This research examines the eutrophication process mainly by considering the chlorophyll-a concentration. A simple linear model was used to determine the correlation between Chlorophyll-a and dissolved inorganic phosphate (DIP). The research was carried out on river mouths in the north coast of Central Java. The results of the linear model show that the relationship between chlorophyll-a and DIP follows the logarithmic model with the log [Chloa] = 1.52 + 1.60 log [DIP], R 2 = 0.55. The model suggests that the high concentration of chlorophyll-a is related to dissolved inorganic phosphate concentrations. On the basis of the sufficient of conclusive evidence for these variables, the study sites with high stresses from several anthropogenic sources had higher chlorophyll-a than the sites that are relatively far from river mouths and lands.

Phosphorus (P) is an essential nutrient that can limit primary productivity in waters. Phosphorus has significant impact on the biogeochemical cycle in marine ecosystems. Surface sediments play an important role in the nutrient dynamics. Riverine input is sources of P to the ocean and sediment plays an important role as a source or sink of P in the coloumn of water. Phosphorous (P) availability is regarded as the most important factor for determining the water quality in coastal waters. However, not all of the P fractions can be released from the sediment. This study was conducted to identify the distribution of phosphorus (P) fractionation in the sediment surface of Jobokuto Bay. Samples were collected from ten locations. Percentage of sedimentary parameters such as sand, silt, clay, and organic carbon were analyzed to find out their relation with various P fractions. The sediment found was mostly sand at the station near to the coast and mud (silt and clay) at offshore stations. The results showed that Ca-P dominant (56.03%) and percentages of Fe-P, OP, and Ads-P were  23.43, 17.41, and 3.2% respectively. Terrestrial inputs and biological deposits cause Ca-P dominant. The bioavailability of P fractions were ranged from 34.45 to 56.1% of the total P (TP) content. The high concentrations of the Ads-P was found in the mud fraction and located at offshore stations. The order of abundance of the major forms of P in the surface sediments of Jobokuto bay is as follows: Ca-P > Fe-P > OP > Ads-P

The research aims to determine the trading volumes of retail state sukuk that are thought to be influenced by macroeconomics through inflation indicators and the rupiah/USD exchange rate as well as retail yield sukuk itself. This research uses multiple regression methods with retail state sukuk SR-007 series as research objects. The results of the study in partial inflation and yield were positively significant as well as the significant negative exchange rates on the trading volumes of the retail state sukuk SR-007 series. Simultaneously inflation, the exchange rate and the yield of retail sukuk have a significant influence on the trade volume of retail state Sukuk SR007 series. Regression Model shows R-squared adjusted value of 0.685428 This indicates inflation, the exchange rate and the yield of retail sukuk can explain the 68% of the dependent variable namely the trade Volume of retail state Sukuk series SR-007.

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Mud crabs (Scylla serrata and S. olivacea) are important fisheries resources, but their population in nature is decreasing due to anthropogenic activities, like the deforestation of mangrove forests. Hence, it is crucial to conserve this marine biota for future sustainable use and to conserve our marine biodiversity. Conducting studies on the biological interactions of mud crabs in mangrove habitats can be one of the future conservation approaches. Accordingly, an analysis of the functional relationships between Scylla spp. abundance and the respective mangrove habitat have to be carried out. The research was conducted in the mangrove ecosystem of Bee Jay Bakau Resort Probolinggo (BJBR). Data were collected using line transects and quadrant transects. The Associations between mangroves and mud crab habitat structures were analyzed using the Correspondence Analysis (CA) method. The results show that the relationship matrix between Scylla spp. and the structure of the mangrove habitat is centered on the F1 and F2 factorial axes (89.22%). S. serrata of all size classes were associated with dense mangroves (≥15 trees per 100m2) and high salinities (3-4 ppt), while S. olivacea has shown to be associated with rare to very dense mangrove systems. It indicates that S. olivacea tends to have a higher adaptation rate than S. serrata in this mangrove system. This study will provide information and recommendation for the conservation management of mud crabs and mangrove ecosystems to conserve marine biodiversity.