Plankton community structure and carbon cycling on the western coast of Greenland during the stratified summer situation. II. Heterotrophic dinoflagellates and ciliates

The trophic role of marine pelagic ciliates and heterotrophic dinoflagellates in arctic and temperate coastal ecosystems: A cross‐latitude comparison

“…Physicochemical measurements-Vertical profiling of temperature, salinity and chlorophyll fluorescence was conducted as described in Kiørboe and Nielsen (1994) and Levinsen et al (2000a). Solar irradiance was calculated as photosynthetically active radiation (PAR) from total global irradiance measured at Qeqertarsuaq by the Arctic Station of the University of Copenhagen (Disko Bay) or at Nakkehoved by the Danish Meteorological Institute (Kattegat).…”

“…Primary producers-Chlorophyll a (Chl a) was measured following extractions in 96% ethanol (Disko Bay; Levinsen et al 2000a) or 90% acetone (Kattegat; Richardson and Christoffersen 1991).…”

“…When assuming complete algivory, 32-55% and 20-60% of the annual primary production was consumed by ciliates in Disko Bay and the Kattegat, respectively. Furthermore, because heterotrophic dinoflagellates were found to be as important grazers as ciliates in both systems, it was concluded that protozooplankton at high latitudes are also important in the cycling of primary production and should be considered if carbon and nutrient cycling in these systems is to be understood.During the past decade it has been shown that ciliates and heterotrophic dinoflagellates are abundant in arctic marine waters; these protists have higher growth capacities than copepods from the genus Calanus, which traditionally have been considered the principal grazers associated with high latitudes (Andersen 1988;Nielsen and Hansen 1995;Hansen et al 1996;Sherr et al 1997;Levinsen et al 2000a). Furthermore, adult and nauplii of the Calanus species have been shown to preferentially feed on ciliates and dinoflagellates (Barthel 1988;Ohman and Runge 1994; Levinsen et al 1 To whom correspondence should be addressed.…”

“…During the past decade it has been shown that ciliates and heterotrophic dinoflagellates are abundant in arctic marine waters; these protists have higher growth capacities than copepods from the genus Calanus, which traditionally have been considered the principal grazers associated with high latitudes (Andersen 1988;Nielsen and Hansen 1995;Hansen et al 1996;Sherr et al 1997;Levinsen et al 2000a). Furthermore, adult and nauplii of the Calanus species have been shown to preferentially feed on ciliates and dinoflagellates (Barthel 1988;Ohman and Runge 1994;Levinsen et al 2000b;Turner et al 2001).…”

“…Furthermore, adult and nauplii of the Calanus species have been shown to preferentially feed on ciliates and dinoflagellates (Barthel 1988;Ohman and Runge 1994;Levinsen et al 2000b;Turner et al 2001). Such results infer that ciliates and heterotrophic dinoflagellates play an important role in the cycling of pelagic primary production in arctic regions, similar to their role at temperate latitudes.…”