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| Titel |
Regional variability of acidification in the Arctic: a sea of contrasts |
| VerfasserIn |
E. E. Popova, A. Yool, Y. Aksenov, A. C. Coward, T. R. Anderson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 2 ; Nr. 11, no. 2 (2014-01-23), S.293-308 |
| Datensatznummer |
250117143
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| Publikation (Nr.) |
 copernicus.org/bg-11-293-2014.pdf |
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| Zusammenfassung |
| The Arctic Ocean is a region that is particularly vulnerable to the
impact of ocean acidification driven by rising atmospheric CO2, with potentially
negative consequences for calcifying organisms such as coccolithophorids
and foraminiferans. In this study, we use an ocean-only general
circulation model, with embedded biogeochemistry and a comprehensive
description of the ocean carbon cycle, to study the response of pH and
saturation states of calcite and aragonite to rising atmospheric pCO2 and changing climate in
the Arctic Ocean. Particular attention is paid to the strong
regional variability within the Arctic, and, for comparison,
simulation results are contrasted with those for the global
ocean. Simulations were run to year 2099 using the RCP8.5 (an Intergovernmental
Panel on Climate Change (IPCC) Fifth Assessment Report (AR5)
scenario with the highest concentrations of atmospheric CO2). The separate impacts of
the direct increase in atmospheric CO2 and indirect effects via
impact of climate change (changing temperature, stratification, primary
production and freshwater fluxes) were examined by undertaking two
simulations, one with the full system and the other in which
atmospheric CO2 was prevented from increasing
beyond its preindustrial level (year 1860). Results indicate that
the impact of climate change, and spatial heterogeneity thereof, plays a strong
role in the declines in pH and carbonate saturation (Ω) seen in
the Arctic. The central Arctic, Canadian Arctic Archipelago and
Baffin Bay show greatest rates of acidification and Ω decline as
a result of melting sea ice. In contrast, areas affected by Atlantic
inflow including the Greenland Sea and outer shelves of the Barents,
Kara and Laptev seas, had minimal decreases in pH and Ω because
diminishing ice cover led
to greater vertical mixing and primary production. As a consequence, the
projected onset of undersaturation in respect to aragonite is highly variable regionally
within the Arctic, occurring during the decade of 2000–2010 in the
Siberian shelves and Canadian Arctic Archipelago, but as late as the
2080s in the Barents and Norwegian seas.
We conclude that, for future projections of acidification and carbonate
saturation state in the Arctic, regional variability is significant
and needs to be adequately resolved, with particular emphasis on reliable projections of the
rates of retreat of the sea ice, which are a major source of
uncertainty. |
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