Tropical Oceanographic Research Frontiers

Abundance and Characterization of Microplastics in Marketed Edible Salt from a Coastal Region of South Sumatra, Indonesia

2026-02-16T02:37:25+00:00

Microplastic contamination in food products has become an increasing environmental concern due to its widespread occurrence in marine and coastal ecosystems. Edible salt, a commonly consumed marine-derived product, has been recognized as a potential pathway of human exposure to microplastics. This study investigated the occurrence, abundance, and physical characteristics of microplastics in commercial table salt marketed in Sungsang Village, Banyuasin Regency, South Sumatra, Indonesia. Two locally marketed salt brands were analyzed using density separation, vacuum filtration, and microscopic examination. Microplastic particles were characterized according to their shape and size distribution. Microplastics were detected in all samples, with abundances ranging from 513 to 587 particles/kg. Fragments were the predominant particle type. Most particles were within the 50–300 μm size range, indicating that small-sized microplastics constituted a substantial proportion of the contamination. Based on average salt consumption rates, consumers may have been continuously exposed to microplastics through their daily consumption of salt. The presence of microplastics in all analyzed samples indicated that contamination could have occurred throughout the production and distribution chain of commercial salt. These findings contributed to the growing body of evidence regarding microplastic contamination in edible salt and highlighted the importance of routine monitoring and improved plastic waste management in coastal environments to reduce contamination of food products.

Monitoring Microplastics in Coastal Sediments of Eastern Mindanao Island, Philippines

2026-08-10T08:26:38+00:00

Microplastic contamination in coastal sediments represents a growing environmental concern, particularly in tropical regions where intensive coastal development and diverse anthropogenic activities contribute to plastic accumulation. However, spatially resolved information on microplastic abundance, morphology, and polymer composition remains limited in the coastal environments of Eastern Mindanao, Philippines. This study assessed the spatial distribution and characteristics of sediment-associated microplastics across five coastal locations representing fishing communities, estuarine environments, industrial-port activities, tourism, and aquaculture. Surface sediment samples were processed using density separation and chemical digestion, followed by microscopic characterisation and Fourier-transform infrared spectroscopy (FTIR) for polymer identification. Microplastics were detected at all sampling locations, with concentrations ranging from 76 ± 9 to 187 ± 22 particles/kg dry sediment. The highest concentration was observed in the industrial-port area, whereas the lowest occurred at the less populated tourist beach, indicating spatial heterogeneity in microplastic accumulation across different coastal settings. Fragments and fibers predominated across the sampling locations, suggesting contributions from the fragmentation of larger plastic debris and potentially fiber-releasing activities. FTIR analysis identified polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET), with PE and PP collectively accounting for more than 60% of the identified particles. Variations in microplastic abundance, morphology, color, and polymer composition indicated potential relationships with surrounding land-use characteristics, although specific pollution sources could not be conclusively established. The principal contribution of this study is the integrated characterisation of microplastic abundance, particle morphology, and polymer composition across contrasting coastal land-use settings in an understudied tropical island region. The findings establish a preliminary baseline for sediment microplastic contamination in Eastern Mindanao and provide evidence to inform targeted pollution monitoring, source investigations, and coastal waste-management strategies.

Blue Economy Development in ASEAN: Opportunities, Challenges, and Pathways Toward Ocean Sustainability

