Rumput laut Eucheuma cottoni merupakan jenis rumput laut yang paling populer untuk dibudidayakan di Perairan Liago. Pembudidayaan rumput laut tersebut mengalami kendala seperti parasit dan bakteri. Penelitian ini bertujuan untuk mengetahui jenis bakteri dan parasit yang ditemukan pada Eucheuma cottoni yang terserang penyakit ice-ice di Perairan Liago. Bakteri pada sampel rumput laut diidentifikasi karakteristik jenis berdasarkan uji presumtif dan uji biokimia. Jenis bakteri yang ditemukan pada rumput laut yang terserang penyakit ice-ice di perairan Liago Kabupaten Bulungan yaitu bakteri Vibrio sp dan Bacillus sp. Parasit yang ditemukan secara survey yaitu Lumut, kerang, ikan baronang, dan bulu halus. Pengamatan Uji biokimia meliputi Glukosa, OF dengan parafin, OF tanpa parafin, TSIA miring, TSIA tegak, TSIA gas, H2S, Motility, Indol, Orinthin. Kualitas air yang diamati dalam penelitian ini yaitu suhu, salinitas, pH, DO, fosfat dan nitrat.
Kata Kunci: Bakteri, Parasit, Eucheuma cottoni, Ice-ice, Uji Biokimia, Kualitas Air

Eucheuma cottoni seaweed is the most popular type of seaweed to be cultivated in Liago Waters. Seaweed cultivation is experiencing obstacles such as parasites and bacteria. This study aims to determine the types of bacteria and parasites found in Eucheuma cottoni which was attacked by ice-ice disease in Liago Waters. The bacteria in seaweed samples were identified based on presumptive and biochemical tests. The types of bacteria found in seaweed that was attacked by ice-ice disease in the waters of Liago, Bulungan Regency, were Vibrio sp and Bacillus sp. The parasites found in the survey were mosses, clams, baronang fish, and fluff. Observations Biochemical tests include Glucose, OF with paraffin, OF without paraffin, oblique TSIA, upright TSIA, gas TSIA, H2S, Motility, Indole, Orinthin. The water quality observed in this study were temperature, salinity, pH, DO, phosphate and nitrate. Keywords: Bacteria, Parasites, Eucheuma cottoni, Ice-ice, Biochemical Test, Water Quality