Experimental study on the effect of salinity on growth rates of Arctic-sea-ice algae from the Greenland Sea

An Arctic bottom ice algal community collected from a pack ice floe in the Greenland Sea in autumn 1995 was cultured at 10 salinities ranging from 4.0 to 90.8 PSU for 19 days. Growth of species was determined by microscopical analysis of samples taken every 3 to 5 days. During the experiment the abundance of the algae increased over a wide salinity range from 4.0 to 74.0 PSU, but decreased at the highest salinity (90.8). Maximum growth rates were 0.29 d for the entire ice algal community and 0.42 d for individual taxa. The final composition of the algal communities varied with salinities. Phytoflagellates and Chaetoceros spp. were most abundant at low salinities (≤ 12.2), while pennate diatoms of the genus Nitzschia were the dominant algae at higher salinities.