CARBON STOCK ESTIMATION AT SEAGRASS MEADOWS IN NYAMUK ISLAND AND KEMUJAN ISLAND, NATIONAL MARINE RESERVE KARIMUNJAWA, JEPARA | ESTIMASI STOK KARBON DI PADANG LAMUN PULAU NYAMUK DAN PULAU KEMUJAN, BALAI TAMAN NASIONAL KARIMUNJAWA, JEPARA

English. Blue carbon is carbon absorbed and stored as biomass in coastal ecosystems. Seagrass meadows have the primary function of storing carbon. This study aims to determine the percentage of organic carbon content in the biomass and in the seagrass sediments, as well as total carbon stock in part of the National Marine Reserve Karimunjawa.The density and coverage of seagrass were made by means of quadrat transect and carbon content analysis was performed using Loss on Ignition (LoI) method. The highest average of organic carbon content percentage on belowground biomass was 33.13%, whereas from the aboveground biomass was 29.19% and in the sediment were 2.75% and 2.82% at Nyamuk Island (Station 1). Belowground biomass has higher carbon content than the aboveground, except for genus Halophila. Percentage of carbon weight in the sediment proved to be the highest contribution to the total carbon stock in seagrass meadows, i.e., 97.92-98.49%. The highest carbon weight was also established in Nyamuk Island,  i.e.,13248.29 tons C/ha. Whereas, Pokemon beach in Kemujan Island (Station 2) fixing the highest carbon stock, i.e., 83003.14 tons C in its 7.68 ha seagrass area.

Indonesian. Blue carbon adalah karbon yang diserap dan disimpan di ekosistem pesisir dalam bentuk biomassa. Padang lamun memiliki fungsi utama sebagai penyimpan karbon biru. Penelitian ini bertujuan untuk mengetahui persentase karbon organik biomassa dan di sedimen lamun, serta total stok karbon di sebagian BTN Karimunjawa. Kerapatan dan tutupan lamun diakses melalui transek kuadran dan analisis kandungan karbon organik dilakukan dengan metode Loss on Ignition (LoI). Kandungan karbon organik rata-rata tertinggi di ketiga stasiun berada di Pulau Nyamuk (Stasiun 1) dengan persentase dari biomassa-bawah sebesar 33,13%, biomassa atas-sedimen 29,19% dan pada sedimen masing-masing sebesar 2,75% dan 2,82%. Berat karbon biomassa bawah lebih besar daripada biomassa atas kecuali pada genus Halophila. Berat karbon sedimen memiliki persentase kontribusi tertinggi terhadap total stok karbon di padang lamun yaitu 97,92-98,49%. Stok karbon tertinggi juga berada di Pulau Nyamuk (Stasiun 1) yaitu sebesar 13248,29 ton C/ha. Pantai Pokemon Pulau Kemujan (Stasiun 2) dengan luas padang lamun 7,68 ha menambat total stok karbon paling tinggi, yakni 83003,14 ton C.