DYNAMICS, BIOMASS AND TOTAL RHIZOME LENGTH OF THE SEAGRASS THALASSODENDRON CILIATUM AT INHACA ISLAND, MOZAMBIQUE

Dynamic and structural aspects of Thalassodendron ciliatum were studie d in the intertidal zones around Inhaca Island during the rainy season s 1991 to 1993. Measurements comprised leaf growth rate, leaf detachme nt rate, biomass, above-ground to below-ground biomass ratios and tota l rhizome length. On average, three leaves were? at the same time, for med and detached from a shoot during 15 day periods and five leaves fr om a shoot during 30 day periods. Mean leaf growth rate varied from 10 1.2 to 159.5 mm, 313.2 to 366.9 mm and 540 to 583.0 mm for 15, 30 and 45 days of measurements respectively. Differences between locations (B anco Sidzanye, Barreira Vermelha and Portinho-EBM/BV) were not statist ically significant for the 30 and the 45 day period, but significant f or the 15-day period. The average leaf growth rate per day was between 14.1 to 18.3 mm day(-1) shoot(-1), and the average time for leaf turn over (6 to 9 leaves) on one shoot was four successive spring tides (ar ound 45 days). The average above-ground to below-ground biomass ratio was 1: 1.5 (61% in below-ground biomass) and leaf biomass varied betwe en 45.1 and 211.7 g DW m(-2). Total rhizome length varied between 960. 0 to 6641.6 cm m(-2). A positive correlation was observed between this Variable with rhizomes and roots and between rhizomes and roots.