Microalgae is a very potential to be developed biota Because of its abundant amount on earth. Research on microalgae and its application as pigment analysis, provides important information about chemical compounds such as carotenoids and chlorophyll roomates that can be developed into drugs. Microalgae such as Chlorella vulgaris, Nannochloropsis sp., Porphyridium cruentum and Spirulina platensis has known had carotenoid pigments and chlorophyll content, but the optimization of the production of pigment in microalgae life phase has not been known in detail. Chlorophyll content in microalgae in the logarithmic phase of Chlorella vulgaris 200-1500 mg/L, Nannochloropsis sp. 100-500 g/L, Porphyridium cruentum 500-800 g/L and Spirulina platensis 1000-3500 mg/L and for stationary phases microalgae Chlorella vulgaris 100-1000 mg/L, Nannochloropsis sp. 200-500 g/L, Porphyridium cruentum 900-2000 mg/L and Spirulina platensis 2000-6000 mg/L. While the carotenoid content of microalgae in the logarithmic phase of Chlorella vulgaris 10-40 g/L, Nannochloropsis sp. 10-60 g/L, Porphyridium cruentum 10-60 ug/L and Spirulina platensis 20-40 ug/L and for stationary phases microalgae Chlorella vulgaris 10-50 g/L, Nannochloropsis sp. 10-70 g/L, Porphyridium cruentum 70-130 ug/L and Spirulina platensis 20-1100 mg/L.

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Estuaries are coastal areas that have a fairly high fertility rate. This region can be said to be fertile because it is influenced by such physical factors as temperature, turbidity, light, and current as well as such chemical factors as salinity, dissolved oxygen, pH, and nutrient content. The estuary of the Banjar Kemuning River is a coastal area with a lot of human activities, and it is close to the mainland, causing the change in the nutrient content in the waters. The nutrient content in the waters is closely related to the phytoplankton abundance, as the higher the nutrient content in the waters, the greater the phytoplankton abundance and the chlorophyll-a content. The level of chlorophyll-a content in the waters can indirectly be used as an indicator of the phytoplankton abundance, which can determine the level of fertility of these waters. The purpose of this study was to determine the relationship between the phytoplankton abundance and the chlorophyll-a content in the estuary of the Banjar Kemuning River. This study is observational research with data analysis using linear regression, simple correlation (Pearson), and ANOVA. In addition, the data collection was carried out by purposive random sampling at predetermined points of stations. The results of this study indicated that the phytoplankton abundance and the chlorophyll-a content at the estuary of Banjar Kemuning River during different months were significantly different (P<0.05). The averaverage chlorophyll-a content during the study was 0.958 µg/L, 0.998 µg/L, and 1.167 µg/L. The conclusion was drawn that there is a difference between the phytoplankton abundance and the chlorophyll-a content each month and classified into high correlation.

Sedati is one of the Sidoarjo Regency's Coastal Areas, which has potential resources in capture fisheries. Many industries in Sedati have caused a decrease in the aquatic productivity and aquatic organism conditions, including gastropods. Gastropods are easy to find in various habitats, but their distribution is highly dependent on the habitat conditions such as physical, chemical and biological factors. Gastropods are sensitive to environmental changes and can withstand the environmental changes that are not too wide to be used as indicators of environmental pollution. This study aims to determine the structure of the gastropod community in the Sedati Waters. The research was performed using an observation method. The gastropod samples were taken using a dredge net, while the substrate samples were collected using Ekman grab. The gastropods found in Sedati Waters from October to December are nine species from 2 orders and six families. The species most commonly found in R. venosa, while the least is C. ventricosa. The abundance index of gastropods every month shows a marked difference between stations but not the other main parameters. The diversity index value was between 1.4846-2.0897. The evenness index value reached between 0.8284 and 0.9548. The dominance index ranged from 0.16 to 0.2299. The community structure of gastropods in the Sedati Waters, Sidoarjo, East Java shows a significant difference (p<0.05) between stations and belongs to the medium category.