Haecky, P. University of Umeň, pia.haecky@micro.umu.se
Andersson, A. University of Umeň, agneta.nordstrom@umf.umu.se

 
PRIMARY AND BACTERIAL PRODUCTION IN SEA ICE IN THE GULF OF BOTHNIA
 
The primary and bacterial production in sea ice in the northern Gulf of Bothnia was studied throughout the ice covered winter season 1996 in order to determine limiting factors. During the first part of the ice-covered season, the ice algae appeared to be limited by light, while nutrients and predation appeared to be limiting during the last part of the ice-covered season. Sea ice pores are interesting model environments for studying microbial population dynamics, strongly influenced by physical factors such as temperature, snow cover, and flushing. Rapid algal growth was triggered in spring when snow-cover quickly melted, resulting in a succession of species prior to the melting of the ice. Bacterial biomass fluctuated between 60 - 160 Ámol C m-2 during the ice covered season, and appeared to be coupled to the availability of organic carbon from primary producers through grazing. The bacterial growth rate, calculated from the frequency of dividing bacterial cells (FDC), peaked after a period with declining chla concentration within the ice (11 Ámol C m-2 day-1). After this, fluctuations in the bacterial biomass were ascribed to periods of strong grazing followed by bacterial growth.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: SS27TU1206S