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| Titel |
Physical-Biogeochemical Interactions that Alter the Uptake of Atmospheric CO2 in the Barents Sea |
| VerfasserIn |
S. R. Signorini, S. M. Hakkinen, C. R. McClain |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250024600
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| Zusammenfassung |
| The Barents Sea is characterized by significant calcification rates during summer promoted
by intense coccolithophore blooms that peak during August. Coccolithophores, among which
Emiliania huxleyi (E. huxleyi) is the most abundant and widespread species, are considered to
be the most productive calcifying organisms on Earth. They inhabit the surface layer (MLD
 20m) in highly stratified waters where light intensity is high. E. huxleyi often forms massive
blooms in temperate and sub-polar oceans. Coupling of the coccolithophore organic
carbon and carbonate pumps interact to consume (photosynthesis) and produce
(calcification) CO2. The so-called Rain Ratio, defined as the ratio of particulate
inorganic carbon (PIC) to particulate organic carbon (POC) in exported biogenic
matter, determines the relative strength of the two biological carbon pumps and
influences the flux of CO2 across the surface ocean - atmosphere interface. Here we
use a combination of satellite ocean color algorithms, coupled ice-ocean model
products, an SST-dependent pCO2 algorithm, and gas exchange parameterization to
describe the seasonal and decadal variability of the air-sea CO2 flux in the Barents
Sea. Model-derived SST and SSS (1955-2008) are used in conjunction with the
pCO2 algorithm and carbonate chemistry to derive decadal trends of sea-air CO2
flux, pH and calcite saturation state. Phytoplankton and calcite production have
strong spatial variability. Nutrient supply, biomass and calcite concentrations are
modulated by light and MLD seasonal cycle. The size, intensity, and location of
coccolithophore blooms vary from year to year, but the peak bloom is always in
June in the Central Basin of the sub-polar North Atlantic (45oW - 10oW, 50oN -
65oN) and August in the Barents Sea. Calcification rates range from 5% to 27% of
net primary production. The Barents Sea PIC production is about twice that of
the Central Basin. Predicted freshening and warming of polar seas may increase
stratification, thus favoring an increase in coccolithophore bloom development. |
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