KEANEKARAGAMAN BAKTERI PADA RUMPUT LAUT (Kappaphicus alvarezii) DI PERAIRAN PANTAI AMAL

Rumput laut (Kappaphycus alvarezii) merupakan komoditas penting perikanan yang memiliki nilai ekonomi cukup tinggi dan menjadi salah satu sumber devisa negara serta sumber pendapatan bagi masyarakat pesisir. Selain itu rumput laut banyak digunakan sebagai bahan dasar industri makanan, farmasi dan energi. Namun produksi rumput laut kota Tarakan pada tahun 2019 mengalami penurunan dari 159.468 ton menjadi 152.76 ton. Salah satu yang menyebabkan terjadinya penurunan produksi rumput laut adalah serangan penyakit  ice-ice yang disebabkan oleh bakteri. Tujuan dari penelitian untuk mengetahui keanekaragaman bakteri yang terdapat pada rumput laut di perairan Pantai Amal Tarakan. Isolasi bakteri dilakukan dengan menggunakan metode stread plat pada media TCBS (thiosulphate citrate bile salt sucrose) dan TSA (thiosulphate sucrosa agar). Sampel rumput laut dihaluskan lalu diambil sebanyak 5 gram kemudian dimasukkan ke dalam cawan petri yang berisi media TCBS dan TSA. Selanjutnya diinkubasi pada suhu 370C atau suhu ruangan selama 24 jam. Identifikasi bakteri dilakukan dengan mengacu pada buku Bergey’s Manual of Determinatif Bacteriology dan Manual For the Identification of Medical Bacteria dengan melakukan uji biokimia yang meliputi; Uji Pewarnaan Gram, Test Oksidase, Katalase, O/F (Oksidasi/Fermentasi), glukosa, motility, Produksi asam dari karbohidrat (D-Glukosa dan D-mannitol), lysin, urea, ornithin dan methil red. Hasil penelitian menunjukkan bahwa terdapat Keanekaragaman bakteri pada rumput laut (Kappaphycus alvarezii) di perairan Pantai Amal Tarakan diantaranya Corynebacterium, Acinetobacter, Bacillus, Pseudomonas dan Vibrio yang berpotensi menyebabkan penyakit ice-ice. Rekomendasi: Perlu menjaga keseimbangan lingkungan dengan memperhatikan parameter kualitas air, agar rumput laut tidak stres, sebab infeksi bakteri bersifat sekunder. Seaweed (Kappaphycus alvarezii) is an important fishery commodities that has a high economic value and is a source of foreign exchange and a source of income for coastal communities. In addition, seaweed is widely used as a basic material for the food, pharmaceutical and energy industries. However, Tarakan's seaweed production in 2019 decreased from 159.468 tons to 152.576 tons. One of the causes of a decrease in seaweed production is the attack of ice-ice disease caused by bacteria. The purpose of this study was to determine the diversity of bacteria found in seaweed in the waters of Amal Beach, Tarakan. Bacterial isolation was carried out using TCBS (thiosulphate citrate bile salt sucrosa) and TSA (thiosulphate sucrosa agar) media. Seaweed samples were mashed and then taken as much as 5 grams and then put into a petri dish containing TCBS and TSA media. Then incubated at 37°C or room temperature for 24 hours. Identification of bacteria is carried out by referring to the book Bergey's Manual of Determinative Bacteriology and Manual For the Identification of Medical Bacteria by conducting biochemical  tests which include; Gram stain test, oxidase test, catalase, O/F (Oxidation-Fermentation), glucose, motility, acid production from carbohydrates (D-glucose and D-mannitol), lysine, urea, ornithine and methyl red. The results showed that there was a diversity of bacteria in seaweed (Kappaphycus alvarezii) in the waters of the Tarakan Amal Coast including Corynebacterium, Acinetobacter, Bacillus, Pseudomonas and Vibrio which have the potential to cause ice-ice disease. Recommendation: It is necessary to maintain environmental balance by paying attention to water quality parameters, so that seaweed is not stressed, because bacterial infections are secondary.