Bacterioplankton distribution and production in deep Pacific waters: Large-scale geographic variations and possible coupling with sinking particle fluxes
Bacterial abundance and leucine incorporation rate were measured throughout the water column (depth, 4,000– 6,000 m) at stations occupied in the equatorial, subtropical, and subarctic Pacific as well as in the Bering Sea during three cruises conducted between 1993 and 1997. In general, depth-depende...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
2000
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| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.513.2174 http://www.aslo.org/lo/toc/vol_45/issue_2/0426.pdf |
| Summary: | Bacterial abundance and leucine incorporation rate were measured throughout the water column (depth, 4,000– 6,000 m) at stations occupied in the equatorial, subtropical, and subarctic Pacific as well as in the Bering Sea during three cruises conducted between 1993 and 1997. In general, depth-dependent decreases of bacterial abundance and leucine incorporation in the bathypelagic layer (depth,.1,000 m) were well described by a power function with remarkably uniform exponents among distant locations: average exponents were 20.900 and 21.33 for abundance and leucine incorporation, respectively. Depth profiles of bacterial properties were complex at some subarctic sta-tions, suggesting lateral transport of organic carbon by local eddies. Organic carbon fluxes from abyssal sediment to overlying water would explain increases in bacterial abundance and leucine incorporation in near-bottom layers. Biomass was twofold to fourfold and the production was threefold to sevenfold greater in subarctic than in sub-tropical regions. This latitudinal pattern was consistent with the basin-scale distribution of sinking fluxes of partic-ulate organic carbon (POC) reported in the literature. Rates of bacterial carbon uptake accounted for 51 % (range, 31–153) and 23 % (14–58) of deep sinking POC fluxes in subarctic and subtropical regions, respectively. Average turnover time of deep bacterial assemblages was estimated to be 1–30 yr. These results suggest that deep bacterial biomass and production are generally coupled with sinking POC fluxes and that organic carbon is substantially |
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