KETERKAITAN SPASIAL KUALITAS LINGKUNGAN DAN KEBERADAAN FITOPLANKTON BERPOTENSI HABs PADA TAMBAK EKSTENSIF DI KECAMATAN LOSARI KABUPATEN CIREBON, JAWA BARAT
Authors: Tarunamulia Tarunamulia , Kamariah Kamariah , Mustafa Akhmad 
Published: December 2016

Harmful Algal Blooms (HABs) dapat memberikan dampak negatif secara ekologis, ekonomis dan kesehatan.  Kejadian dapat bervariasi menurut faktor lingkungan lokal pemicu serta kemampuan adaptasi spesies.  Penelitian ini bertujuan untuk mengetahui keterkaitan antara karakteristik kualitas lingkungan dengan keberadaan fitoplankton berpotensi HABs pada tambak ekstensif di Kecamatan Losari Kabupaten Cirebon, Jawa Barat.  Sebanyak masing-masing 45 contoh air dan tanah diambil pada total luas petakan tambak ±2300 ha dengan metode transek yang dimodifikasi. Peubah kualitas air yang diukur meliputi; Total Amonia Nitrogen (TAN), Nitrit (NO2-N), Nitrat (NO3-N), Fosfat (PO4-P), Bahan Organik Total (BOT) dan Plankton.  Sedangkan peubah kualitas tanah tambak meliputi pH, total nitrogen (NTOT), fosfat (PO4-P) dan BOT. Analisis keterkaitan kualitas lingkungan dengan keberadaan fitoplankton berpotensi HABs dilakukan dengan BIO-ENV analysis, Cluster analysis, dan analisis spasial dengan software PRIMER 5.0 dan ArcGIS 10.0.  Dari  23 spesies yang diidentifikasi terdapat 5 spesies (21%) yang potensial sebagai HABs meliputi Prorocentrum sp, Ceratium sp, Gymnodinium sp, Thalassiosira sp dan Nitzchia sp.   Prorocentrum sp ditemukan pada 21 stasiun  dari total 45 stasiun dengan kepadatan tertinggi (508 ind/L). Hasil analisis selanjutnya menunjukkan bahwa distribusi spasial spesies berkaitan erat dengan distribusi nilai TAN dan BOT air serta nilai N-Total tanah. Jika tidak ada upaya pengelolaan dan mitigasi sehubungan keberadaan HABs tersebut maka dikhawatirkan dapat mempengaruhi produktivitas dan keberlanjutan kegiatan budidaya di lokasi penelitian.Harmful Algal Blooms (HABs) can cause serious negative ecological, economical and human health impacts. The occurrence of HABs may vary according to local environmental factors and the adaptability level of the causative species. This study aims to determine the relationship between environmental quality and the presence of causative phytoplankton species of HABs at extensive brackishwater aquaculture ponds located in Losari District, Cirebon Regency, and West Java Province. The sampling method followed a modified transect method by which a total of 45 each water and soil samples were taken from pond units, covering the total area of about 2300 ha. Water quality parameters comprised total ammonia nitrogen (TAN), nitrite, nitrate, phosphate and total organic matter (TOM). Whilst the pond soil quality variables included pH, total nitrogen (NTOT), phosphate and TOM. Spatial relationship between environmental quality and the presence of potentially causative phytoplankton species of HABs conducted through BIO-ENV analysis, cluster analysis and spatial analysis with the help of software PRIMER 5.0 and ArcGIS 10. Of the total 23 identified phytoplankton species, 5 species (21%) were classified as potentially causative sepecies of HABs including Prorocentrum sp, Ceratium sp, Gymnodinium sp, Thalassiosira sp and Nitzchia sp.  Prorocentrum sp was discovered in 21 stations of a total of 45 stations and accounted for the highest density (508 ind. / L). The results further indicated that the spatial distribution of the causative species is closely related to the distribution of values of TAN and TOM (water) and NTOT (soil).  Unless effective management and mitigation efforts are undertaken, the presence of the potentially causative species could affect the sustainability of aquaculture activities at the study sites.