Estimation of Chlorophyll a Phytoplankton in the Coastal Waters of Semarang and Jepara for Monitoring the Eutrophication Process using MODIS-Aqua Imagery and Conventional Methods

Abstract

This study investigates the concentration of chlorophyll-a (chl-a) using the data of field observation and MODIS-Aqua imagery. The field observation data were retrieved by using a conventional method and processed using spectrometric analysis. This study covers the coastal and near land areas which have different levels of anthropogenic activity. The results showed that the coastal waters of Semarang with a high level of anthropogenic activity persistently show a concentration of chlorophyll a (chl-a) twice as large as Jepara coastal waters. This comparison value is obtained based on imagery and field data. Meanwhile, the ratio of chl-a field data in each region shows a value of ±5 times greater than the MODIS data. Field observation data shows a higher value than the MODIS-Aqua imagery data. The use of imagery data can be employed as a method of monitoring the eutrophication process on the coast. On the basis of the chlorophyll a classification and field observations, the coastal water of Semarang are classified as eutropic waters and Jepara is categorized as mesotropic category. The classification results will be different if monitoring is carried out using the image data with a location far from the mainland, the Semarang waters are included in the mesotropic category (> 2 mg•m-3) and Jepara is included in the oligotropic water category (< 2 mg•m-3).

Study Case: Productivity of Catched Fish in Locations around the Construction of Coal Power Plant, Jepara Indonesia

“…Based on Jepara Regency Regional Regulation Number 2 of 2011 concerning Jepara Regency Spatial Planning 2011-2031 article 14 paragraph (1-b) states that the plan to build Tanjung Jati coal-fired power plant units 5-6 in Jepara Regency is in accordance with the Jepara spatial plan [17] and this location is not included in the main fishing area for local fishermen [18] The area of the main fishing activity (fishing ground) in an area is strongly influenced by the amount of feed that supports fish life and its ecosystem. The existence of distribution of chlorophyll-a as a source of nutrition which is a source of feed can be an indication of the abundance of fish feed sources [19].…”

Sebaran Fosfat terhadap Konsentrasi Klorofil-a di Perairan Kota Pekalongan

“…Fosfor di perairan dapat berupa partikel anorganik, contohnya dalam bentuk mineral. Fosfat dapat ditemukan dalam bentuk terlarut dan terdeposisi ke dalam pori sedimen melalui proses adsorpsi (Maslukah et al, 2021(Maslukah et al, , 2022. Fosfat memegang peranan penting dalam mengubah energi dalam proses fotosintesis yang dilakukan oleh fitoplankton.…”

“…Namun yang langsung mempengaruhi pertumbuhan fitoplankton (klorofil-a) adalah dalam bentuk anorganik terlarut, yaitu dalam bentuk ion fosfat. Hal ini dikatakan pula oleh Sutamihardja et al (2018), serta Maslukah et al, (2020Maslukah et al, ( , 2021Maslukah et al, ( , 2022 bahwa nilai fosfat yang mengalami peningkatan disebabkan oleh badan air yang menerima masukan beban pencemar dan kemudian terakumulasi, salah satunya adalah dari limbah domestik. Kadar fosfat dalam suatu badan perairan dapat mengalami penurunan ketika kondisi pasang yang disebabkan oleh faktor arus dan pasang surut.…”

The Interaction of Chlorophyll-a and Total Suspended Matter along the Western Semarang Bay, Indonesia, Based on Measurement and Retrieval of Sentinel 3

“…Determination of the chlorophyll-a concentration in water analysis could be done by field measurements, laboratory measurements, or by monitoring the color of the sea using remote sensing data (Wang et al, 2017;Abbas et al, 2019;Maslukah et al, 2021). One of the remote sensing methods that have been developed to monitor the optical properties of water is using the Sentinel 3 satellite.…”

“…Satellite images MODIS and Landsat are also frequently used for chlorophyll-a monitoring. On the north coast of Java, research on chlorophylla using MODIS and Landsat has been done by some researchers, including Siregar Meanwhile, the results of the research by Maslukah et al, (2021) in Semarang waters indicated that the use of MODIS level 3 was not appropriate for monitoring chlorophyll-a in coastal areas or river estuaries. This is related to low spatial resolution (that is 4 km).…”