Leaf Litter Decomposition in the Mangrove Ecosystems of Dutch Bay
The ecological significance of mangals stems from their high primary productivity and the capacity to support aquatic food webs through the production of detritus. Present study is an attempt to have an insight into the ability of the mangrove ecosystems (mangals) of Dutch bay, namely, the riverine mangals at Kala Oya estuary and the fringing mangals at Erumathivu island, in performing this function. Avicennia marina leaf litter lost half its original weight within 30 days and Rhizophora mucronata within 2-90 days. Average daily rates of litter decomposition in the fringe mangals (0.0201 g day -1 - 0.1095 g day' for A. marina and 0.0111 g day' - 1.2111 g day' for R. mucronata), were higher than those in the riverine mangals (0.0293 g dayl- 0.0778 g day' for A. marina and 0.0075 g day' - 0.0216 g day' for R. mucronata). The average daily litter decomposition rates in the water-front zones (average rate of 0.0343 g day' at Kala Oya and 0.4883 g day' at Erumathivu) were found to be greater than that of the landward zones of the respective manes. The gastropod, Terebralia palustris appears to play an important role in leaf litter breakdown in these mangals.