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| Titel |
Dissolved organic matter composition and bioavailability reflect ecosystem productivity in the Western Arctic Ocean |
| VerfasserIn |
Y. Shen, C. G. Fichot, R. Benner |
| 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 ; 9, no. 12 ; Nr. 9, no. 12 (2012-12-06), S.4993-5005 |
| Datensatznummer |
250007452
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| Publikation (Nr.) |
 copernicus.org/bg-9-4993-2012.pdf |
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| Zusammenfassung |
| Dissolved organic carbon (DOC) and total dissolved amino acids (TDAA) were
measured in high (Chukchi Sea) and low (Beaufort Sea) productivity regions
of the western Arctic Ocean to investigate the composition and
bioavailability of dissolved organic matter (DOM). Concentrations and
DOC-normalized yields of TDAA in Chukchi surface waters were relatively
high, indicating an accumulation of bioavailable DOM. High concentrations
and yields of TDAA were also observed in the upper halocline of slope and
basin waters, indicating off-shelf transport of bioavailable DOM from the
Chukchi Sea. In contrast, concentrations and yields of TDAA in Beaufort
surface waters were relatively low, indicting DOM was of limited
bioavailability. Concentrations and yields of TDAA in the upper halocline of
slope and basin waters were also low, suggesting the Beaufort is not a major
source of bioavailable DOM to slope and basin waters. In shelf waters of
both systems, elevated concentrations and yields of TDAA were often observed
in waters with higher chlorophyll concentrations and productivity. Surface
concentrations of DOC were similar (p > 0.05) in the two systems
despite the contrasting productivity, but concentrations and yields of TDAA
were significantly higher (p < 0.0001) in the Chukchi than in the
Beaufort. Unlike bulk DOC, TDAA concentrations and yields reflect ecosystem
productivity in the western Arctic. The occurrence of elevated bioavailable
DOM concentrations in the Chukchi Sea implies an uncoupling between the
biological production and utilization of DOM and has important implications
for sustaining heterotrophic microbial growth and diversity in oligotrophic
waters of the central Arctic basins. |
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