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.

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.

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

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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.

The connectivity between seagrass and mangrove ecosystems has synergistic benefits of conserving the land-sea ecosystems of the small islands. The physicochemical properties of the two ecosystems lead to the success of the habitat of the interconnected zone. This study aimed to analyze the physicochemical factors in the mangrove and seagrass ecosystems on Pramuka Island and understand the factors influencing the phytoplankton production of small island coastal ecosystems. Sediment and water collection were carried out on Pramuka Island, Indonesia, to measure physicochemical parameters. Mangrove and seagrass ecosystems have the highest DO, temperature, and pH values. The phytoplankton counts showed significant variation between the sampling sites with a predominance of the class Cyanophyceae. The estimated primary productivity of chlorophyll-a indicated that its concentration was higher in mangroves than in seagrass. A similar trend was observed in nutrient loads and dissolved inorganic nitrogen. Results of the present study clearly showed that an increased concentration of dissolved inorganic nutrient influence the concentration of chlorophyll-a as an indicator of primary productivity. These findings will provide a preliminary analysis of the physicochemical conditions and productivity on Pramuka Island.

Bee Jay Bakau Resort (BJBR) is a mangrove ecotourism that has been rehabilitated from damaged mangrove areas. This rehabilitation have an impact on typical mangrove fauna such as Telescopium telescopium and Cerithidea obtusa. The present study was performed in December 2020. This study aims to analyze about abundance and growth pattern of gastropods T. telescopium and C. obtusa and the association with BJBR mangrove ecosystems. The sampling was determined using the purposive sampling technique and carried out at three stations based on the distinct locations using a 1mx1m transect. The association of gastropods and mangrove ecosystems was analyzed using Correspondence Analysis (C.A.). The results show that gastropods abundance ranged from 9 ind/m 2 to 84 individuals/m 2 . Overall, the growth pattern is allometric negative, which means the length growth is faster than the weight growth. The result of C.A. showed that there are three association groups of between gastropods and mangroves.

We investigate the distribution of various fractions phosphorus (P) in sediments at the coastal area of Semarang City. Samples were collected from thirteen locations at the Banjir Kanal Barat, port and Banjir Kanal Timur. Sedimentary parameters such as sand, silt, clay, and organic carbon were analysed in order to find out their relation with various P fractions. The sediment types are predominantly sandy and silty with low clay content. Among all fractions (loosely bound/Ads-P), bound calcium/Ca-P), iron bound/Fe-P), and organic fraction/OP), Ca-P fractions constitute the largest portion (71.2 %) followed by iron-bound (17.0 %), organic fraction (10.4 %) and loosely bound (1.4 %). The bioavailable P fractions range from 20.2 % to 42.0 % of the total P (TP) content with average 28.8 %. Relatively high Ads-P content is observed in offshore locations with comparatively high mud percentage as compared with the near-shore locations. The order of abundance of the main forms of P in the Semarang coastal surface sediments is as follows: Ca-P > Fe-P > OP > Ads-P. The concentration of this fraction causes the abundance of chlorophyll-a from 9.09 to 21.09 mg/m3.