Protist Community Grazing on Prokaryotic Prey in Deep Ocean Water Masses

PLoS One. 2015 Apr 20;10(4):e0124505. doi: 10.1371/journal.pone.0124505. eCollection 2015.

Abstract

Oceanic protist grazing at mesopelagic and bathypelagic depths, and their subsequent effects on trophic links between eukaryotes and prokaryotes, are not well constrained. Recent studies show evidence of higher than expected grazing activity by protists down to mesopelagic depths. This study provides the first exploration of protist grazing in the bathypelagic North Atlantic Deep Water (NADW). Grazing was measured throughout the water column at three stations in the South Atlantic using fluorescently-labeled prey analogues. Grazing in the deep Antarctic Intermediate water (AAIW) and NADW at all three stations removed 3.79% ± 1.72% to 31.14% ± 8.24% of the standing prokaryote stock. These results imply that protist grazing may be a significant source of labile organic carbon at certain meso- and bathypelagic depths.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Antarctic Regions
  • Chlorophyll / chemistry
  • Eukaryota / metabolism*
  • Fluorescent Dyes / chemistry
  • Food Chain*
  • Geography
  • In Situ Hybridization, Fluorescence
  • Light
  • Microscopy, Fluorescence
  • Oceans and Seas*
  • Oxygen / chemistry
  • Phenothiazines
  • Prokaryotic Cells*
  • Seawater
  • Temperature

Substances

  • Fluorescent Dyes
  • Phenothiazines
  • Chlorophyll
  • protizinic acid
  • Oxygen

Grants and funding

Funding for the cruise was provided by the National Science Foundation (OCE-1154320) to EBK. Funding for the laboratory work was provided by contributions from the Woods Hole Oceanographic Institution Director of Research, Ocean Life Institute, and Deep Ocean Exploration Institute to VE. No individuals employed or contracted by the funders played any role in this study.