Abstract
The smallest phototrophic protists (<3 μm) are important primary producers in oligotrophic subtropical gyres - the Earth's largest ecosystems. In order to elucidate how these protists meet their inorganic nutrient requirements, we compared the phosphate uptake rates of plastidic and aplastidic protists in the phosphate-depleted subtropical and tropical North Atlantic (4-29°N) using a combination of radiotracers and flow cytometric sorting on two Atlantic Meridional Transect cruises. Plastidic protists were divided into two groups according to their size (<2 and 2-3 μm). Both groups of plastidic protists showed higher phosphate uptake rates per cell than the aplastidic protists. Although the phosphate uptake rates of protist cells were on average seven times (P<0.001) higher than those of bacterioplankton, the biomass-specific phosphate uptake rates of protists were one fourth to one twentieth of an average bacterioplankton cell. The unsustainably low biomass-specific phosphate uptake by both plastidic and aplastidic protists suggests the existence of a common alternative means of phosphorus acquisition - predation on phosphorus-rich bacterioplankton cells.
Original language | English |
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Pages (from-to) | 327-335 |
Number of pages | 0 |
Journal | FEMS Microbiol Ecol |
Volume | 78 |
Issue number | 2 |
DOIs | |
Publication status | Published - Nov 2011 |
Keywords
- Atlantic Ocean
- Biomass
- Ecological and Environmental Phenomena
- Ecosystem
- Eukaryota
- Flow Cytometry
- Phosphates
- Seawater
- Water Pollutants
- Chemical