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The Relationship among Dissolved Inorganic Phosphate, Particulate Inorganic Phosphate, and Chlorophyll-a in Different Seasons in the Coastal Seas of Semarang and Jepara

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Maslukah L. , Zainuri M. , Wirasatriya A. , Maisyarah S.

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tom Vol. 21, nr 3

135--142

EN

The speciation of particulate inorganic phosphate (PIP) in waters is still rarely studied, unlike the dissolved inorganic phosphate (DIP) which is often used in the assessment of the water quality parameters and their effect on the presence of chlorophyll a. This research aimed at determinig the relationship between DIP and PIP and its effect on the concentration of chlorophyll-a. This research was conducted in the waters of Semarang and Jepara, in different seasons (Rainy and dry). Speciation from PIP was obtained through an extraction process using 1 M HCL and continued with phosphate analysis using the molybdenum blue method, as in the DIP analysis. The linear model was used to find an equation and determine the variables that affect chlorophyll a. Our results showed that the distribution patterns of DIP, PIP and Chlorophyll-a have different patterns in the two study areas and different seasons. The concentration of DIP is always high in the Semarang waters, and is followed by a high chlorophyll-a response. A different pattern was found in the Jepara waters, where the chlorophyll-a response is high in the east monsoon. The relationship of Chl-a to DIP was very significant in the west season in the waters of Semarang and the Jepara region in the east season (p < 0.05). The relationship of chlorophyll a to DIP in the Semarang and Jepara waters produced an equation, Chl a = -56.565 + 76.672 (DIP) with a coefficient of determination R2 = 0.478, at a significant level (p) = 0.004 and Chl a = -25.844 + 68.827 (DIP) with value of R2 = 0.421 at a significance level of p = 0.007, respectively.

2

The Chlorophyll-a Response of Phytoplankton to Ratio N/P in Different Coastal Waters

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Maslukah L. , Handoyo G. , Wulandari S. Y. , Sihite C. B. , Sarjito

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tom Vol. 24, iss. 9

121--129

EN

Phytoplankton growth is influenced by the presence of nutrients N (nitrogen) and P (phosphor). Each region has a specific N/P ratio, due to the influence of anthropogenic inputs. This study aimed to assess the response of phytoplankton chlorophyll-a (Chl-a) biomass due to differences in N/P ratio by the influence of river flow in the north coast of Java; Jobokuto Bay (Jepara), the coastal waters of Semarang and the front of the Cisadane river. N-nutrients were analyzed in the form of N-NO3 (nitrate), and N-NH4+ (ammonium ions), and orthophosphate ions (P-PO42-). Nutrient analysis was spectrometric, using the reduction methods (nitrate), ammonium (indophenolblue), and phosphate (molybdenum-blue). Test for site differences using Kruskall-Wallis, followed by a posthoc test. The results showed that Semarang waters had a lower N/P (Stoichiometric) ratio than Jepara and Cisadane, which can be used to predict that P nutrient input is higher than N. This high P input impacts microalgal development (chlorophyll-a). In addition, we also found Semarang waters to have higher speciation of inorganic N in the form of ammonium, which is one of the drivers of eutrophication in these waters. The use of a ratio of N/P is very important in estimating the eutrophication process and can be used to estimate the dominance of nutrients entering the water due to anthropogenic activities in the upstream area.

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Fractionation and bioavailability of phosphorus and its relation to chlorophyll-a at the coastal area of Semarang city

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Maslukah L. , Wirasatriya A. , Widada S. , Ismunarti D. H. , Yusuf M. , Salma U. , Zainuri M.

Ecological Chemistry and Engineering. S

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2022

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tom Vol. 29, nr 2

183--197

EN

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.

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Comparative Study on the Microplastics Abundance and Characteristics in Marine Protected Area in Karimunjawa National Park, Indonesia

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Widiaratih R. , Marganita D. , Suryoputro A. A. D. , Handoyo G. , Maslukah L. , Satriadi A. , Satya E. D.

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tom Vol. 25, nr 4

119--130

EN

Microplastics (MPs) are discovered in various places even encroaching on marine protected areas (MPA). The aim of this research is to investigate the occurrences of MPs pollutant in MPA and non-MPA in Karimunjawa National Park (KNP). The results showed that MPs from sea surface water were higher in MPA than non-MPA with range as 47.89–106.20 items/L, dominated by fragment, 1–50 µm size, black color and HDPE, LDPE, PP, Nylon, PVC, ABS, and PET in polymer types. It induced since it supplied from it surrounding, specifically the south of MPA, whereas there have been cottage constructions generating many marine debris. These findings indicate that occurrence of MPs still dominantly influenced from anthropogenic activity. However, the hydrodynamic and MPs characteristic as well play an important role in MPs distributions.