Seston effects on faecal pellet carbon concentrations from a mixed community of copepods in Balsfjord, Norway, and the Antarctic Polar Front

Abstract

The effects of phytoplankton community composition on faecal pellet carbon concentrations from a mixed community of large (>500 m) copepods were examined in studies in two areas: Balsfjord, Norway, and the Pacific sector of the Antarctic Polar Front. The Balsfjord study was conducted during the spring bloom of 1994. Faecal pellet production rates, dry weights and total amino acid carbon concentrations were positively correlated with chlorophyll concentrations. However, faecal pellet carbon concentrations were not correlated to chlorophyll levels but rather appeared related to the phytoplankton community composition. Lower faecal pellet carbon concentrations were consistently found when diatoms constituted >50% of the available plankton. Similar results were found in the Antarctic Polar Front study, which was conducted during the austral spring and summer of 1997–1998. Over spring and summer, faecal pellet carbon concentrations were negatively correlated with particulate biogenic silica concentrations. Results from both of these field studies suggest that, on a community level, the diet of copepods affects the carbon concentration of the pellets and thus the potential flux of carbon via faecal pellets. 2001 International Council for the Exploration of the Sea