Struktur Komunitas dan Kelimpahan Fitoplankton dan Zooplankton pada Musim Penghujan di Zona Intertidal Pantai Selatan Yogyakarta

Abstract

Plankton is an organism that plays an important role as a water food reserve, which is influenced by environmental conditions. This study aims to determine the community structure, abundance and biodiversity of phytoplankton and zooplankton in the intertidal zone of south coast of Yogyakarta during the rainy season. The research was conducted at Pantai Drini, Kukup, and Sundak of Gunungkidul District during December 2016 - February 2017. Sampling was conducted on three observation stations in the intertidal zone of Drini Beach, Kukup, and Sundak twice a month. The water samples were taken with plankton nets number 25, then were fluidized in 4% formalin and stored at low temperatures. The results showed diversity index of plankton in Kukup Beach in January at 1.86 while the lowest value in February at Sundak Beach was 0.87. The highest plankton abundance in January at Sundak Beach was 900 individu L^-1 while the lowest value in December at Kukup Beach was 217.8 individu L^-1. Based on the diversity index of Shannon-Wiener, intertidal coast waters of Yogyakarta in wet season is categorized as moderate, and dominance index is categorized  as low.

Plankton merupakan organisme yang berperan penting sebagai cadangan makanan perairan dan dipengaruhi oleh kondisi lingkungan. Penelitian ini bertujuan untuk mengetahui struktur komunitas, kelimpahan dan keanekaragaman plankton pada zona inertidal pantai selatan Yogyakarta selama musim penghujan. Penelitian dilakukan di Pantai Drini, Kukup, dan Sundak Kabupaten Gunungkidul selama bulan Desember 2016 – Februari 2017. Pengambilan sampel dilakukan pada tiga stasium pengamatan di zona intertidal Pantai Drini, Kukup, dan Sundak setiap dua minggu. Sampel air diambil dengan jaring plankton nomor 25, kemudian sampel plankton difiksasi dalam formalin 4% dan disimpan pada suhu rendah. Hasil penelitian menunjukan indeks keanekaragaman jenis plankton tetinggi di Pantai Kukup pada bulan Januari sebesar 1,86 sedangkan nilai terendah pada bulan Februari di Pantai Sundak sebesar 0,87. Kelimpahan plankton tertinggi pada bulan Januari pada Pantai Sundak sebesar 900 individu L^-1 sedangkan nilai terendah pada bulan Desember di Pantai Kukup yaitu 217,8 individu L^-1. Berdasarkan indeks keanekaragaman Shannon-Wienner maka indeks keanekaragaman di pantai selatan Yogyakarta tergolong rendah-sedang dengan indeks dominansi tergolong rendah.