccurate,” Jane Lubchenco, administrator of the National Oceanic and Atmospheric Administration, said Monday. The scientists aboard the vessel, which is based at the Louisiana Universities Marine Consortium in Cocodrie, were drafted by NOAA to do research on the spill.
Scientists along the Gulf Coast are worried that the unprecedented deep-water use of chemicals called dispersants could be keeping toxic crude below the surface. The New York Times and other news outlets reported that scientists aboard the Pelican found “enormous oil plumes in the deep waters of the Gulf of Mexico, including one as large as 10 miles long, 3 miles wide and 300 feet thick in spots.”
While particles of oil suspended in water were found, federal scientists are still testing how much oil might be underwater and whether dispersants are the cause, Lubchenco said.
More than 560,000 gallons of chemicals have been applied to disperse the oil on the surface and deep in the Gulf. Diffusing and sinking the oil is protecting the coast, scientists say, but could be causing deep-sea impacts. The submerged oil could sink and coat corals and other reef organisms and smother them.
Dispersants are typically applied on the surface, but the U.S. Environmental Protection Agency approved their underwater use Friday in hopes of combating the leak of millions of gallons of oil from the site of the Deepwater Horizon rig disaster. The rig exploded April 20, killing 11 workers and initiating a massive leak from a well on the sea floor. Workers began injecting the dispersants near the site of the spewing oil in an attempt to limit the amount of crude that reaches the surface.
The chemicals work by breaking the oil into individual droplets that oil-destroying bacteria can break down faster than a solid slick, said Kerry St. Pé, director of the Barataria-Terrebonne National Estuary Program and former head of the state's oil-spill response team. The dispersed oil sinks and moves with the current but is not impacted by surface winds.
Dispersants are toxic, but their use is a trade off and has probably helped keep oil off Louisiana's shore in large volumes, St. Pé said.
“The dispersed oil is probably impacting marine life in the open ocean, and those impacts shouldn't be taken lightly. But those impacts are less than if the oil had come into our estuaries,” St. Pé said.
The presence of giant columns of oil just beneath the surface of the water is unverified by data, Lubchenco said. Scientists aboard the Pelican also found low oxygen levels in the water, but Lubchenco said they were not low enough to be a source of concern. Lubchenco also said there's no evidence to connect the findings and use of underwater dispersants.
“There's no solid scientific evidence that there are these large undersea plumes,” said Charlie Henry, an environmental scientist with NOAA's emergency-response team.
He said scientists were able to find the basic compounds of oil, hydrocarbons, in the water columns, but the data is still being analyzed. In the meantime, NOAA is doing “a number of things to locate oil before it has an adverse impact.” The agency is conducting extensive water sampling and dropping “crab pots” of absorbent material to check for oil under the surface. Researchers are also dropping trawls up to 100 feet underwater to look for oil.
“It will be a long time before we have all the information,” Henry said. “We're looking hard to paint the whole picture, and we're taking a lot of effort and time to analyze and study it.”
He added that the oil on the surface is “the thinnest I've seen yet,” and credited the use of dispersants.
St. Pé said dispersants are the likely reason a relatively small amount of oil has come ashore. He oversaw the application of dispersants to oil spills 20 years ago and said there are strict protocols that must be followed before the chemicals are used.
But he added that applying dispersant near the bottom of the Gulf carries a lot of unknowns.
“It's cold down there, and no one has quantified the impact of those cold temperatures on dispersed oil,” he said, adding that the cold could reduce the breakdown of oil by bacteria, much like a refrigerator keeps food from decaying for longer. That could cause the oil to stay fluid and impact the Gulf for a longer period of time, St. Pé said.
“As we have emphasized, dispersants are not a silver bullet. They are used to move us toward the lesser of two environmental outcomes,” Lubchenco said. “Until the flow of oil is stemmed, we must take every responsible action to reduce the impact of the oil.”
Dispersants are typically applied on the surface, but the U.S. Environmental Protection Agency approved their underwater use Friday in hopes of combating the leak of millions of gallons of oil from the site of the Deepwater Horizon rig disaster. The rig exploded April 20, killing 11 workers and initiating a massive leak from a well on the sea floor. Workers began injecting the dispersants near the site of the spewing oil in an attempt to limit the amount of crude that reaches the surface.
