Kinetics and trophic role of bacterial degradation of macro-algae in Antarctic coastal waters.

Abstract

Aerobic formation of detritus from debris of Himantothallus grandifolius yielded amounts of C and N 2 and 4 times higher, respectively, than fresh algae, and a concomitant decrease of the C:N ratio from 19 to approx 10. These changes were achieved only in the presence of the indigenous Antarctic bacterio-flora. During formation of detritus from the Antarctic red alga, Leptosomia simplex, C:N ratios may drop even below the Redfield ratio reported for phytoplankton. Results favour the idea that the formation of macro-algal detritus in Antarctic coastal waters is as efficient as in temperate regions. Partly degraded thalli from both the brown and red algae were preferred over fresh thalli, as a food source, by intertidal amphipods.-from Authors