Productivity and decomposition rate of Rhizophora mucronata and Avicennia alba litter based on environment characteristics in Muara Gembong

Abstract

Mangrove forests damage may decrease their function and ecological role in relation to litter production which support the sustenance of aquatic resources. This research aimed to determine and estimate productivity and decomposition rate of mangrove Rhizophora mucronata and Avicennia alba litter, and their effect on water nutrients. The research was conducted at three stations in Pantai Mekar Village, Muara Gembong District for 60 days observation during period of April-September 2018. Litter productivity was measured using litter traps and litter decomposition rate was estimated using litter bags. The concentration of water nutrient (nitrate, ammonium and phosphate) was obtained through a laboratory analysis. Litter productivity of R. mucronata and A. alba stands reached 4.68 and 7.11 g m-2 day-1 respectively with the biggest contributed from leaves litter. Observed different rates of mangrove decomposition was due to the lignin content. The decomposition rate of R. mucronata and A. alba were Y=12.841e-0.382X (R2=0.97) and Y=11.958e-0.478X (R2=0.91) respectively. The productivity and decomposition rate of A. alba litter was greater and faster than R. mucronata. Increased nitrates was indicated of nitrification process, while phosphate and ammonium showed decreased concentration during experiments. Aside from that, water nutrient concentration was affected by dissolved oxygen availability.