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hatrack

(59,587 posts)
Thu Apr 28, 2016, 10:25 PM Apr 2016

NCAR Study- Oxygen Depletion In Planet's Oceans Will Be Widespread by 2030s

EDIT

The damage caused by ocean oxygen loss is multi-variant and wide-ranging. The most obvious harm comes in the form of generating environments in which oxygen-dependent life in the oceans can no longer breathe. Any living creature that filters oxygen out of the water for respiration falls under threat due to lowered ocean oxygen levels. A group that includes pretty much all the advanced, multi-cellular life in the seas. A press statement from the new NCAR study notes: Scientists know that a warming climate can be expected to gradually sap the ocean of oxygen, leaving fish, crabs, squid, sea stars, and other marine life struggling to breathe.

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Hydrogen sulfide producing bacteria blooms off the coast of Namibia during 2007. Hydrogen sulfide is a highly toxic gas. One that is produced by microbes that live in waters containing little or no oxygen. Image source: Earth Observatory.

But a second, less immediately obvious hit comes in the form of generating expanding anoxic environments that favor the proliferation of toxin-producing microbes. Called dead zones, these oxygen-poor regions not only provide a suffocation threat to sea life, but they also form areas of water in which environmental toxins can build up. The result is a long-lasting negative impact to the health of life in the ocean and, in the most extreme cases, on land and in the airs as well. The worst of these toxin-generating microbes are the hydrogen-sulfide producing bacteria. An ancient organism that is incompatible with oxygen-dependent life. A horror out of deep time that has tended to crop up again and again on the list of usual suspects of major hothouse extinction killers. A likely perpetrator of the big ocean and land die offs during pretty much all global warming based extinctions. An organism that dominated the world’s seas and likely vented its deadly gasses into the airs of the world of the Permian — during the worst die-off Earth has ever seen.

EDIT

In the NCAR study, which is well worth reading in full, scientists used model runs to determine when and where climate change would start to deprive the world ocean system of oxygen. The study found that regions off the coast of West Africa, regions west of South America, an area to the west of Australia, and a section of the Beaufort Sea were already experiencing lower levels of ocean oxygen due to global warming. West African seas were the first and hardest hit by warming in the models. This is interesting due to the fact that Namibia on the West Coast of Africa is one of the only regions of the world now observed to experience blooms of hydrogen sulfide producing bacteria that extend into the surface waters. West African waters have also generated a number of mobile, low-oxygen dead zones that have spiraled on off into the North Atlantic.

The fact that the NCAR study indicates that global warming has already reduced ocean oxygen levels in a region that is producing both dead zones and, in the case of Nambia, periods during which hydrogen sulfide producing bacteria appear at the surface, is cause for some concern. For by the 2030s, the NCAR model study indicates that global warming will be actively reducing ocean oxygen levels across the vast majority of the North Pacific, a majority of the South Pacific, most of the South Atlantic, and pretty much all of the Indian Ocean region covered in the new research. This raises the risk that open water dead zones like the ones seen off Africa and even hydrogen sulfide producing hot spots like Nambia may begin to creep into other regions of the world ocean — generating further threats to sea life, to fishing industry, and to human beings who depend on healthy oceans for livelihood and for life.

EDIT

https://robertscribbler.com/

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NCAR Study- Oxygen Depletion In Planet's Oceans Will Be Widespread by 2030s (Original Post) hatrack Apr 2016 OP
Cough cough....Canfield Oceans.....cough cough NickB79 May 2016 #1
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