Kemelimpahan Komunitas Zooplankton di Perairan Hutan Bakau Segara Anakan, Cilacap

ADIB MUHAMMAD AHSAN, Prof. Dr. Tjut Sugandawaty Djohan, M.Sc.

2023 | Skripsi | S1 BIOLOGI

Penelitian ini mempelajari kemelimpahan komunitas zooplankton di perairan hutan bakau Segara Anakan (SA), Cilacap pada awal musim kemarau Juli 2020. Zooplankton berperan penting pada jejaring makanan perairan sebagai penghubung antara produsen dan konsumen sekunder. Perairan hutan bakau SA mengalami kerusakan hutan bakau dan sedimentasi tinggi. Penelitian dilakukan di tiga lokasi perairan: Bondan, Klaces, dan Kali Gatal. Pengambilan sampel air menggunakan modifikasi Van Dorn sebanyak 20 L, dengan 5 ulangan. Sampel kemudian disaring dengan Wisconsin Plankton-Net 120 mesh lalu difiksasi dengan formalin. Parameter yang diukur: ammonium, nitrat, fosfat, sulfat, oksigen terlarut, salinitas, turbiditas, jeluk secchi, intensitas cahaya, kelembaban dan suhu udara, suhu dan pH air, jeluk perairan, dan kecepatan arus. Data kemudian disajikan dalam diagram batang, pie, dan ordinasi bray-curtis. Hasil penelitian menemukan enam fungsional grup antara lain copepoda, rotifera, protozoa, ostracoda, foraminifera, dan larva planktonik. Cacah spesies zooplankton berkisar 29-31 sp/100L; sedangkan cacah individunya sangat sedikit, berkisar antara 407-9972 ind/100L. Komunitas zooplankton perairan SA didominasi oleh spesies laut. Spesies yang banyak ditemukan yaitu Clausocalanus pergens, Eucyclops prasinus, Acartia tonsa, Tintinnopsis spp, dan Difflugia corona. Kemelimpahan spesies asli payau juga sangat sedikit. Kemelimpahan cacah individu sangat sedikit disebabkan karena kemelimpahan fitoplankton yang bisa dimakan zooplankton sangat sedikit akibat kerusakan hutan bakau serta sedimentasi tinggi dari Sungai Citanduy. Kondisi ini ditandai dengan spesies yang hadir merupakan spesies yang mampu beradaptasi terhadap kondisi pakan terbatas. Hasil tersebut menunjukkan kemelimpahan komunitas zooplankton SA sedang terusik akibat ketersediaan pakan fitoplankton yang sangat sedikit.

This study investigates the abundance of zooplankton community in the SA mangrove waters, Cilacap at late dry season July 2020. Zooplankton have important role in the aquatic food-web as a link between producers-secondary consumers. SA waters are experiencing mangrove forest damage and high sedimentation rate. The study was conducted at: Bondan, Klaces, and Kali Gatal Waters. Samples were collected using a Van Dorn water sampler 20L, 5 replicates. The samples then filtered with Wisconsin Plankton-Net (120 mesh) and fixed with formalin. The parameters measured were: ammonium, nitrate, phosphate, sulfate, dissolved oxygen, salinity, turbidity, secchi depth, light intensity, air humidity and temperature, water temperature and pH, water depth, and current speed. The data presented in bar, pie, and bray-curtis ordination diagrams. The results found six functional groups: copepods, rotifers, protozoa, ostracods, foraminifera, and planktonic larvae. The number of zooplankton species ranges between 29-31 sp/100L; while the number of individuals is very small, 407-9972 ind/100L. The zooplankton community is dominated by marine species. The common species found were Clausocalanus pergens, Eucyclops prasinus, Acartia tonsa, Tintinnopsis spp., and Difflugia corona. The brackish species were also had very low abundance. The low individual abundance is due to the lack of availability of phytoplankton prey for zooplankton because mangrove forests and high sedimentation rate from Citanduy River. This condition is characterized by the presence of species that are able to adapt in limited food conditions. These results indicate that the abundance of SA zooplankton community was disturbed due to the lack of fitoplankton prey availability.

Kata Kunci : Detritus, Fitoplankton, Sedimentasi, Salinitas, Copepoda.