Deoxigenation

Climate change has caused reduction in the amount of oxygen dissolved in oceans worldwide, according to a new study led by the National Center for Atmospheric Research (NCAR). The change is already evident in some parts and will be apparent across large regions of the oceans between 2030 and 2040.

Scientists say that a warming climate can deplete the ocean of oxygen, leaving fish, crabs, squid, sea stars, and other marine life struggling to breathe. But it's been difficult to determine whether this anticipated oxygen drain is already having a noticeable impact.

"Loss of oxygen in the ocean is one of the serious side effects of a warming atmosphere, and a major threat to marine life," said NCAR scientist Matthew Long, lead author of the study. “Since oxygen concentrations in the ocean depend on variations in winds and temperature at the surface, it's been challenging to attribute any deoxygenation to climate change. This new study tells us when we can expect the impact from climate change to overwhelm the natural variability."

The study is published in the journal Global Biogeochemical Cycles, a publication of the American Geophysical Union.

The research team found that deoxygenation caused by climate change could already be detected in the southern Indian Ocean and parts of the eastern tropical Pacific and Atlantic basins. They also determined that more widespread detection of deoxygenation caused by climate change would be possible between 2030 and 2040. However, in some parts of the ocean, including areas off the east coasts of Africa, Australia, and Southeast Asia, deoxygenation caused by climate change was not evident even by 2100.

Downtoearth

Deoxigenation due to climate change is already detectable in some parts of the ocean. New research from NCAR finds that it will likely become widespread between 2030 and 2040. Other parts of the ocean, shown in gray, will not have detectable loss of oxygen due to climate change even by 2100. Credit: Matthew Long, NCAR.

Read more at: https://phys.org/news/2016-04-widespread-loss-ocean-oxygen-2030s.html#jCp