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| Titel |
Climate change and ocean acidification impacts on lower trophic levels and the export of organic carbon to the deep ocean |
| VerfasserIn |
A. Yool, E. E. Popova, A. C. Coward, D. Bernie, 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 ; 10, no. 9 ; Nr. 10, no. 9 (2013-09-05), S.5831-5854 |
| Datensatznummer |
250085322
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| Publikation (Nr.) |
 copernicus.org/bg-10-5831-2013.pdf |
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| Zusammenfassung |
| Most future projections forecast significant and ongoing climate change
during the 21st century, but with the severity of impacts dependent on
efforts to restrain or reorganise human activity to limit carbon dioxide
(CO2) emissions. A major sink for atmospheric CO2, and a key source of
biological resources, the World Ocean is widely anticipated to undergo
profound physical and – via ocean acidification – chemical changes as
direct and indirect results of these emissions. Given strong biophysical
coupling, the marine biota is also expected to experience strong changes in
response to this anthropogenic forcing. Here we examine the large-scale
response of ocean biogeochemistry to climate and acidification impacts during
the 21st century for Representative Concentration Pathways (RCPs) 2.6 and 8.5
using an intermediate complexity global ecosystem model, MEDUSA-2.0. The
primary impact of future change lies in stratification-led declines in the
availability of key nutrients in surface waters, which in turn leads to a
global decrease (1990s vs. 2090s) in ocean productivity (−6.3%). This
impact has knock-on consequences for the abundance of the low trophic level
biogeochemical actors modelled by MEDUSA-2.0 (−5.8%), and these would
be expected to similarly impact higher trophic level elements such as
fisheries. Related impacts are found in the flux of organic material to
seafloor communities (−40.7% at 1000 m), and in the volume of ocean
suboxic zones (+12.5%). A sensitivity analysis removing an acidification
feedback on calcification finds that change in this process significantly
impacts benthic communities, suggesting that a~better understanding of the
OA-sensitivity of calcifying organisms, and their role in ballasting sinking
organic carbon, may significantly improve forecasting of these ecosystems.
For all processes, there is geographical variability in change – for
instance, productivity declines −21% in the Atlantic and increases
+59% in the Arctic – and changes are much more pronounced under RCP 8.5
than the RCP 2.6 scenario. |
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