Sebaran Horizontal Zat Hara di Perairan Lamalera, Nusa Tenggara Timur (Horizontal Distribution of Nutrients in the Waters Lamalera, East Nusa Tenggara)

Perairan Lamalera, Nusa Tenggara Timur merupakan perairan yang sangat penting karena kondisi oseanografinya yang dipengaruhi daratan, Laut Sawu, dan Samudera Hindia sehingga kaya akan sumberdaya laut. Penelitian oseanografi di perairan Lamalera, Nusa Tenggara Timur telah dilakukan pada bulan Juli 2011. Tujuan penelitian tersebut untuk mengkaji kualitas air ditinjau dari kandungan zat hara yang merupakan indikator kesuburan perairan serta faktor-faktor yang mempengaruhinya di perairan Lamalera, Nusa Tenggara Timur. Parameter yang diteliti meliputi fosfat, nitrat, dan silikat serta parameter kualitas air yaitu oksigen terlarut, dan keasaman (pH). Metode penelitian yang digunakan adalah pengambilan air laut dari lapisan permukaan (5 m), termoklin (15-150 m)) dan dibawah termoklin (100-300 m) pada 19 stasiun penelitian. Kadar fosfat, nitrat, dan silikat dianalisis menurut metode Strickland dan Parsons. Kadar oksigen terlarut diukur dengan menggunakan metode Winkler. Derajat keasaman (pH) diukur dengan pH meter Cyber Scan 300. Hasil yang diperoleh menunjukkan bahwa kadar zat hara pada umumnya lebih tinggi di sebelah selatan perairan ini. Kadar fosfat berkisar 0,53–5,93 μg A/l; nitrat 0,34–28,31 μg A/l, dan silikat 0,69–44,60 μg A/l. Kadar oksigen terlarut berkisar 2,30–4,90 ml/l, dan nilai pH 7,85–8,21. Parameter yang diteliti di perairan Lamalera, Nusa Tenggara Timur masih baik untuk kehidupan berbagai biota mengacu pada Baku Mutu yang telah ditetapkan oleh Kementerian Negara Lingkungan Hidup (KMNLH). Kata kunci: Kualitas air, fosfat, nitrat, silikat, Perairan Lamalera. Lamalera Waters, East Nusa Tenggara is one of the waters are very important because the condition of the affected land, Sawu Sea, and Indian Ocean, so rich in marine resources. Oceanographic research in the Lamalera Waters, East Nusa Tenggara have been carried out in July 2011. The research objective was to assess water quality in terms of the nutrients content, which is an indicator of fertility waters, and the factors influencing it in the Lamalera Waters, East Nusa Tenggara. The parameters studied include phosphate, nitrate, silicate, and water quality parameters of dissolved oxygen and acidity (pH). The research method used is by taking seawater from a layer of surface (5 m), thermocline (15-150 m), and below the thermocline (100-300 m) at 19 research stations. Levels of phosphate, nitrate, and silicate were analyzed according to the method of Strickland and Parsons. Dissolved oxygen levels were measured by using the method of Winkler. The degree of acidity (pH) was measured with pH meter Cyber Scan 300. The results obtained indicate that nutrient levels are generally higher in southern waters. Phosphate levels ranged from 0.53 to 5.93 ug A/l nitrate 0.34-28.31 ug A/l, and silicate 0.69-44.60 ug A/l. Dissolved oxygen levels ranged from 2.30 to 4.90 ml/l, and pH values from 7.85 to 8.21. Parameters studied in the Lamalera Waters, East Nusa Tenggara is still good for the life of various biota refers to the Quality Standards set by the Ministry of Environment (KMNLH). Key words: water quality, phosphate, nitrate, silicate, Lamalera Waters