KANDUNGAN BAHAN ORGANIK SEDIMEN DAN KADAR H2S AIR DI DALAM DAN DI LUAR TEGAKAN MANGROVE DESA BEDONO, KABUPATEN DEMAK - Afiati, Norma; Purnomo, Pujiono Wahyu; Sa’diyah, Halimatus (Fakultas Perikanan dan Ilmu Kelautan, Universitas Diponegoro, 2018)
Kawasan mangrove dapat memproduksi bahan organik dari proses dekomposisi serasah yang jatuh yang menjadi penyuplai nuterien ke lingkungannya. Proses tersebut menggunakan oksigen terlarut yang apabila oksigen terlarut habis maka proses tersebut beralih ke proses dekomposisi secara anaerob yang menyebabkan terbentuknya senyawa H2S. Penelitian ini bertujuan untuk mengetahui perbedaan kandungan bahan organik sedimen dan kadar H2S air di dalam dan di luar kawasan mangrove serta untuk mengetahui hubungan kandungan kadar H2S air dengan bahan organik sedimen dan oksigen terlarut di kawasan mangrove desa Bedono. Metode penelitian adalah metode survey. Penelitian ini dilakasanakn pada bulan Mei- Juni 2017 di lokasi yang mewakili kawasan mangrove dan lingkungan sekitarnya. Data yang diukur adalah suhu air, kecerahan, kedalaman, kecepatan arus, oksigen terlarut, pH, bahan organik sedimen dan H2S air yang dilaksanakan empat kali dengan selang pengukuran dua minggu. Hasil yang didapat yaitu suhu air 28-31oC, kecerahan 14,5-68 cm, kedalaman 33-165 cm, kecepatan arus 0-0,1 m/s, oksigen terlarut , pH 5-6, bahan organik sedimen 7,73-20,27%, H2S air 0,003-0,037 mg/l. Kandungan bahan organik sedimen dan kadar H2S air tertinggi di dalam kawasan mangrove dengan rata-rata 16,36% dan 0,031 mg/l, dan terendah di luar kawasan mangrove dengan rata-rata 9,78% dan 0,01 mg/l. Kadar H2S tinggi di dalam kawasan mangrove dan lebih rendah di luar kawasan mangrove. Kadar H2S air dengan bahan organik sedimen dan oksigen terlarut berhubungan linier dengan persamaan H2S= 0,027 + 0,001BOS- 0,006 DO (r= 0,7246, BOS= Bahan Organik Sedimen, DO= Dissolved Oxygen). Mangroves produce organic matter from the decomposition of falling leaves, twigs etc, which supply nutrient to the environment. The process uses dissolved oxygen; when dissolved oxygen exhausted, it switches into anaerobic decomposition which causes the formation of H2S compounds. This study aims to knowing differences in sediment organic materials and H2S within and adjacent of mangrove areas and to determine the relation of H2S with sediment organic materials and dissolved oxygen in the mangrove areas of Bedono. Survey method is refered, and the study was conducted in May - June 2017 on locations representing mangrove areas and the surrounding environment. The data measured are water temperature, brightness, depth, current speed, dissolved oxygen, pH, sediment organic materials and H2S in the water. Sampling was conducted four times every fortnight. The result of the water temperature is 28-31 ° C, brightness 14.5 to 68 cm, 33-165 cm depth, current speed 0-0.1 m/s, dissolved oxygen 2-5,2 mg/l, pH 5-6, sediment organic material 7,73 to 20.27%, H2S 0.003 to 0.037 mg/l. Sediment organic materials and H2S were highest within the mangrove area, with an average 16.36% and 0.031 mg/l, and the lowest outside of mangrove area with an average 9.78% and 0.01 mg/l. H2S higher in the inside of the mangrove areas compared to the outside of it. The relation of H2S with sediment organic materials and dissolved oxygen is linearly related according to the equation H2S= 0.027+ 0.001SOM- 0.006DO (r= 0.7246, SOM= Sediment Organic Materials, DO= Dissolved Oxygen).