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| Titel |
Sargasso Sea phosphorus biogeochemistry: an important role for dissolved organic phosphorus (DOP) |
| VerfasserIn |
M. W. Lomas, A. L. Burke, D. A. Lomas, D. W. Bell, C. Shen, S. T. Dyhrman, J. W. Ammerman |
| 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 ; 7, no. 2 ; Nr. 7, no. 2 (2010-02-19), S.695-710 |
| Datensatznummer |
250004497
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| Publikation (Nr.) |
 copernicus.org/bg-7-695-2010.pdf |
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| Zusammenfassung |
| Inorganic phosphorus (SRP) concentrations in the subtropical North Atlantic
are some of the lowest in the global ocean and have been hypothesized to
constrain primary production. Based upon data from several transect cruises
in this region, it has been hypothesized that dissolved organic phosphorus
(DOP) supports a significant fraction of primary production in the
subtropical North Atlantic. In this study, a time-series of phosphorus
biogeochemistry is presented for the Bermuda Atlantic Time-series Study
site, including rates of phosphorus export. Most parameters have a seasonal
pattern, although year-over-year variability in the seasonal pattern is
substantial, likely due to differences in external forcing. Suspended
particulate phosphorus exhibits a seasonal maximum during the spring bloom,
despite the absence of a seasonal peak in SRP. However, DOP concentrations
are at an annual maximum prior to the winter/spring bloom and decline over
the course of the spring bloom while whole community alkaline phosphatase
activities are highest. As a result of DOP bioavailability, the growth of
particles during the spring bloom occurs in Redfield proportions, though
particles exported from the euphotic zone show rapid and significant
remineralization of phosphorus within the first 50 m below the euphotic
zone. Based upon DOP data from transect cruises in this region, the
southward cross gyral flux of DOP is estimated to support ~25% of
annual primary production and ~100% of phosphorus export. These
estimates are consistent with other research in the subtropical North
Atlantic and reinforce the hypothesis that while the subtropics may be
phosphorus stressed (a physiological response to low inorganic phosphorus),
utilization of the DOP pool allows production and accumulation of microbial
biomass at Redfield proportions. |
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