Spatial Distributions of Nutrients and Chlorophyll-A: a Possible Occurrence of Phosphorus as a Eutrophication Determinant of the Jakarta Bay

Abstract

Phytoplankton blooms due to nutrient enrichment (eutrophication) have been considered as the primary factor causing several massive fish kills occurred in the Jakarta Bay. This study aims to determine the spatial variation of phytoplankton abundance based on chlorophyll-a concentration and its relationship with nutrient level and composition. A field observation was conducted in July 2015 measuring chlorophyll-a and nutrient concentrations. Chlorophyll-a was measured using fluorometer Trilogy AU-10 while nutrients was using spectrophotometer Shimadzu UV-1800. The result showed that chlorophyll-a concentration was relatively higher in the western compared to the eastern region of the Jakarta Bay. In addition, the western region was high in orthophosphate, nitrate and silicate while the eastern region was high in ammonium and nitrate. Statistical analysis shows that chlorophyll-a had the highest significant correlation against orthophosphate in the western region and chlorophyll-a had no significant correlation with nutrients in the eastern region. It seems that phosphorus was the primary determinant of chlorophyll-a variability with a concentration of orthophosphate of more than 0.028 mg P/L is required to increase chlorophyll-a concentration. In addition, low orthophosphate concentration (0.014 mg P/L) below its minimum requirement for maximum phytoplankton growth was likely the factor causing the absence of chlorophyll-a and nutrients relationship in the eastern region. In summary, phosphorus is seemingly the primary eutrophication determinant in the Jakarta Bay.

Nutrients and chlorophyll-a concentration in Socah Estuary receiving shrimp pond waste, Bangkalan Regency

“…Sharker et al found similar results to the recent study, where phosphate and nitrate have a significantly positive correlation with chlorophyll-a in the Bay of Bengal [59]. Prayitno and Afdal also revealed similar results in observations conducted in Western Jakarta Bay, and the chlorophyll-a was found to have a positive and significant correlation with phosphate (r = 0.803, P<0.05) and nitrate (r = 0.673, P<0.05) [60]. Nitrate is one of the N (nitrogen) nutrients phytoplankton needs for growth.…”

Klorofil Lamun Dan Karakteristik Perairan Pantai Alang-Alang, Karimunjawa

“…Menurut (Prayitno & Afdal, 2019) kelarutan CO 2 bebas dalam air laut ini dimanfaatkan untuk aktifitas proses fotosintesis oleh makhluk hidup perairan. Biomassa dalam ekosistem lamun dapat berperan sebagai penyimpan karbon dioksida dari atmosfer.…”

Akumulasi Biomasa Fitoplankton yang Diukur sebagai Klorofil-a di Perairan Teluk Doreri, Provinsi Papua Barat

“…Konsentrasi klorofil-a di perairan pantai Maroon sebesar 1,09 mg/m 3 (Prihatin et al, 2018) dan muara Sungai Serang dengan rata-rata sebesar 1,76 mg/m 3 (Maslukah et al, 2017) setara dengan 1,09 μg/L dan 1,76 μg/L. Pada perairan muara Sungai Angke diperoleh konsentrasi klorofil-a dengan ratarata sebesar 3,19 μg/L (Prayitno & Afdal, 2019). Pada perairan muara sungai Tallo, Maros, dan Pangkep konsentrasi Klorofil-a secara berturut-turut dengan rata-rata sebesar 4,52 μg/L, 1,40 μg/L, 2,72 μg/L (Lukman et al, 2014).…”

“…Fenomena ini di sebagian besar perairan dunia meningkat frekuensi, intensitas dan distribusi geografis selama beberapa dekade terakhir (Blondeau-Patissier, et al, 2014) termasuk di perairan Indonesia. Pada beberapa perairan di Indonesia seperti Teluk Jakarta (Prayitno & Afdal, 2019) dan pesisir Sulawesi Selatan (Lukman et al, 2014) konsentrasi klorofil-a menunjukkan peningkatan.…”