Mechanisms for Variation of Cellular P Stoichiometry: Diverse Cellular Phosphorus Allocation Strategies Across Microbial Groups from the Sargasso Sea
Abstract
Phosphorus is the least abundant of the three major macronutrients that define the canonical Redfield ratio, but its place in the backbone of nucleic acids and as an energy trafficking molecule lays a lower bound of cellular phosphorus content that is essential for all life. In addition to forming DNA, RNA, and adenosine triphosphate (ATP), significant amounts of cellular phosphorus may also be allocated to the production of phospholipids and polyphosphate. These latter two biochemicals in particular may occur in significant but highly variable amounts across different microbial groups, and the variation in cellular allocation to these biochemicals may be a contributing factor in defining the elemental stoichiometry of microbes. We investigated this variation in cellular phosphorus allocation across the most abundant microbial groups in the P-depleted Sargasso Sea: Prochlorococcus, Synechococcus, and heterotrophic bacteria. By coupling radioisotope tracing of phosphate and ATP with cell sorting flow cytometry and subsequent biochemical extractions, we made novel measurements of the P allocation to DNA, phospholipids, and polyphosphate in individual microbial groups from environmental populations. These results provide new insights into the cellular mechanisms of variation in stoichiometry and different microbial strategies for adaptation to low-P environments.
- Publication:
-
American Geophysical Union, Ocean Sciences Meeting
- Pub Date:
- February 2016
- Bibcode:
- 2016AGUOS.B52A..03P
- Keywords:
-
- 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGEDE: 1635 Oceans;
- GLOBAL CHANGEDE: 4845 Nutrients and nutrient cycling;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICALDE: 4855 Phytoplankton;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL