KELIMPAHAN DAN KELOMPOK FITOPLANKTON DI PERAIRAN LUAR TELUK WONDAMA, PROVINSI PAPUA BARAT

Abstract

ABSTRAKKelimpahan sel fitoplankton di perairan laut tergantung pada kualitas kelompok fitoplakton dan parameter oseanografi. Penelitian bertujuan mengetahui kelimpahan dan kelompok fitoplankton serta hubungannya dengan suhu, pH, salinitas, amonia, nitrat, dan silikat. Penelitian berlangsung dari bulan Juli 2014 sampai September 2014 di perairan sekitar Pulau Roswar dan Roon bagian luar Teluk Wondama. Identifikasi fitoplankton dilakukan dengan metode sensus di atas Sedgwick Rafter Cell. Pengukuran konsentrasi amonia, nitrat, dan silikat secara berturut-turut dengan metode penat, brusin, dan molibdosilikat. Hasil menunjukkan total rata-rata kelimpahan sel fitoplankton sebesar  274,541±214,873 sel/m3  dan tertinggi pada bulan Agustus  sebesar 462,951±210,802 sel/m3 (P<0,005). Kelompok fitoplankton dan kontribusinya pada total kelimpahan fitoplankton terdiri dari Bacillariophyceae (31,28%), Cyanophyceae (64,43%), Dinophyceae (4,24%), dan Chrysophyceae (0,02%). Nilai suhu, pH dan salinitas serta konsentrasi amonia dan silikat homogen dengan nilai rata-rata secara berturut-turut sebear 29,6±0,07°C, 8,2±0,04, 32,3±0,07‰, 0,04±0,01 mg/L, 0,31±0,09 mg/L. Berbeda dari   nitrat konsentrasinya tinggi pada bulan September dengan rata-rata sebesar 0,02±0,01 mg/L (P<0,005). Kelimpahan sel fitoplankton sangat tergantung pada amonia, nitrat dan silikat (hubungan positif) terutama nitrat (R2 = 54,4%). ABSTRACTMarine phytoplankton abundance depends on the quality of phytoplankton groups and oceanographic parameters. The purposes of this study were examining the abundance and phytoplankton group and its relation with temperature, pH, salinity, ammonia, nitrate and silicate. The study were started  from July 2014 to September 2014 in the Roswar and Roon island in outer waters of the Wondama Bay.  Identification of the abundance phytoplankton calculated by census method with a Sedgwick Rafter Cell. While, the measurement of ammonia, nitrate, and silicate concentrations successively using the method of penat, brusin, and molybdosilicat. The results showed that total mean of phytoplankton cell abundance of 274.541±214.873 cell/m3 and the highest in August of 462.951±210.802 cell/m3 (P<0.005). The phytoplankton groups and its contribution on the total abundance of phytoplankton consisted of Bacillariophyceae (31.28%), Cyanophyceae (64.43%), Dinophyceae (4.24%), and Chrysophyceae (0.02%). The values of temperatures, pH and salinities as well as the concentrations of homogeneous ammonia and silicate with values mean were 29.6±0.07°C, 8.2±0.04, 32.3±0.07‰, 0.04±0.01 mg/L, 0.31±0.09 mg/L, respectively. In contrast to nitrates, high concentration was found in September with an mean of 0.02±0.01 mg/L (P<0.005). The abundance of phytoplankton cells is highly dependent on ammonia, nitrate and silicate (positive corelation) especially nitrate (R2 = 54.4%).