A new study shows that rising sea temperatures worldwide negatively affects the levels of dissolved oxygen in our planet’s oceans. Scientists found that the phenomenon will be obvious in all world’s oceans by 2030 to 2040 if climate change is left unchecked.
Curtis Deutsch, lead author of the study and researcher at the University of Washington’s School of Oceanography, explained that as global sea temperatures go up, marine oxygen levels will go down. Yet, Deutsch acknowledged that at the moment it is rather hard to assess climate-driven changes in the oceans.
Deutsch’s team comprised of researchers from the Georgia Institute of Technology and National Center for Atmospheric Research used a modeling approach in their research. They resorted to computing power to map out all the changes brought to oxygen levels in oceans by climate change through the end of the century.
The models revealed that it is impossible to tell climate-driven changes in oxygen levels from those caused by other sources such as fertilizer pollution and acidification.
The study showed that in the southern parts of the Indian Ocean and the eastern tropical region of the Pacific and Atlantic Oceans climate-related oxygen loss is already evident. Other areas won’t experience any changes sooner than 2100.
The study results were published in the journal Global Biogeochemical Cycles.
Deutsch noted that in some oceans changes are visible relatively early, but in other regions deoxygenation is hard to detect due to natural variation and the slow pace of depletion.
Researchers noticed that climate change-linked oxygen depletion was obvious in regions marked by extreme deoxygenation or long-lasting low oxygen levels. Deutsch added that the southern Indian Ocean, which has seen some of the longest trends of warming in recent years, will be the worst hit by recurrent oxygen loss incidents.
The research team explained that oxygen levels shape the areas where fish and other marine life can live or not. According to the study, for each extra degree of sea warming, oxygen levels will slip two percent.
Another effect of higher ocean temperatures is a slower ocean circulation on the short run, which will further fuel oxygen loss. Warming will also widen the gap between oxygen-rich ocean layers (from the surface) and those depleted of oxygen (from the deeper ocean), preventing them from mixing with one another to reach an equilibrium.
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