KEANEKARAGAMAN DAN KELIMPAHAN DIATOM (BACILLARIOPHYCEAE) DI PANTAI JERANJANG DESA TAMAN AYU KECAMATAN GERUNG KABUPATEN LOMBOK BARAT

ABSTRAK Pantai Jeranjang yang terletak di desa Taman Ayu merupakan salah satu daerah buangan limbah cair karena terdapat PLTU (Pembangkit Listrik Tenaga Uap) yang menggunakan air laut sebagai pendingin dan akhirnya dibuang kembali ke laut. Tujuan penelitian ini yakni untuk mengetahui keanekaragaman dan kelimpahan diatom (Bacillariophyceae) di Pantai Jeranjang Desa Taman Ayu Kecamatan Gerung Kabupaten Lombok Barat. Metode penentuan titik sampling dan waktu sampling menggunakan purposive sampling method. Data diatom dianalisis untuk parameter indeks keanekaragaman, indeks kemelimpahan, indeks kemerataan dan nilai penting. Persen kesamaan antar stasiun ditentukan berdasarkan Bray Curtis Cluster Analysis menggunakan program biodiversity versi 2. Hasil penelitian menunjukkan spesies diatom yang teridentifikasi di Pantai Jeranjang terdiri dari 1 kelas, 2 ordo, 17 genus dan 26 spesies. Kemelimpahan spesies diatom di perairan Pantai Jeranjang sebesar 786,944individu/liter. Indeks keanekaragaman spesies diatom tergolong sedang yakni 1,383 dan kemerataan spesies diatom yakni 0,424 (penyebaran kurang merata). Hasil Bray-Curtis cluster analysis menunjukkan bahwa berdasarkan parameter biologi dan gabungan antara parameter bilogi dan parameter lingkungan, persen kesamaan tertinggi terdapat antara titik sampel I dan titik sampel II berturut-turut sebesar 78,781% dan 80,63%. Sedangkan berdasarkan parameter lingkungan persen kesamaan tertinggi terdapat antara titik  sampel I dan titik sampel III sebesar 99,030 %. Kata Kunci :Pantai Jeranjang, PLTU, Diatom ABSTRACTJeranjang coastal waters is a part of Taman Ayu village. The coastal waters of Jeranjang has been an area of liquid waste disposal of the Electric Steam Power Plant Jerajang. The purpose of this research were to know diversity and abundance of diatom (Bacillariophyceae) inthe coastal waters of Jerajang Taman Ayu village Gerung districts west Lombok. Sites and times of sampling were determined by using purposive sampling method. Data of diatom were analyzed for density,diversity, andevenness indexs and percentage important value. Percentage similarity of among stations was determined based on the Bray-Curtis cluster analysis using biodiversity program-version two. The results showed that diatom species of Jeranjang coastal waters consist of 1 class, 2 orders, 17 genus and 26 species. The abundance of diatom community in Jeranjang coastal waters was 786,944individu/liter. Diversity and evenness indexs of diatom species were 1,383 (intermediate status) and 0,424  (lack of dispersal). The highest percentage similarity was on biological parameters and the relationship between biological parameters and environmental parameters for between sample site I and sample site II (78,781% and 80,63%). Based of environmental parameters the percentage similarity of between sample site I and III was of 99.030%. Key words :Jerajang Coastal Water,Electric Steam Power Plant, Diatom