ANALISIS KEBUTUHAN OKSIGEN UNTUK DEKOMPOSISI BAHAN ORGANIK SEDIMEN DI KAWASAN MANGROVE DESA BEDONO DEMAK
Authors: Sari Mia Arista , Purnomo Pujiono Wahyu , Haeruddin Haeruddin 
Published: September 2020

ABSTRAK Salah satu peran penting mangrove bagi kehidupan biota akuatik adalah sebagai penyedia nutrien dari bahan organik yang dihasilkan. Proses dekomposisi bahan organik membutuhkan oksigen dan bantuan bakteri. Apabila kadar oksigen berkurang maka dapat mempengaruhi proses dekomposisi dan akhirnya dapat berpengaruh terhadap kehidupan bentos yang ada. Tujuan dari penelitian adalah  mengetahui kebutuhan oksigen yang digunakan dalam proses dekomposisi bahan organik pada kawasan mangrove. Penelitian bersifat eksperimental terhadap deposit bahan organik. Penelitian mengacu pada rancangan acak lengkap dengan 3 perlakuan (deposit organik mangrove padat, sedang, dan jarang) yang masing – masing diulang 3 kali. Penelitian dilakukan di kawasan mangrove desa Bedono, Demak. Peubah utama yang diukur adalah Disolved Oxygen, bahan organik sedimen secara berkala pada jam ke- 0, 12, 24, 36, 48, 60 dan 66. Peubah tambahan yang diukur adalah kelimpahan bakteri. Diukur penurunan Disolved Oxigen pada waktu tertentu. Diukur pula nilai bahan organik sedimen dan kelimpahan koloni bakteri. Hasil yang didapat yaitu nilai kebutuhan oksigen sedimen tertinggi pada stasiun 1 dengan kisaran 1,3 – 3,5. Nilai kebutuhan oksigen sedimen pada stasiun 2 berkisar antara 1,2 – 2,2 dan nilai kebutuhan oksigen sedimen pada stasiun 3 berkisar antara 0,8 - 2,7. Hasil kelimpahan koloni bakteri pada stasiun 1 berkisar antara 1 x 1011 – 1,5 x 1011Cfu/ml. Stasiun 2 berkisar antara 2 x 1011 - 22 x 1011Cfu/ml dan stasiun 3 berkisar antara 1 x 1011 - 2 x 1011Cfu/ml. Kualitas perairan seperti temperatur berikisar antara 27 - 32 ºC. Nilai salinitas beriksar antara 25 - 29‰ dan nilai pH berkisar antara 7 - 8. Kata kunci: Oksigen; Bahan Organik; Sedimen; Dekomposisi ABSTRACT One important role of mangrove for aquatic biota is a provider of nutrients from organic matter produced. The process of decomposition of organic matter need oxygen and help the bacteria. When oxygen levelsdecreases, it can affect the decomposition process and can ultimately affect the existing benthic life. The purpose of the research was to determine the need of oxygen used in the decomposition of organic matter in the mangrove areas. It is a experimental research on the deposit of organic material. The research refers to a completely randomized design with 3 treatments (dense mangrove organic deposits, medium, and rare) that eachs repeated three times. Research conducted in the mangrove areas Bedono village, Demak. The main variables measured were Disolved Oxygen, sedimentary organic matter on a regular basis on the hour 0, 12, 24, 36, 48, 60 and 66. Additional variables that measured the abundance of bacteria.MeasuredDisolvedOxigen decline at a certain time. Measured the value of sedimentary organic matter and the abundance of bacterial colonies. The result is the highest value of the oxygen requirement of sediment at station 1 is in the range of 1,3 to 3,5. The value of the oxygen requirement of sediment at station 2 ranged from 1,2 to 2,2 and the value ofsediment oxygen demand of the three stations ranged from 0,8 to 2,7. The result of the abundance of bacteria colonies from the at station 1 range from 1 x 1011 to 1,5 x 1011Cfu/ml. Station 2 ranging from 2 x 1011 -22 x 1011Cfu/ml and three stations ranged between 1 x 1011 -2 x 1011Cfu/ml. Water quality  such as temperature ranged from 27 - 32 ºC. Salinity value ranged from 25 - 29 ‰ and pH values ranged from 7-8.                                                                                                                              Keywords: Oxygen; Organic Matter; Sediment; Decompotition