Irawan A, Supriharyono, Hutabarat J, Ambariyanto. 2018. Seagrass beds as the buffer zone for fish biodiversity in coastalwater of Bontang City, East Kalimantan, Indonesia. Biodiversitas 19: 1044-1053. The purpose of this study was to demonstrate theimportance of seagrass beds as a buffer zone for fish biodiversity in a coastal ecosystem. The sampling of seagrass and fish were done inseagrass beds associated with mangrove (ST1) and coral reef (ST2). Sampling period was executed from May 2011 to May 2017.Sampling was done on the lowest tide with a six-month interval. Seagrass sampling was carried out using line transect, and fishsampling was performed using set net (belat local name) operated by local fisherman. The results showed that seagrass beds at ST1composed of C. rotundata and E. acoroides and that at ST2 composed of C. rotundata, E. acoroides, H. pinifolia, H. minor and T.hemprichii. The total number of individual was 42574 divided into 112 fish species. There were 17 species (population: 15.18%)associated explicitly with ST1 and 39 species (population: 34.82%) specifically associated with ST2 while 56 fish species (population:50.0%) were prevalently spread in both stations. This research proved the existence of seagrass beds as a buffer zone for fishbiodiversity.

This study was aimed to analyze the prospects of development of the financial aspects of amplang processing and marketing channel of amplang processing business. The data was collected through a survey, completed by direct observation in the field and interviews with the respondents. The applied data analysis includes analysis of costs, revenues, income and business feasibility. The results showed the average revenue earned from amplang processing business is Rp. 7.040,000 per month or Rp. 70.400,000 per year, while the average cost of Rp. 4.623.167 per month or Rp. 46.238.333/year. The average income was found as much as Rp. 2.416.167/month or Rp. 24,161,667 / year. The value of the balance of revenue and cost (R/C) in the business of processing amplang is 1.54, which means that the amplang processing business is able to provide a gain of 1.54 of the cost. There are two pattern of marketing channel that were identified in the field, the first pattern is: amplang producer to retailer to consumer; and the second pattern is: amplang producer to consumer directly.

The research aimed to know the characteristic of horizontal distribution to the Physical-Chemical parameters of surface water in Eastern Site of Balikpapan coastal area. Result of research indicate that current pattern that happened tend to make a move northerly during the year to South. Hoizontal Distribution and temperature and TSS tend to increase to come near coast, while dissolved oxygen and salinity tend to increase while turbidity, conductivity, pH, phosphate and ammonia tend to flatten from coast till 4 mile to the sea. Horizontal Distribution Cu (0,001 - 0,014 mg / l) tend to increase to come near coast, Hg content tend to smaller 0,0005 mg / l and still under standard of sea water quality. Bottom of the eastern site of Balikpapan coastal tend to flat.

Seagrass sampling in this study was carried out using purposive sampling method at 4 research stations. The results of this study were found in 37 species of old seagrass leaves consisting of 9 classes, namely Bacillariophyceae, Mediophyceae, Coscinodiscophyceae, Euglenoidea, Cyanophyceae, Dinophyceae, Chorophyceae, Chrysophyta and Xexanauplia. While in young seagrass leaves there are 33 species consisting of 8 classes, namely Bacillariophyceae, Mediophyceae, Coscinodiscophyceae, Euglenoidea, Cyanophceae, Chrysophyta, Dinophyceae and Hexanauplia. The highest periphyton composition in old and young leaves was in the Bacillariophyceae class with a percentage of 67% on young leaves and 70.9% on old leaves. The diversity index value obtained showed moderate distribution criteria because the number of periphyton individuals found in old and young leaves was relatively the same.