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Ocean acidification corrodes the shells of marine microorganisms. Pteropods, to the right, are  among those species that are particularly vulnerable to this. Photo: Matt Wilson/Jay Clark, NOAA NMFS AFSC.

Southern Ocean acidification creates shallower horizon for marine organisms

The living conditions for marine microorganisms in the Southern Ocean may dramatically worsen by the end of the century. More acidic water can make their territories shallower.

This is shown in a new modeling study published in the journal Nature Climate Change. With a business as usual CO2 emission scenario, the authors found that the boundary where the shells of calcifying organisms start to corrode, is raised from around a thousand meters' depth to less than a hundred. 

Microorganisms with calcium carbonate shells will not have time to adjust to the changing conditions. The results from the climate model indicate that such changes can occur as quickly as from one year to the next. This may affect the marine ecosystems significantly.

"In the worst case, such abrupt changes may indirectly affect fisheries", says Siv Lauvset at the Bjerknes Centre for Climate Research, NORCE and the Geophysical Institute at the University of Bergen. 

She is one of the researchers behind the study, led from the University of Colorado Boulder. 

Read more about the study here.  

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Pteropods are particularly vulnerable to ocean acidification. Artistic rendering by Kristen Krumhardt, one of the researchers behind the study.

 

Reference

Gabriela Negrete-García, Nicole S. Lovenduski, Claudine Hauri, Kristen M. Krumhardt & Siv K. Lauvset: Sudden emergence of a shallow aragonite saturation horizon in the Southern Ocean. Nature Climate Change (2019)