'DEAD ZONE'

from : http://spectregroup.wordpress.com/2010/07/01/dead-zone/


concentrations of algal blooms that contribute to dead zones / photo: NASA

as in : ‘How Big is the Dead Zone this Year?’
http://reuters.com/article/idUSTRE65L6IA20100622
http://bizjournals.com/houston/stories/2010/06/28/daily24.html
“The 2010 forecast released by NOAA predicts that the dead zone could measure between 6,500 and 7,800 square miles, equivalent to the size of Lake Ontario. The Gulf dead zone forms each spring and summer off the Louisiana and Texas coasts when oxygen levels drop too low to support most life in bottom and near-bottom waters. Farmland runoff containing fertilizers and livestock waste is the main source of the nitrogen and phosphorus that fuel the growth of algae blooms, that in turn create the dead zone. The five largest Gulf dead zones on record have occurred since 2001. The biggest occurred in 2002 and measured 8,484 square miles. The official size of the 2010 Gulf dead zone will be announced following a NOAA-supported monitoring survey led by the Louisiana Universities Marine Consortium being held from July 24 through Aug. 2.”

Hypoxia
http://ncddc.noaa.gov/activities/gulf-hypoxia-stakeholders
http://livescience.com/environment/080814-oceans-oxygen.html
“A review of research into these so-called “dead zones,” in the journal Science, finds that the number of dead zones has roughly doubled every decade since the 1960’s. The study authors tallied 405 dead zones in coastal waters worldwide today, affecting about 95,000 square miles (245,000 square kilometers) of ocean.”

Massive Methane Bubble Caused Explosion
http://guardian.co.uk/environment/2010/may/08/deepwater-horizon-blast-methane-bubble
http://guardian.co.uk/environment/2010/jun/30/biologists-find-oil-spill-deadzones
“A report into last month’s blast said the gas escaped from the oil well and shot up the drill column, expanding quickly as it burst through several seals and barriers before exploding. Now scientists are confronting growing evidence that BP’s ruptured well is expanding oxygen-depleted “dead zones” where fish and other marine life cannot survive. In two separate research voyages, independent scientists have detected what were described as “astonishingly high” levels of methane, or natural gas, bubbling from the well site, setting off a chain of reactions that suck the oxygen out of the water. In some cases, methane concentrations are 100,000 times normal levels. The finding presents a new challenge to scientists who so far have been focused on studying the effects on the Gulf of crude oil, and the 5.7m litres of chemical dispersants used to break up the slick. Such high concentrations, it is feared, would trigger the growth of microbes, which break up the methane, but also gobble up oxygen needed by marine life to survive, driving out other living things. Joye said the methane was settling in a 200-metre layer of the water column, between depths of 1,000 to 1,300 metres in concentrations that were already threatening oxygen levels. A Texas A&M University oceanographer issued a similar warning last week on his return from a 10-day research voyage in the Gulf. John Kessler recorded “astonishingly high” methane levels in surface and deep water within a five-mile radius of the ruptured well. His team also recorded 30% depletion of oxygen in some locations.”

Pollution vs Pollution : Add More Fertilizer?
http://newscientist.com/article/dn18971-bacteria-help-to-clean-up-deepwater-horizon-spill.html
“Over the past few years, researchers have found that dozens of different kinds of marine bacteria have a healthy appetite for oil. Water samples from the Gulf of Mexico are showing signs that marine bacteria are already pitching in to help with clean-up efforts, and that populations of these bacteria in this area are likely to boom as they feast on the oil from the Deepwater Horizon disaster. Crucially, R/V Pelican happened to be in the area when Deepwater Horizon blew up. That means the team could immediately collect water samples to test for bacterial populations from areas that were threatened by the spill but had not yet been contaminated. “Now we plan to see how the microbial community evolves when you give it oil,” says Grimes. He hopes to screen bacteria from oil-affected water for the DNA of oil-eating enzymes, and use this to determine their species. In previous research he found that Vibrio became the dominant type of marine bacteria off the south-eastern US as oil tanker traffic increased after the 1970s. Atlas, who managed the “bioremediation” of the 1989 Exxon Valdez spill in Alaska, says the bacterial process will be helped if fertilizer is added to the water, as then the oil-eaters will have the nitrogen and phosphate they need to grow. Fertilizer has already been used to aid the bacterial breakdown of oil that has hit the shore, but it could also help bacteria in the open sea if it is added to the detergents that are being used to disperse the oil. The fertilizer lodges in the surface of the oil droplets created by the detergents, he says – right where the bacteria can use them.”


Chemosynthetic Community Locations in the Gulf of Mexico

Oil Eaters (This Has Come Up Before)
http://www.gomr.mms.gov/homepg/regulate/environ/chemo/chemo.html
http://www.nytimes.com/slideshow/2010/06/22/science/20100622cold.html
http://www.nytimes.com/2010/06/22/science/22cool.html
“The deep seabed was once considered a biological desert. Life, the logic went, was synonymous with light and photosynthesis. The sun powered the planet’s food chains, and only a few scavengers could ply the preternaturally dark abyss. Then, in 1977, oceanographers working in the deep Pacific stumbled on bizarre ecosystems lush with clams, mussels and big tube worms — a cornucopia of abyssal life built on microbes that thrived in hot, mineral-rich waters welling up from volcanic cracks, feeding on the chemicals that leached into the seawater and serving as the basis for whole chains of life that got along just fine without sunlight. In 1984, scientists found that the heat was not necessary. In exploring the depths of the Gulf of Mexico, they discovered sunless habitats powered by a new form of nourishment. The microbes that founded the food chain lived not on hot minerals but on cold petrochemicals seeping up from the icy seabed. Today, scientists have identified roughly one hundred sites in the gulf where cold-seep communities of clams, mussels and tube worms flourish in the sunless depths. And they have accumulated evidence of many more — hundreds by some estimates, thousands by others — most especially in the gulf’s deep, unexplored waters. “It wouldn’t surprise me if there were 2,000 communities, from suburbs to cities,” said Ian R. MacDonald, an oceanographer at Florida State University who studies the dark ecosystems. The world’s richest known concentration of these remarkable communities is in the Gulf of Mexico. The life forms include tube worms up to eight feet long. Some of the creatures appear old enough, scientists say, to predate the arrival of Columbus in the New World. Now, by horrific accident, these cold communities have become the subject of a quiet debate among scientists. The gulf is, of course, the site of the giant oil spill that began April 20 with the explosion of the Deepwater Horizon drill rig. The question is what the oil pouring into the gulf means for these deep, dark habitats, in contrast to the slow, diffuse, chronic seepage of petrochemicals across much of the gulf’s northern slope. Many factors, like the density of oil in undersea plumes, the size of resulting oxygen drops and the potential toxicity of oil dispersants — all unknowns — could grow into threats that outweigh any possible benefits and damage or even destroy the dark ecosystems.”

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