The chemicals work by breaking the oil into individual droplets that oil-destroying bacteria can break down faster than a solid slick, said Kerry St. Pé, director of the Barataria-Terrebonne National Estuary Program and former head of the state's oil-spill response team. The dispersed oil sinks and moves with the current but is not impacted by surface winds.
Dispersants are toxic, but their use is a trade off and has probably helped keep oil off Louisiana's shore in large volumes, St. Pé said.
“The dispersed oil is probably impacting marine life in the open ocean, and those impacts shouldn't be taken lightly. But those impacts are less than if the oil had come into our estuaries,” St. Pé said.
The presence of giant columns of oil just beneath the surface of the water is unverified by data, Lubchenco said. Scientists aboard the Pelican also found low oxygen levels in the water, but Lubchenco said they were not low enough to be a source of concern. Lubchenco also said there's no evidence to connect the findings and use of underwater dispersants.
“There's no solid scientific evidence that there are these large undersea plumes,” said Charlie Henry, an environmental scientist with NOAA's emergency-response team.
He said scientists were able to find the basic compounds of oil, hydrocarbons, in the water columns, but the data is still being analyzed. In the meantime, NOAA is doing “a number of things to locate oil before it has an adverse impact.” The agency is conducting extensive water sampling and dropping “crab pots” of absorbent material to check for oil under the surface. Researchers are also dropping trawls up to 100 feet underwater to look for oil.
“It will be a long time before we have all the information,” Henry said. “We're looking hard to paint the whole picture, and we're taking a lot of effort and time to analyze and study it.”
He added that the oil on the surface is “the thinnest I've seen yet,” and credited the use of dispersants.
St. Pé said dispersants are the likely reason a relatively small amount of oil has come ashore. He oversaw the application of dispersants to oil spills 20 years ago and said there are strict protocols that must be followed before the chemicals are used.
But he added that applying dispersant near the bottom of the Gulf carries a lot of unknowns.
“It's cold down there, and no one has quantified the impact of those cold temperatures on dispersed oil,” he said, adding that the cold could reduce the breakdown of oil by bacteria, much like a refrigerator keeps food from decaying for longer. That could cause the oil to stay fluid and impact the Gulf for a longer period of time, St. Pé said.
“As we have emphasized, dispersants are not a silver bullet. They are used to move us toward the lesser of two environmental outcomes,” Lubchenco said. “Until the flow of oil is stemmed, we must take every responsible action to reduce the impact of the oil.”
“It will be a long time before we have all the information,” Henry said. “We're looking hard to paint the whole picture, and we're taking a lot of effort and time to analyze and study it.”
He added that the oil on the surface is “the thinnest I've seen yet,” and credited the use of dispersants.
St. Pé said dispersants are the likely reason a relatively small amount of oil has come ashore. He oversaw the application of dispersants to oil spills 20 years ago and said there are strict protocols that must be followed before the chemicals are used.
But he added that applying dispersant near the bottom of the Gulf carries a lot of unknowns.
“It's cold down there, and no one has quantified the impact of those cold temperatures on dispersed oil,” he said, adding that the cold could reduce the breakdown of oil by bacteria, much like a refrigerator keeps food from decaying for longer. That could cause the oil to stay fluid and impact the Gulf for a longer period of time, St. Pé said.
“As we have emphasized, dispersants are not a silver bullet. They are used to move us toward the lesser of two environmental outcomes,” Lubchenco said. “Until the flow of oil is stemmed, we must take every responsible action to reduce the impact of the oil.”
Sunday, May 16, 2010
Younger generations lack anti-whaling passion: survey
From The Daily Telegraph, Australia:
Younger generations lack anti-whaling passion: survey
AUSTRALIANS remain passionate about ending whaling - with the exception of younger people, a survey shows.
The World Society for the Protection of Animals (WSPA) survey found 94 per cent of people were against whaling in the Southern Ocean.
Yet the same concern was not reflected across all age groups.
Just 35 per cent of respondents aged 18-24 said they cared about the issue, while 55 per cent of the same category were concerned about the killing methods used.
WSPA spokeswoman Louise Fitzsimons says the results are concerning.
"The younger generation does not appear to be getting the message," she said.
"We have no doubt (they) would feel more compelled to speak out against whaling if they were more aware of the extent of cruelty involved when these majestic creatures are hunted and slaughtered."
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The survey of 1274 people aged over 18 also found 61 per cent of respondents were concerned whales were being killed inhumanely.
