Coastal Dynamic, Nitrate (NO3-) Phosphate (PO4-) and Phytoplankton Abundance at Morodemak North Java Sea Indonesia

Coastal dynamic of North Java sea was the influence of the west and east monsoon as well as interseasonal effect during April-June and October-December. Espescialy to coastal current patern and to nitrate and phosphate variation and ultimately to phytoplankton. Study area focused at 110°52'03.72''E 110°54'68'' E and 06°80.4'75''S 06°82'72.22''S. The study was conducted for 1 mont in September 2014. Location of this research at Morodemak waters of North Java Sea. Aim of study was to built current spatial model, measure insitu nitrate and phosphate variation and phytoplankton abundance. Coastal current spatial modelling was done using SMS-v8.1 and sampling site based to purposive sampling represetative to the estuary and coastal system. Spatial modelling using Arc.GIS 10 software. The study revealed that nitrate concentration ranged at 0.60 2.0 mg/l, phosphate 0.04 0.24 mg/l and current speed 0.0003 0.0033 m/sec to southeast direction. About 22 genera of phytoplankton were found, with moderate dominancy of Baccilariophyceae, Dinophyceae and most dominance of Rhizosolenia. Most abundance of phytoplankton was at the mouth of the river or the estuary with 28,090,000 cell/m3. Lowest abundance at offshore coastal site with 17,060,000 cell/m3. The highest diversity index (H’) was 1.606 at the estuary and the lowest was 0.8730 at coastal offshore. Keywords-Coastal current, nitrate, phosphate, phytoplankton, North-Java Sea