Calculus of P-Acquisition versus P-Sparing by Plankton in the Oligotrophic Ocean (Invited)
Abstract
Phosphate concentrations in the Sargasso Sea are among the lowest observed in the open oceans; at times concentrations can become sub-nanomolar. It has been suggested that the scarcity of phosphate in this region plays a key role in limiting rates of primary production, bacterial respiration, and nitrogen fixation. The myriad physiological responses of plankton to phosphate scarcity fall into two basic categories: 1) expending energy and resources in an attempt to acquire P from dissolved organic matter, or 2) adjusting the biochemical composition of the cell in an attempt to spare P and continue to grow with less P. In theory, these two types of responses should have opposing impacts on the partitioning of P between the particulate and dissolved pools. In a transect across the north-western boundary of the Sargasso Sea, we measured examples of these two types of responses: rates of alkaline phosphatase activity and relative abundance of non-phosphorus membrane lipids. Although, both parameters generally increased with decreasing phosphate concentrations, there were distinct differences in theses responses. Analysis of these differences has provided key insights on the calculus of P-acquisition vs. P-sparing by members of the planktonic community.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.B33K..04V
- Keywords:
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- 0470 BIOGEOSCIENCES / Nutrients and nutrient cycling;
- 4825 OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL / Geochemistry;
- 4840 OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL / Microbiology and microbial ecology;
- 4850 OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL / Marine organic chemistry