2026-08-10T08:31:43+00:00

The blue economy has emerged as a strategic framework for reconciling ocean-based economic development with marine ecosystem conservation and social well-being, particularly in maritime regions such as Southeast Asia. As one of the world’s most ocean-dependent regions, the Association of Southeast Asian Nations (ASEAN) possesses extensive marine resources that support fisheries, marine tourism, shipping, offshore energy, and emerging marine biotechnology industries. This review critically synthesizes the development, governance, challenges, and future prospects of the blue economy across the ten ASEAN member states. A total of 40 peer-reviewed journal articles published between 2010 and 2024 were systematically reviewed and organized into four thematic areas: (i) the sectoral composition and economic contribution of blue economy activities; (ii) policy, institutional, and governance frameworks; (iii) environmental and socioeconomic constraints; and (iv) emerging pathways toward sustainable and inclusive ocean-based development. The synthesis indicates that ASEAN’s ocean-based sectors collectively generate an estimated USD 360–380 billion annually, demonstrating their substantial contribution to regional economies. However, their long-term sustainability remains constrained by fragmented governance, marine ecosystem degradation, unsustainable resource exploitation, uneven institutional capacity, and inequitable distribution of economic benefits. Significant differences among member states further highlight the need for context-specific national strategies supported by stronger regional coordination. Future blue economy development should prioritize integrated ocean governance, sustainable blue finance, technological innovation and transfer, ecosystem-based management, and meaningful participation of coastal communities. Strengthening these mechanisms would enable ASEAN to move beyond sector-driven ocean exploitation toward a more resilient, inclusive, and environmentally sustainable blue economy while accelerating progress toward Sustainable Development Goal 14 (SDG 14: Life Below Water) and the broader 2030 Agenda.

Coastal and Island System Dynamics in the Philippines: A Review of Mangrove, Coral Reef and Seagrass Ecosystem Processes, Coastal Erosion and Habitat Restoration Approaches

2026-10-28T23:58:48+00:00

The Philippine archipelago lies at the centre of global marine shore fish biodiversity and supports extensive mangrove forests, coral reefs and seagrass meadows that sustain coastal livelihoods, food security and shoreline protection. These ecosystems are under mounting pressure from aquaculture conversion, siltation, destructive fishing, coastal development, land subsidence and increasingly intense tropical cyclones. This review synthesises peer-reviewed literature on (i) the ecological processes that govern mangrove, coral reef and seagrass dynamics in the Philippines, (ii) the drivers and consequences of coastal erosion and hazard exposure, and (iii) the effectiveness of habitat restoration approaches. Philippine mangrove cover has declined substantially over the past century, largely through conversion to brackishwater fishponds, and long-term survival of planted mangroves has often been low because of inappropriate species and site selection. Philippine coral reefs have lost about a third of their hard coral cover within a decade, while seagrass species richness declines sharply under siltation and aquaculture effluent. Healthy reefs and mangroves substantially attenuate wave energy, yet their protective role is undermined by degradation, subsidence and maladaptive hard engineering. Restoration has advanced from monospecific mangrove planting and coral gardening towards hydrology-based mangrove rehabilitation, larval enhancement of corals and seascape-scale planning. However, restoration remains constrained by scale, limited monitoring and weak institutional integration. We propose a research and management agenda that couples ecosystem process knowledge with nature-based coastal protection, long-term monitoring and governance reform.

Plankton Ecology in the Philippines: Diversity, Dynamics, and Ecological Significance Across Tropical Marine and Freshwater Ecosystems

2026-08-10T08:29:27+00:00

Plankton communities in the Philippines occupy a critical ecological position in one of the world's most biologically diverse marine regions. Situated within the Coral Triangle and traversed by the Western Pacific Warm Pool, Philippine waters support extraordinary phytoplankton and zooplankton assemblages that regulate primary production, mediate carbon fluxes, and sustain the productivity of pelagic and coastal fisheries. Yet these communities are shaped by complex interactions among the Southwest and Northeast Monsoons, seasonal upwelling, El Niño–Southern Oscillation (ENSO) events, eutrophication, and the proliferation of harmful algal blooms (HABs), particularly Pyrodinium bahamense var. compressum causing paralytic shellfish poisoning across coastal provinces. This review synthesizes published knowledge on phytoplankton diversity, zooplankton assemblage structure, HAB ecology, nutrient–plankton interactions, and the roles of plankton in biogeochemical cycles within Philippine marine and freshwater ecosystems. We further evaluate the impacts of eutrophication in enclosed bays such as Manila Bay and Laguna de Bay, coastal upwelling dynamics in the Visayas and Mindanao Seas, meroplankton contributions to larval connectivity, and emerging threats from climate change and land-based pollution. Knowledge gaps, monitoring priorities, and research directions including molecular approaches, autonomous sensing, and citizen science are identified. Integrative and long-term ecological research on Philippine plankton is urgently needed to support evidence-based marine spatial planning, fisheries management, and coastal conservation policy.