THE DISTRIBUTIONS OF N, P NUTRIENTS AND ITS RELATIONS WITH CHLOROPHYLL-a: CASE STUDY IN SERANG AND WISO ESTUARY, JEPARA, INDONESIA

摘要

The research was conducted in Jepara Waters to know the distribution of N, P nutrient and its relation to chlorophyll-a on two different estuary conditions. Upstream area of Wiso estuary, has a fairly dense population and Serang estuary has a large agricultural area. The watershed area (DAS) of Serang reaches 138.26 km2 and Wiso is only about 38.71 km2. N nutrient was determined as a nitrite ion using the sulphanilamide method after it was reduced using a reduction column (copper-cadmium). Soluble Pnutrient was determined as orthophosphate using ascorbic acid method. Chlorophyll-a concentration was measured by the APHA method. The average of N and P nutrient concentrations were found to be higher in Wiso estuary than in Serang estuary. The difference of N, P values at two locations reached 0.1 and 0.08. N nutrient had a wider range of values than P nutrient. The ratio of N/P in the estuary of Serang and Wiso were sequentially 3.24 and 2.83. The high ratio of nutrients in Serang estuary illustrates(he more abundant of N nutrient conditions. As a result, the concentration of chlorophyll-a became higher. In general, the patterns of nutrient and chlorophyll-a distribution at both sites show a high value in front of the mouth of the river at a location that has a depth of 2-3 meters and a salinity of 20-25%. The Wiso and Serang estuaries in Jepara waters are not included in the eutrophic category (<40 mg/m3).