Journal

Changes Carbon, Nitrogen and Phosphor Compounds of Avicennia marina Leaf Litter During Decomposition in the Various Salinity Level In the Bay of Tapian Nauli. Yunasfi, Dwi Suryanto dan Wijiyono Fakultas Matematika dan Ilmu Pengetahuan Alam, Departemen Biologi Universitas Sumatera Utara, Jl. Tri darma The aims of this study were investigated the effect of salinity level on the remaining in the C, N and P during the process of composition of the A. marina leaf litter. 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 research indicated that the salinity level were influenced to C, N and P remaining in the leaf litter a long decomposition period. Sampel were analyzed for change in total C, N and P during decomposition period.The highest content of C was found in the leaf litter decomposed at 0 - 10 ppt, while the lowest content of C was found in the leaf litter decomposed at >30 ppt. The highest content of N was found in the leaf litter at 10 - 20 ppt, whereas the lowest content of N was found in the leaf litter decomposed at 20 - 30 ppt. The highest content of P was found in the leaf litter decomposed at > 30 ppt, whereas the lowest content of P was found in the leaf litter at 20 - 30 ppt. The N, P content increased during decomposition period. Key words: Avicennia marina, decomposition, leaf litter, mangrove, salinity.