Distribution of and Feeding by the Copepod Pseudocalanus Under Fast Ice During the Arctic Spring

Abstract

The arctic copepod Pseudocalanus can be highly aggregated in the first few centimeters under landfast ice during spring in concentrations up to 10/(6) per cubic meter. Chlorophyll-derived pigments in the water, the abundance of animals, and their gut pigment index show fluctuations that may be tidally related. Short-term grazing experiments performed at -1.7 degrees C, in which ice algae was used as food, yielded feeding rates comparable to the highest known for the genus. Arctic Pseudocalanus seem to feed opportunistically near the ice-water interface, either directly on the attached epontic (under ice) algae or as it erodes from the ice.

Mesoscale distribution and functional diversity of picoeukaryotes in the first-year sea ice of the Canadian Arctic

“…On the other hand, sea ice provides a unique habitat for diverse and highly productive microbial communities (Gradinger, 2009;Deming, 2010). Ice algae form the base of the polar food web before the melting of sea ice (for example, (Conover et al, 1986;Werner, 1997), as ice-algal fatty acids are essential for the development of key Arctic zooplankton species (Soreide et al, 2010).…”

Grazing of Arctic under-ice amphipods on sea-ice algae

“…For instance, the sea-ice meiofauna is believed to exploit this food source as well (Grainger et al 1985, Grainger & Hsiao 1990, Grainger 1991. Additionally, several pelagic species depend on released ice algae as early food in spring (Conover et al 1986, Runge & Ingram 1988. In perennial sea ice, ungrazed organic matter can accumulate during the productive season and may represent an important food source for the ice fauna during winter (Melnikov 1997).…”

“…4 to 100% for Pseudocalanus spp. (Hanssen 1997 and references therein) and 6 to 91% for Calanus glacialis (Conover et al 1986). Feeding on ice organisms, larvae of the Antarctic krill Euphausia superba ingest 2 to 44 % of their body carbon per day, which probably covers the metabolic requirements for growth and development (Daly 1990).…”

Trophic relationships and pelagic–benthic coupling during summer in the Barents Sea Marginal Ice Zone, revealed by stable carbon and nitrogen isotope measurements

“…zooplankton and benthos, however, remains to be quantified. Grazing by copepods on ice algae at the ice-water interface has been observed in the Canadian Arctic (Conover et al 1986), which suggests that ice algae may be an important early season food source before phytoplankton become abundant.…”