A federal government proposal demanding closure of the loophole that allows Japan to conduct so-called scientific whaling is supported by almost 90 per cent of respondents, according to the survey.
The proposal, which has been submitted to the International Whaling Commission (IWC), also calls for whaling to be phased out in the Southern Ocean within five years.
WSPA is urging people to join its campaign, Give Whales a Voice.
Campaign ambassador Sami Lukis says decades of progress are threatened by an IWC proposal that could legitimise commercial whaling and end the ban.
"Every Australian can help in the fight," she said, adding that WSPA has scientifically proven there is no humane method of killing a whale at sea.
"The most common way is with a penthrite grenade harpoon, which is designed to explode inside the whale's body," she said.
Younger generations lack anti-whaling passion: survey
AUSTRALIANS remain passionate about ending whaling - with the exception of younger people, a survey shows.
The World Society for the Protection of Animals (WSPA) survey found 94 per cent of people were against whaling in the Southern Ocean.
Yet the same concern was not reflected across all age groups.
Just 35 per cent of respondents aged 18-24 said they cared about the issue, while 55 per cent of the same category were concerned about the killing methods used.
WSPA spokeswoman Louise Fitzsimons says the results are concerning.
"The younger generation does not appear to be getting the message," she said.
"We have no doubt (they) would feel more compelled to speak out against whaling if they were more aware of the extent of cruelty involved when these majestic creatures are hunted and slaughtered."
Start of sidebar. Skip to end of sidebar.
End of sidebar. Return to start of sidebar.
The survey of 1274 people aged over 18 also found 61 per cent of respondents were concerned whales were being killed inhumanely.
A federal government proposal demanding closure of the loophole that allows Japan to conduct so-called scientific whaling is supported by almost 90 per cent of respondents, according to the survey.
The proposal, which has been submitted to the International Whaling Commission (IWC), also calls for whaling to be phased out in the Southern Ocean within five years.
WSPA is urging people to join its campaign, Give Whales a Voice.
Campaign ambassador Sami Lukis says decades of progress are threatened by an IWC proposal that could legitimise commercial whaling and end the ban.
"Every Australian can help in the fight," she said, adding that WSPA has scientifically proven there is no humane method of killing a whale at sea.
"The most common way is with a penthrite grenade harpoon, which is designed to explode inside the whale's body," she said.
Friday, May 14, 2010
Scientists Worried As Invasive 'Tunicate' Appears In Oregon's Coastal Waters; 'Now The Clock Is Ticking'
From Underwater Times: Scientists Worried As Invasive 'Tunicate' Appears In Oregon's Coastal Waters; 'Now The Clock Is Ticking'
CORVALLIS, Oregon -- An aggressive, invasive aquatic organism that is on the state's most dangerous species list has been discovered in both Winchester Bay and Coos Bay, and scientists say this "colonial tunicate" – Didemnum vexillum – has serious economic and environmental implications.
Its propensity to foul surfaces of boats, fishing nets, water intakes, docks and buoys could make it costly to control, and its ability to smother shellfish beds and sensitive marine environments threatens other marine life.
"This is not a welcome addition to our bays and now the clock is ticking," said Sam Chan, an invasive species specialist from Oregon State University and chair of the Oregon Invasive Species Council. "The fouling potential from tunicate invasions can be severe, given its ability to reproduce asexually by budding, or breaking off as fragments, and through sexual reproduction where tadpoles emerge, swim and attach themselves to surfaces to form new colonies.
"Didemnum vexillum was found in Puget Sound several years ago and the expense for treating this invasive species can be quite high," added Chan, who is affiliated with the OSU-based Oregon Sea Grant Extension program. "So it is important to determine how widespread the invasion may be."
A team of scientific divers, coordinated by the Oregon Coast Aquarium, will begin looking in Newport's Yaquina Bay – and perhaps other locations – for colonies of Didemnum vexillum.
The Didemnum invertebrates were first discovered in Winchester Bay, and later in Coos Bay. They are native to Japan and can live from the estuary to the continental shelf. In calm water, colonies may grow in long, beard-like expanses on substrates such as docks, mooring lines, boat hulls and aquaculture infrastructure.
In faster currents, Didemnum forms low, undulating mats overgrowing seabeds of pebbles, boulders and jetty rock. The organisms will grow over, and choke clams, oysters, mussels, anemones and other marine creatures by covering their feeding siphons, and can serve as a barrier between bottom-feeding fish and their prey.
