Area and depth of Dead Zones Increasing Steadily
|Rapid biological changes in marine life is attributed to increasing temps and deoxygenation|
It’s not as if there is a shortage of bad news for the planetary ocean: rising temperatures, rising seas, increasing CO2 content, increasing acidification, floating continents of toxic plastics, general pollution, rampant overfishing and mass die-offs. But today’s bad news may be worse in terms of its affect on marine life, and also human life up on the land. According to new research, the oceans have been losing oxygen over the past fifty years and the rate of deoxygenation is accelerating. This process is already causing changes to marine life behavior and reproductive capabilities and none of these changes are good.
According to studies by Scripps Institute, oxygen levels off the coast of California have dropped 20 to 30% over the past 50 years. At the same time, the rapid warming of the planet is reflected directly in ocean temperatures. Warmer water holds less oxygen than cooler water, which accounts for the lower oxygen levels. This has established a positive feedback loop which causes additional global warming: because the warmer water absorbs less CO2, more of it stays in the atmosphere.
While you may have heard of the growing number of dead zones appearing in the Gulf of Mexico and a few hundred other locations around the world, the alarming thing about the new findings is that large deoxygenation zones have been discovered in the open ocean and at surprising depths. Earlier in 2015, scientists at GEOMAR, the Helmholtz Center for Ocean Research Kiel, discovered rotating dead zones in the North Atlantic for the first time.
The accumulated data from around the world supports increasing reports of dying populations of crabs and other commercial seafood, especially in areas off the US West Coast. There is speculation that the mass starfish die-off may also be related to deoxygenation rates.
If ocean oxygen levels continue to drop, it may affect marine life photosynthesis. About half of our atmospheric oxygen – the stuff we breathe – is generated by phytoplankton in the oceans. Not having oxygen to breathe could be disruptive to civilization and cause poor performances on Dancing With The Stars.
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