VERTICAL-DISTRIBUTION OF ANTARCTIC PENINSULAR MACROALGAE - COVER, BIOMASS AND SPECIES COMPOSITION

The biomass and percentage cover of subtidal macroalgae were recorded at five sites near Anvers Island, along the Antarctic Peninsula (64 de grees S, 64 degrees W) in 1989. Total macroalgal wet biomass ranged fr om 1.64 to 6.34 kg m(-2). The largest biomass contributors were the la rge overstory brown algae (Phaeophyceae) Desmarestia antarctica Moe et Silva, Desmarestia menziesii. J. Agardh, Desmarestia anceps Montagne and Himantothallus grandifolius (Skottsberg) Zinova. These species had an overall cover of 72% of the bottom. D. menziesii and/or D. anceps were dominant at 2 and 5 m. D. antarctica dominated the overstory at 1 0 and 15 m. H. grandifolius was also abundant at 15 m and dominated at 20 m. Several red macroalgae (Rhodophyta) were also conspicuous: Irid aea cordata (Turner) Bory and Curdiea racovitzae Harlot at 2 and 5 m; Myriogramme mangini (Gain) Skottsberg and Plocamium cartilagineum (Lin naeus) Dixon at 10 and 15 m; and Gigartina skottsbergii Setchell et Ga rdner and Sarcodia montagneana (Hooker et Harvey) J. Agardh at 15 and 20 m. The presence of large quantities of epilithic D. antarctica at 1 0 and 15 m was very unusual, as this species has previously been descr ibed as an obligate epiphyte with a depth distribution restricted to < 10 m.