Aquatic Sciences Meeting, Albuquerque 2001

CS37 Zooplankton

Date: Wednesday, February 14, 2001, Time: 10:15:00 AM

Location: Aztec

Bussey, H, J, Memorial University of Newfoundland, St. John's, Canada, hbussey@ganymede.cs.mun.ca

Rivkin, R, B, Memorial University of Newfoundland, St. John's , Canada, rrivkin@morgan.ucs.mun.ca

Pakulski, J, D, University of West Florida, Pensacola, USA, jpakulski@uwf.edu

Ptak, M, , Memorial University of Newfoundland, St. John's, Canada, ptak@morgan.ucs.mun.ca

Anderson, M, R, Northwest Atlantic Fisheries Center, St. John's, Canada, and0629@ibm.net

Deibel, D, , Memorial University of Newfoundland, St. John's, Canada, ddeibel@morgan.ucs.mun.ca

MICROZOOPLANKTON HERBIVORY AND BACTERIVORY IN THE NORTH WATER POLYNYA

Polynyas are regions of reduced ice cover in high latitude environments, which are ordinarily ice-covered. To date, there are few comprehensive studies of microbial processes in polynyas yet productivity of phytoplankton and metazoans is greater than surrounding regions. Here we report rates and patterns of microzooplankton herbivory and bacterivory in the North Water polynya, from April through July, 1998. A phytoplankton bloom in May was followed by a corresponding increase in bacterial biomass (abundances were 1 to 22 x 10^8 cells/L from April to June). Growth rates of microbial prey ranged from 0.08 to 1.14 per day for phytoplankton (e.g. Chlorophyll a ) and 0.16 to 1.23 day^-1 for bacteria. Grazing mortality was maximal for bacteria in July yet phytoplankton grazing mortality was much lower and occurred generally in May. Preliminary investigation into grazing trends, using high-resolution image analysis, indicates that microzooplankton feed selectively on large size bacteria. A substantial amount of carbon is exported through the microbial food web in the North Water suggesting that microbial processes have a critical impact on cycling of biogenic carbon in polar regions.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

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