Summer macroalgal biomass in Potter Cove, South Shetland Islands, Antarctica: Its production and flux to the ecosystem

Summer macroalgal biomass and production were analyzed at Potter Cove, King George Island, Antarctica and the potential carbon transfer of macroalgal production to the coastal ecosystem of the cove was estimated. A total of 38 algal species were found, with Desmarestia anceps, D. menziesii and Himantothallus grandifolius accounting for almost 80% of the biomass. Biomass data and published growth rates were combined to calculate the production of the five most abundant species. The standing stock for each summer month was estimated as the product of the average biomass and the area of the macroalgal stands. The monthly biomass production was calculated for each species by difference between the expected biomass and the observed biomass at the previous month. The macroalgal production showed a decreasing trend during the summer months. The average standing stock in the whole cove was 792.84 MT and the production was 1,401.33 MT during the summer 1994-1995. The flux of biomass to the ecosystem during the summer period was 1,370.61 MT, which is almost as much as the total summer production. The study demonstrates that macroalgae are one of the main energy sources in Potter Cove, and probably support a large fraction of the secondary production of the benthos.