What most concerns scientists, Chan said, is that the tunicates' reproduction cycle begins during the next two months, increasing the chances that colonies will spread. Didemnum is on the list of "100 Worst Invasive Species to Keep out of Oregon."
Between 2007 and 2009, the Washington State Department of Fish and Game spent $850,000 managing the tunicate invasion in Puget Sound, Chan pointed out.
The Winchester Bay tunicate patch was discovered earlier this year by Lorne Curran and Fritz Batson, while Curran was surveying marine life for the organization, REEF. They spotted the organisms in an area called "the triangle" – an enclosed portion of the lower bay shaped like a wedge of pie. Curran photographed the tunicates, and contacted Chan, who then shared the images with tunicate expert Gretchen Lambert, and others, who confirmed the identification.
On April 26, Curran and several divers from the Oregon Coast Aquarium surveyed nearby Salmon Harbor Marina in Winchester Bay to see if the invasion had spread across the bay – and to their relief, it had not. But that relief was short-lived when they returned to the triangle and found that the tunicate colonies appeared to be thriving.
"It appears that the infestation is growing rapidly," Curran said. "Where in February I saw mostly one-foot-square colonies, this time I encountered more colonies that were two-foot to three-foot square." The tunicates were found on both jetty rocks and on some of the mooring lines and "stringers" of an oyster-growing facility in the triangle.
As Chan was working with scientists, community officials and divers on the Winchester Bay discovery, he received word that a second invasion had been discovered by University of Oregon scientist Richard Emlet in the Charleston Boat Basin in Coos Bay. Emlet notified Oregon Department of Fish and Wildlife shellfish biologist Scott Groth, who contacted Chan.
"Based on the size and morphology of both Didemnum vexillum populations, we think they probably became established at roughly the same time – about two years ago," Chan said. "The origin is still unclear and we have to be careful not to point fingers."
Chan said tunicate infestation can be introduced through a variety of vectors, including boats and aquaculture.
The Oregon Department of Fish and Wildlife is in the final stage of a risk assessment. When completed, recommendations will be made and an action plan developed.
"We're reviewing the literature for successful eradication projects on rocky outcrops or jetties, but we're not finding a lot," said Rick Boatner, ODFW's aquatic invasive species coordinator. "This is new ground for Oregon, and we'll have to be creative with our solutions."
Chan and ODFW officials say the best approach may be to establish a pilot "adaptive learning" control and monitoring project within the triangle in early summer before water temperatures warm enough to trigger the tunicates' reproductive cycle. Support for such a project may come through an "Invasive Species Control" fund established by the Oregon Legislature and signed by Gov. Ted Kulongoski in 2009. The Oregon Invasive Species Council must declare an emergency to activate this account, Chan said.
Possible methods of eradication include "smothering" the colonies, physically removing them and vacuuming all traces, or applying a vinegar and/or bleach solution. The Oregon Invasive Species Council will hold workshops in affected coastal communities later this spring to inform the public about tunicates before the pilot control project begins.
Vallorie Hodges, dive safety officer for the Oregon Coast Aquarium, said the Winchester Bay tunicates resembled certain species of soft corals.
"The colonies I observed were all of that cream color and had a sort of undulating soft, lobed or folded appearance in some areas," she said, "while more of a flat mat in others. I saw them not only on the mooring lines (of the oyster facility) but also on the stringers themselves – and on the shellfish."
Despite their invasive nature and ability to "foul" marine structures, tunicates also are being studied as a natural product for unique compounds that may have biomedical applications.
CORVALLIS, Oregon -- An aggressive, invasive aquatic organism that is on the state's most dangerous species list has been discovered in both Winchester Bay and Coos Bay, and scientists say this "colonial tunicate" – Didemnum vexillum – has serious economic and environmental implications.
Its propensity to foul surfaces of boats, fishing nets, water intakes, docks and buoys could make it costly to control, and its ability to smother shellfish beds and sensitive marine environments threatens other marine life.
"This is not a welcome addition to our bays and now the clock is ticking," said Sam Chan, an invasive species specialist from Oregon State University and chair of the Oregon Invasive Species Council. "The fouling potential from tunicate invasions can be severe, given its ability to reproduce asexually by budding, or breaking off as fragments, and through sexual reproduction where tadpoles emerge, swim and attach themselves to surfaces to form new colonies.
