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This study aims to review the occurrence of microplastics in some commercial aquatic organisms. Microplastics are small plastic particles with a diameter of less than 5 mm. Effluent, stormwater, agricultural, and surface runoff introduce microplastic to freshwater basins. Hydrodynamics and hydrology encompass microplastics. River flow speed can cause turbulence and riverbed instability, increasing microplastic concentrations. Fish, shellfish, and crustaceans ingest microplastics in proportion to their quantity in freshwater and marine environments. Human activities cause variations in the form, color, and size of microplastics in the biota. Animals absorb microplastics through trophic transfer. Increased microplastic residence time before ingestion promotes trophic transmission. Lower food concentration and aggregation enhance microplastic retention in zooplankton guts, increasing transmission to higher-trophic-level species. Most studies show that microplastics in biota are discovered in fish and crustacean intestines and bivalve tissues. Microplastic buildup can disrupt live organisms' growth and reproduction, induce oxidative stress, obstruct the digestive system, and damage the intestine. Microplastics may harm people's health if they eat contaminated seafood that contains them, but more research is needed.

POTENCY OF MARINE BACTERIA FOR BIOREMEDIATION. Marine bacteria have a high abundance on variation as well as the qenes, so it can be used in various aspects, including the prevention of marine pollution through bioremediation. High genetic variations provide a source of marine bacteria which has decompose-various substances capability. Various studies have been conducted to determine the potential of marine bacteria in degrading pollutants, including degradation of hydrocarbons, PAH, plastic, PCB and removal of heavy metal. Recombination through the insertion of the marine bacteria's gene coding enzyme has been also performed on indigenous actinomycetes on soil.

APPLICATION AND EFFECTIVITY OF BIOREMEDIATION TECHNIQUE FOR OIL CONTAMINATED COASTAL WATERS.Oil pollution is often occurs in Indonesian marine waters and it has a significant impact on ecological and economical aspects. Physical and chemical approaches are common to be used to combat this pollution. Bioremediation is a promising method using biological approach that not been used yet for oil spill cleanup in Indonesian coastal environment. The success stories were reported mostly from sub-tropic region. This technique is potential to be used in Indonesia due to tropical climates and enormous microbial resources in Indonesian marine waters. However, intensive research and field tests are still needed to develop an appropriate method for application in Indonesia. One of bioremediation technique limitations is the suitability for each polluted sites. This paper will discuss about the application and the effectivity of bioremediation technique in other countries and research development of this technique for coastal environment in Indonesia. PENDAHULUANPencemaran minyak di perairan laut dan pesisir, khususnya di Indonesia sudah sering kali terjadi, baik dalam skala besar maupun kecil (Rusdi, 2008;Sudrajad, 2006; Gunanto & Seo, 2010). Sumbernya beragam seperti buangan dari darat (sungai dan runoff perkotaan), buangan transportasi dan pencucian air ballast, rembesan alami, limbah industri, deposisi dari atmosfer, kilang minyak pantai, pengeboran minyak lepas pantai, kecelakaan transportasi laut dan kecelakaan pengeboran minyak lepas pantai (NRC, 2003).

<strong>Isolation of Crude Oil and Polycyclic Aromatic Hydrocarbon-Degrading Bacteria from Mangrove Sediments in Bintan.</strong> Bintan is known for its extensive mangrove areas, but it is prone to pollution from oil spills due to it is close to the international shipping lane. Indigenous bacteria plays important roles in bioremediation of oil spills in the natural environment. This research aims to explore indigenous bacteria from Bintan’s mangrove sediments which may have ability to degrade crude oil and polycyclic aromatic hydrocarbon (PAH). The mangrove sediment samples were taken in March 2018 from the sediments near four different mangrove plant species, i.e. <em>Rhizophora apiculata, Xylocarpus granatum, Ceriops tagal </em>and <em>Lumnitzera littorea</em>. Isolation of oil degrading bacteria was carried out using enrichment media supplemented with crude oil ALCO. A total of 45 strains of oil degrading bacteria were successfully isolated from the sediment samples. By using sublimation method, 13 bacterial isolates showed the ability to degrade various PAHs, including phenanthrene, acenaphthene, dibenzothiophene and fluorene. Sequencing analysis of 16s rRNA genes confirmed that the 13 isolated bacteria belong to the genera <em>Rhodococcus, Bacillus</em>, <em>Sphingopyxis</em>, <em>Rhizobium</em>, <em>Mycobacterium</em>, and <em>Gordonia</em>