Decomposition of Cladophora. I. Field Studies in the Peel-Harvey Estuarine System, Western Australia

Abstract

Cladophora aff. albida is a benthic alga which gorws in nuisance proportions in the shallow (2 m) Peel-Harvey estuarine system in Western Australia. It grows as small (1-3 cm) ball-like clumps in beds 1-10 cm deep, the lower self-shaded sections of which are in various stages of decomposition. Samples of Cladophora (half of which were prekilled by freezing) were buried in a bed in nylon mesh bags for up to 1 yr. Initially live Cladophora was very resistant to decay; only after 2 mo. did significant decomposition begin, resulting in loss of 50-60% of dry weight, C, N and P over the next 2 mo. Little further losses occurred. Killed Cladophora began to decompose immediately and there was loss of 80% of P in 1 wk. Dry weight, C and N losses were slower (20-30% in 2 wk, 50% after 3 mo.). It was estimated that up to 60% of the Cladophora pool of N and P could be available for recycling in 1 yr. This reduces the dependance of Cladophora on eternal inputs to maintain production.