"Didemnum vexillum was found in Puget Sound several years ago and the expense for treating this invasive species can be quite high," added Chan, who is affiliated with the OSU-based Oregon Sea Grant Extension program. "So it is important to determine how widespread the invasion may be."
A team of scientific divers, coordinated by the Oregon Coast Aquarium, will begin looking in Newport's Yaquina Bay – and perhaps other locations – for colonies of Didemnum vexillum.
The Didemnum invertebrates were first discovered in Winchester Bay, and later in Coos Bay. They are native to Japan and can live from the estuary to the continental shelf. In calm water, colonies may grow in long, beard-like expanses on substrates such as docks, mooring lines, boat hulls and aquaculture infrastructure.
In faster currents, Didemnum forms low, undulating mats overgrowing seabeds of pebbles, boulders and jetty rock. The organisms will grow over, and choke clams, oysters, mussels, anemones and other marine creatures by covering their feeding siphons, and can serve as a barrier between bottom-feeding fish and their prey.
What most concerns scientists, Chan said, is that the tunicates' reproduction cycle begins during the next two months, increasing the chances that colonies will spread. Didemnum is on the list of "100 Worst Invasive Species to Keep out of Oregon."
Between 2007 and 2009, the Washington State Department of Fish and Game spent $850,000 managing the tunicate invasion in Puget Sound, Chan pointed out.
The Winchester Bay tunicate patch was discovered earlier this year by Lorne Curran and Fritz Batson, while Curran was surveying marine life for the organization, REEF. They spotted the organisms in an area called "the triangle" – an enclosed portion of the lower bay shaped like a wedge of pie. Curran photographed the tunicates, and contacted Chan, who then shared the images with tunicate expert Gretchen Lambert, and others, who confirmed the identification.
On April 26, Curran and several divers from the Oregon Coast Aquarium surveyed nearby Salmon Harbor Marina in Winchester Bay to see if the invasion had spread across the bay – and to their relief, it had not. But that relief was short-lived when they returned to the triangle and found that the tunicate colonies appeared to be thriving.
"It appears that the infestation is growing rapidly," Curran said. "Where in February I saw mostly one-foot-square colonies, this time I encountered more colonies that were two-foot to three-foot square." The tunicates were found on both jetty rocks and on some of the mooring lines and "stringers" of an oyster-growing facility in the triangle.
As Chan was working with scientists, community officials and divers on the Winchester Bay discovery, he received word that a second invasion had been discovered by University of Oregon scientist Richard Emlet in the Charleston Boat Basin in Coos Bay. Emlet notified Oregon Department of Fish and Wildlife shellfish biologist Scott Groth, who contacted Chan.
"Based on the size and morphology of both Didemnum vexillum populations, we think they probably became established at roughly the same time – about two years ago," Chan said. "The origin is still unclear and we have to be careful not to point fingers."
Chan said tunicate infestation can be introduced through a variety of vectors, including boats and aquaculture.
The Oregon Department of Fish and Wildlife is in the final stage of a risk assessment. When completed, recommendations will be made and an action plan developed.
"We're reviewing the literature for successful eradication projects on rocky outcrops or jetties, but we're not finding a lot," said Rick Boatner, ODFW's aquatic invasive species coordinator. "This is new ground for Oregon, and we'll have to be creative with our solutions."
Chan and ODFW officials say the best approach may be to establish a pilot "adaptive learning" control and monitoring project within the triangle in early summer before water temperatures warm enough to trigger the tunicates' reproductive cycle. Support for such a project may come through an "Invasive Species Control" fund established by the Oregon Legislature and signed by Gov. Ted Kulongoski in 2009. The Oregon Invasive Species Council must declare an emergency to activate this account, Chan said.
Possible methods of eradication include "smothering" the colonies, physically removing them and vacuuming all traces, or applying a vinegar and/or bleach solution. The Oregon Invasive Species Council will hold workshops in affected coastal communities later this spring to inform the public about tunicates before the pilot control project begins.
Vallorie Hodges, dive safety officer for the Oregon Coast Aquarium, said the Winchester Bay tunicates resembled certain species of soft corals.
"The colonies I observed were all of that cream color and had a sort of undulating soft, lobed or folded appearance in some areas," she said, "while more of a flat mat in others. I saw them not only on the mooring lines (of the oyster facility) but also on the stringers themselves – and on the shellfish."
Despite their invasive nature and ability to "foul" marine structures, tunicates also are being studied as a natural product for unique compounds that may have biomedical applications.
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