<p><strong><em>Abstract.</em></strong><em> </em><em>The distribution of microplastic was studied in the Muara Badak districts Kutai Kartanegara regency in May 2015. Sediment samples were taken from four stations that represent residential, in mangrove, near the beach and away from residential areas. Sediment samples were taken using the pipe at a depth of 0-10 cm - 10-20 cm, then the observed and calculated abundance of microplastic. The results showed that the type microplastic found is a fragment, film and fiber. At Station 1 found fragments about 100.2-201.3 particle/kg, the film about 69.6-79.9 particles/kg and fiber  about 43.1-50.9 particles/kg, the stations 2 found of fragments about 146.5-238.8 particle/kg, the film about 53.2-81.9 particles/kg and fiber about 48.8-75.5 particles/kg, stations 3 found of fragments about 204.2-207.9 particles/kg, the film about 107.7-126.5 particle/kg and fiber about 26.1-39.9 particles/kg, station 4 found of fragments about 167.6-220 particle/kg, the film about 59.7-69.5 particle/ kg and fiber about 47.5-55.3 particles/kg. </em></p><p><strong><em>Keywords:</em></strong><em> Depth; Microplastic; Muara Badak; Sediment </em></p><p><em> </em></p><p><strong>Abstrak. </strong>Distribusi mikroplastik diteliti di Kecamatan Muara Badak Kabupaten Kutai Kartanegara pada bulan Mei 2015. Sampel sedimen diambil dari 4 stasiun yang mewakili pemukiman penduduk, dekat sungai, dekat pantai dan jauh dari pemukiman penduduk. Sampel sedimen diambil menggunakan pipa paralon pada kedalaman 0-10 cm – 10-20 cm, kemudian diamati dan dihitung kelimpahan mikroplastik. Hasil penelitian menunjukan bahwa jenis mikroplastik yang ditemukan adalah fragmen, film dan fiber. Pada stasiun 1 ditemukan fragmen berkisar 100,2-201,3 partikel/kg, film berkisar 69,6-79,9 partikel/kg dan fiber berkisar 43,1-50,9 partikel/kg, stasiun 2 ditemukan fragmen berkisar 146,5-238,8 partikel/kg, film berkisar 53,2-81,9 partikel/kg dan fiber berkisar 48,8-75,2 partikel/kg, stasiun 3 ditemukan fragmen berkisar 204,2-207,9 partikel/kg, film berkisar 107,7-126,5 partikel/kg dan fiber berkisar 26,1-39,9 partikel/kg, stasiun 4 ditemukan fragmen berkisar 167,6-220 partikel/kg, film berkisar  59,7-69,5partikel/kg dan fiber berkisar 47,5-55,3 partikel/kg.</p><p><strong>Kata kunci:</strong>  Kedalaman; Mikroplastik; Muara Badak; Sedimen</p>

Foraging strategies of dugongs in tropical areas are not yet well understood, and that is particularly true for grazing of fast-growing pioneer seagrass meadows in the intertidal zones. In this study, we investigated the driving factors affecting the number of grazing tracks in intertidal seagrass meadows caused by small herds of dugongs in Balikpapan Bay, Indonesia. We investigated seven intertidal seagrass meadows for which the dynamics of seagrass biomass, the ratio aboveground to belowground biomass, and the number of grazing tracks were recorded and measured based on monthly intervals over a year. Seagrass features showed a significant relationship with wind speed, precipitation, desiccation time, the distance of the grazing sward to a residential area, and fishing activity based on multiple (generalized) linear models. While the intertidal seagrass meadows consisted of 5 species in total, only Halodule pinifolia patches were grazed. Dugong feeding tracks were found in four of the seven sites. The strong variation in the number of tracks throughout the year was significantly affected by seagrass biomass of seagrass, location and wind speed. Our results show how the interplay of site conditions related to both shelter (wind speed) and food availability (seagrass biomass) determines its suitability for dugongs.

-Mangrove forest in Kutai National