Arctic Ocean acidification worse than previously expected

Date:
June 17, 2020
Source:
University of Bern
Summary:
The Arctic Ocean will take up more carbon dioxide over the 21st
century than predicted by most climate models, according to
researchers. This additional carbon dioxide causes a distinctly
stronger ocean acidification.



FULL STORY ==========================================================================
The Arctic Ocean will take up more CO2 over the 21st century than
predicted by most climate models. This additional CO2 causes a
distinctly stronger ocean acidification. These results were published
in a study by climate scientists from the University of Bern and E'cole
normale supe'rieure in Paris. Ocean acidification threatens the life
of calcifying organisms -- such as mussels and "sea butterflies" --
and can have serious consequences for the entire food chain.


==========================================================================
The ocean takes up large amounts of human-made CO2 from the
atmosphere. This additional CO2 causes ocean acidification, a process
that can already be observed today. Ocean acidification particularly
impacts organisms that form calcium carbonate skeletons and shells,
such as molluscs, sea urchins, starfish and corals. The Arctic Ocean is
where acidification is expected to be greatest.

A study that was recently published in the scientific journal Nature by
Jens Terhaar from Bern and Lester Kwiatkowski and Laurent Bopp from the
E'cole normale supe'rieure in Paris shows, that ocean acidification in
the Arctic Ocean is likely to be even worse than previously thought. The results show that the smallest of the seven seas will take up 20% more
CO2 over the 21st century than previously expected, under the assumption
that the atmospheric CO2 concentrations continue to increase. "This leads
to substantially enhanced ocean acidification, particularly between
200 and 1000 meters," explains Jens Terhaar, member of the group for
ocean modeling at the Oeschger-Centre for Climate Change Research at
the University of Bern. This depth range is an important refuge area
for many marine organisms.

Consequences for the food chain Ocean acidification negatively impacts organisms that build calcium carbonate skeletons and shells. In
sufficiently acidic waters, these shells become unstable and begin to
dissolve. "Our results suggest that it will be more difficult for Arctic organisms to adapt to ocean acidification than previously expected,"
says co-author Lester Kwiatkowski. A loss of these organisms is likely
to impact the entire Arctic food chain up to fish and marine mammals.

New method improves projections The international research team exploited
the large divergence in simulated Arctic Ocean carbon uptake by current
climate models. The researchers found a physical relationship across
the models between the simulation of present-day Arctic sea surface
densities and associated deep-water formation, with greater deep-water formation causing enhanced transport of carbon into the ocean interior
and therefore enhanced acidification. Using measurements of Arctic sea
surface density the research team was able to correct for biases in the
models and reduce the uncertainty associated with projections of future
Arctic Ocean acidification.


========================================================================== Story Source: Materials provided by University_of_Bern. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Jens Terhaar, Lester Kwiatkowski, Laurent Bopp. Emergent
constraint on
Arctic Ocean acidification in the twenty-first century. Nature,
2020; 582 (7812): 379 DOI: 10.1038/s41586-020-2360-3 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200617145947.htm

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