Mangrove Bacteria

Bacteria Diversity of Avicennia marina Leaf Litter During Decomposition in the Various Salinity Level In the Bay of Tapian Nauli. Yunasfi, Dwi Suryanto dan Wijiyono Facultas matemátika dan Ilmu Pengetahuan Alam, Departemen Biologi, Universitas Sumatera Utara, Jl. Tri darma, PO Box The aims of this study were investigated the effect of salinity level on the diversity of bacteria. The research has been conducted at the mangrove forest of Aek Horsik, Badiri, Central Tapanuli, North Sumatera. The leaf litter were collected using litter traps made of nylon mesh 2 mm pore.The traps were position under the A. marina trees in the mangrove forest. The leaf was collected for two weeks period. Litter bag was filled with 50 g leaf litter and put on the forest’s floor in four different salinity level, each salinity level with 24 litter bag. The litter bag was observed each 15 days of decomposition. The results of our investigation indicated that totally 16 species of bacteria were isolated from A. marina leaf litter undergoing the decomposition, including Bacillus (5 spesies), Pseudomonas (2 spesies), Aeromonas (1 species), Listeria (1 species), Kurthia (1 species), Escherechia (1 species), Planococcus (1 species), Micrococcus (2 species), Mycobacterium (1 species) dan Flavobacterium (1 species). The highest amounts of bacteria at 10 - 12 ppt were 1,28 x 109 cfu/, whereas the lowest of bacteria at >30 ppt were 0,35 x 109 cfu/ml. Bacillus subtilis was dominant species during decomposition period. The species diversity indices in the leaf litter decomposition at 0 - 10 ppt were 2.20, at 10 - 20 ppt were 2.38, at 20 - 30 were 2.03 and >30 ppt were 1.78. The frequency of the bacteria species colonization during the decomposition process ranged from 12.5 to 100%. Key words: Avicennia marina, bacteria, decomposition, diversity, leaf litter, mangrove, salinity.