Nutrient amount mangrove ecosystem in Bedono, Sayung district, Demak regency

Abstract

The mangrove ecosystem in Bedono in some places is damage, which is caused by the erotion of the ocean current and wave. In the beginning it was the residential areas which were abandoned by residents some decade ago. These area store the organic and mineral material. The research aimed to found sediment/soil texture shore and to find out the contents of organic material (Carbon), Nitrogen, Phosphate and Pothasium/Kalium in the sediment and water in the mangrove areas. These research was conducted from February-June 2017. This research used descriptive method. The samples were taken by purposive sampling, include 3 station are Morosari (A), Tambaksari (B) and Senik/Rejosari (C). Each station was determined by three places sampling systematically. The sediment sampling were taken at a depth 10 cm and the sampling water were taken in the some places. The analysis of sediment/soil texture were carried out in the Soil Laboratory Civil Engineering Faculty, University of Diponegoro in Semarang and analysis soil and water were carried out in the Soil Laboratory, Agriculture Faculty, Gadjah Mada University in Yogyakarta. The result of the research showed that soil texture in Morosari including the kind of dusty loam texture. In Tambaksari including the kind of sandy loam to dusty loam texture., in Senik/Rejosari including sandy loam texture. The result of the research showed that the nutrient contents at the sediment in the Bedono village indicated the organic material 6,21 % (low), organic carbon 3,75 %, the dissolved organic carbon 0,09 % (low), the total nitrogen 0,20 %, and the dissolved nitrogen 8,66 ppm (low), the available phosphate at the sediment 24,73 ppm (medium) and the dissolved phosphate 0,095 ppm only the June, in February and April undetect. potassium/kalium content at the sediment was 3,75 me/100 gram (low) and the dissolved pottasium/kalium in the water was 66,93 ppm (medium). Mangrove genera in Bedono are Avicennia and Rhizophora it was associated with same mollusc species, and the dominant macrobenthos in Bedono are Cassidula sulculosa and Natica fasciata.