Researchers have detected a decline in the amount of oxygen dissolved in the world’s oceans. The research was published in the journal Nature by oceanographer Sunke Schmidtko at the Geomar Center for Ocean Research in Kiel, Germany. Schmidtko and his colleagues found that from 1960 to 2010 there was a decline of more than 2 percent in ocean oxygen. Although the loss appeared worldwide, it was more pronounced in some ocean areas. The sharpest decline was seen in the Arctic Ocean, a region already faced with dramatic consequences of climate change. Read our post: 2016 The Hottest Year in Recorded History and: The Year the World Focused on Climate Change (photo – surf session.com)
Ocean Oxygen Loss Occurring on a Global Scale
The loss of oxygen had been predicted to occur based on models, and there has been evidence of regional declines but this was the first research showing ocean oxygen loss on a global scale and in the deep ocean.
Oxygen dissolves in the ocean at its surface, directly from the atmosphere or indirectly thru photosynthesis in marine microorganisms. Climate change effects this ocean oxygen in several ways; primarily, warmer water holds less dissolved oxygen. But also as the upper layer of oxygen-rich waters warm and become less dense, it becomes less likely to sink and mix with the deeper, cooler layers of the ocean. It is thought that less than 15% of the oxygen loss was due directly to warmer temperatures, the remainder seems to be a result of not mixing with deeper ocean layers. (photo – Earth.com)
The Consequences of Global Warming
This new research underscores that many of the most profound consequences of global warming are occurring in the sea, not on land. Read our new post Ocean Warming Faster: New Research Shows. (map – World Resource Institute)
The results are clear to see including massive coral reef bleaching events, like that occurring in the Great Barrier Reef, see: Can the Great Barrier Reef be Saved. Die-offs in kelp forests; the melting of glaciers in Greenland and Antarctica and the ocean’s “dead zones” increasing in size. And this may be just the beginning, studies suggest that a loss of 7% of the ocean’s oxygen might happen by 2100. “With far-reaching implications for marine ecosystems and fisheries to be expected.” Read our post: Marine Migrations Magnified by Ocean Warming. (photo – Burt Jones, Maureen Shimlock)
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