Underice grazing by planktonic, calanoid copepods in relation to a bloom of ice microalgae in southeastern Hudson Bay

• Published in: Limnology and Oceanography
• Main Authors: Runge, Jeffrey A., Ingram, R. Grant
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1988
• Subjects: Arctic; Hudson; Hudson Bay; Calanus glacialis; Phytoplankton; Copepods
• Online Access: http://dx.doi.org/10.4319/lo.1988.33.2.0280; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.1988.33.2.0280; https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1988.33.2.0280

A spring bloom of ice microalgae was observed at a station on southeastern Hudson Bay. Levels of pheopigments in guts of females of Calanus glacialis and Pseudocalanus spp., the dominant calanoid copepods in this region, increased by an order of magnitude after onset of the bloom. Feeding had a diel cycle and was associated with a nighttime migration of females to the ice‐water interface. Fragments of pennate, ice diatoms were observed microscopically in most guts of Calanus and Metridia, but only rarely in Pseudocalanus, which may have been feeding on flagellates associated with the ice‐water interface. The results suggest that ice microalgae in Hudson Bay are a regular and significant source of nutrition for planktonic copepods before the phytoplankton bloom. The structure of the layer at the ice‐water interface may influence feeding behavior on ice microalgae by arctic copepods.