The mangrove ecosystems in East Java are widely exploited and converted for other land. Mangrove forests help decrease carbon dioxide concentration, are very efficient carbon sinks and store them in large quantities in biomass and sediments for a long time. This paper tries to understand the causes and effects of mangroves ecosystem damage on carbon stocks and absorption, with East Java, Indonesia as a case study. The Driver, Pressure, State, Impact and Response (DPSIR) framework, Analytic Hierarchy Process (AHP), and Partial Least Squares (PLS) used to identify and solve these problems. The result shows that the destruction of mangrove forests in East Java has occurred due to land conversion intensification. Accordingly, the mangroves’ average carbon sequestration and storage in East Java can be classified as moderate to low. Illegal logging is the leading cause, so there needs to be a clear policy that involves the government and the community. This result suggests that forming a strategy to prevent illegal logging and increase carbon sequestration and storage must be carried out, and community engagement in decision-making processes to protect and manage the mangrove forests.

The aim of this study is to investigate patterns of landscape changes in small islands as exemplified by Gili Matra Islands, Lombok, Indonesia. Satellite imagery, hard infrastructures data and tourism spot were used to observe patterns of land use/land cover (LU/LC) by using overlay method in order to find suitable indicators for assessing landscape changes in the case study. The results showed that the changes tend to grow based on the closeness to the paths, port, coast line, public service, rural center, commercial areas, settlement areas, tourism accommodation, tourism center areas, and tourism spots and keep away landfill area.

A study of nutrients, underwater light dynamics, and their correlation with phytoplankton biomass was conducted in the tropical estuary of Jakarta Bay, Indonesia, in the dry season during the period from 2001 to 2019. This study analyzed the spatial and temporal dynamics of phytoplankton biomass and its correlation with phytoplankton biomass. There was significant increase in nutrient concentration in Jakarta Bay, with annual means of 27.97 µM dissolved inorganic nitrogen (DIN) and 11.31 µM phosphates in 2001, increasing to 88.99 µM DIN and 25.92 µM phosphates in 2019. Increased mean nutrient concentrations were accompanied by increased mean phytoplankton biomass, from 15.81 µg Chl-a L⁻¹ in 2001 to 21.31 µg Chl-a L⁻¹ in 2019. The eutrophication status of Jakarta Bay waters was calculated using the Tropical Index for Marine Systems eutrophication index, which showed increased areas of hyper-eutrophic and eutrophic zones, while the mesotrophic area decreased. The hyper-eutrophic zone dominated the areas around river mouths and the inner part of the bay, while eutrophic status was observed in the middle part of the bay and mesotrophic status was found in the outer part of the bay. The area of hyper-eutrophic water increased 1.5-fold, from 75.1 km² in 2001 to 114.0 km² in 2019. Increasing eutrophication of the bay has had negative ecological consequences including algal blooms, hypoxic conditions, and mass mortality of marine biota, and it urgently requires remediation.