SEASONAL-VARIATION OF ALGAL GROWTH-CONDITIONS IN SHELTERED ANTARCTIC BAYS - THE EXAMPLE OF POTTER COVE (KING-GEORGE-ISLAND, SOUTH-SHETLAND)

Wind, air temperature, surface irradiance, light penetration into the water, salinity and water temperature have been recorded from mid Nove mber to mid February in Potter Cove, King George Island. Results are c ompared with published data on requirements for growth of Antarctic ma croalgae. The investigated season showed two distinct periods: Early s ummer lasted until end of December with comparatively cold temperature s, unstable water column and deep penetration of light; late summer st arted in early January and was characterized by reduced salinity due t o meltwater discharge and high turbidity due to suspended sediments. M eltwater influence did not sufficiently change salinity to be responsi ble for the frequently noted paucity of macroalgal communities in shel tered bays. Shading by suspended sediments was equally considered to b e of minor importance, as macroalgae have their optimal growth phase f rom September to December. During this period, light penetration and d epth distribution of macroalgae coincide perfectly. From these results , a general review on depth limitation of macroalgae by light conditio ns is derived.