Durvillaea antarctica production in relation to nutrient cycling at Marion Island.

Abstract

Total fresh mass of D. antarctica, approx 3300t (ww), is situated with varying proportion along each shore type of the island. Calorific content varies with season and with plant organ. Recruitment generally takes place after August on sites having become available after autumn and winter storms. Production in a re-colonizing stand of kelp sporelings is equivalent to 172X103kJm-2. Low erosion rate and high mortality is a feature of the D. antarctica population. The primary contributors to mortality are grazing by intertidal herbivores and occasional, violent storms. Holdfasts are weakened by boring isopods. Affected plants are torn free and cast onto beaches during storms, where they are attached by grazing Amphipoda in the spray zone. Beyond this zone, decomposition takes place through bacterial action.-from Authors