RASIO C/N TERHADAP BAHAN ORGANIK DAN TOTAL BAKTERI PADA SEDIMEN DI HABITAT RAJUNGAN (Portunus pelagicus) PANTAI BETAHWALANG, KABUPATEN DEMAK - Putri, Megawati Arsita; Afiati, Norma; Purnomo, Pujiono Wahyu (Departemen Sumberdaya Akuatik,Fakultas Perikanan dan Ilmu Kelautan, Universitas Diponegoro, 2015)
Salah satu indikasi konstribusi bahan organik terhadap kesuburan perairan adalah rasio C/N. Karbon dan nitrogen adalah dua komponen pokok bahan organik. Kandungan karbon organik dalam sedimen berkaitan dengan faktor karakteristik sedimen, laju degradasi mikroba, produktivitas kolom air. Pantai Betahwalang direncanakan menjadi kawasan lindungan laut daerah untuk komoditas rajungan (Portunus pelagicus). Oleh karena itu, ingin dipelajari bagaimana kondisi/status dekomposisi di lingkungan sedimen pantai Betahwalang berdasarkan kandungan bahan organik, rasio C/N, jumlah total bakteri sedimen dan korelasi antar ketiga komponen tersebut. Untuk itu digunakan metode survei dengan teknik pengambilan sampel bersifat purposive random. Dalam penelitian ini digunakan data primer dan sekunder. Analisis data menggunakan chi kuadrat, regresi dan korelasi. Hasil penelitian menunjukkan status dekomposisi sedimen pantai Betahwalang, Kabupaten Demak berlangsung relatif sempurna ditinjau dari rasio C/N yang lebih kecil dari angka 20 yaitu berkisar antara 4,36 – 5,27 yang menunjukkan terjadinya proses mineralisasi N (nitrogen), dengan kandungan bahan organik (4 – 7%) dan total bakteri berkisar antara 7,4 x 105 – 17,25 x 105 cfu/ml. One of indication of contribution organic materials to water fertility is the C/N ratio. Carbon and nitrogen are two main component of organic material. Among others, content of organic carbon in sediment related to the sediment characteristic factors, rate of microbial degradation productivity of the water column.. Therefore, need a study to see how much the decomposition process in the Betahwalang coastal sediment based on organic materials content, C/N ratio and the total number of bacteria sediment. The purpose of this study to determine the condition of coastal sediments Betahwalang decomposition, Demak district based on organic materials, C/N ratio and total bacteria in the sediment. The method used in this study is survey which conduct towards a set of objects with the assumption that object under study has represented the area observed. Data retrieval include research data and sampling. Research data were used primary and secondary data. The method sampling used purposive random sampling. Data analysis used chi squared, regression and correlation. The results showed decomposition status sediments Betahwalang Beach, Demak is perfect decomposition views of C/N ratio content, organic matter and total bacteria. The content of organic matter is relatively low ranging between 4 – 7%. The content of the C/N ratio ranged between 4,36 – 5,27 including high level category into decomposition, because the ratio C/N is smaller than figure 20 showed occurrence process of mineralized N (nitrogen). The average concentration of bacteria ranged between 7,4 x 105 – 17,25 x 105 cfu/ml.