The World's First 3D Simulations Reveal the Physics of Superluminous Supernovae
Author(s)Chin-Chang Hung & Kamal Ranatunga
Dr. Chin-Chang Hung is currently a distinguished Professor in the Department of Oceanography at NSYSU. His research interests are to understand mechanisms affecting marine carbon cycling in the ocean and to study environmental changes affecting nutrient dynamics and plankton community composition in the ocean. Dr. Kamal Ranatunga is currently a director of TS/ECSTIC at the Department of Zoology (Aquatic Resources Management program) with research interests in marine ecology, coastal pollution and coastal resources management.
Academy/University/OrganizationNational Sun Yat-sen University
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The “Taiwan and Sri Lanka Environmental Change Sciences and Technology Innovation Center (TS/ECSTIC)” was established at the University of Sri Jayewardenepura (Sri Lanka) in 2019 with the aim of achieving the goal of academic cooperation between the two nations, and of offering research results for adaptive solutions to global environmental change. It was set up to strengthen the bilateral scientific research and diplomatic relations between the two countries. TS/ECSTIC’s team is involved in identifying and looking for solutions to the coral bleaching issues, fish kill events and low productivity in the lagoon and coastal waters of Sri Lanka. They selected Negombo Lagoon, which serves important functions including fishing, tourism and a carbon sink, as a start for this research. A preliminary survey showed that higher total suspended matter, organic matter and domestic waste can be transported to coastal waters through the heavy rainfall during the wet season, with significant impacts on the marine ecosystem. Besides, low dissolved oxygen values near the hotels beside the lagoon strongly support the fish kill events which occurred in a dry season, as reported by Dahanayaka et al. (2012).
When one comes to Sri Lanka, one’s first impression is the famous Ceylon Tea. However, the land and marine resources are also quite rich. Crabs and shrimps are larger than palm-size, and can be seen everywhere in Sri Lanka's local fish markets. Tens of thousands of tourists visit this island for its unique landscape every year. As Taiwan and Sri Lanka are small island nations, we found that the marine bio-resources and marine ecosystems in both countries have been affected by global warming, ocean acidification, and environmental change in recent years. The national authorities have noticed and put efforts into solving these problems. Thus, with the assistance of the Ministry of Science and Technology, the “Taiwan and Sri Lanka Environmental Change Sciences and Technology Innovation Center (TS/ECSTIC)” was established in USJP (University of Sri Jayewardenepura, Sri Lanka) in February 2019. By the establishment and operation of TS/ECSTIC with the goal of academic cooperation between the two nations, it is hoped that research results for adaptive solutions to global environmental change can be offered.
Taiwan and Sri Lanka Environmental Change Sciences and Technology Innovation Center unveiled at the University of Sri Jayawardenepura, Sri Lanka
Coral bleaching has been reported around the country, including off the west coast of Sri Lanka, but the factors that influence it are still poorly understood. Additionally, fish kill events have also been reported in the Negombo Lagoon as well as in other lagoons from time to time, but it is difficult to distinguish the causative factors due to the lack of long-term information such as seawater temperature, total suspended matter and nutrient distribution in the coastal region. Professor Hung’s team aims to investigate this issue, and chose Negombo Lagoon as a start for this research since this lagoon serves important functions including fishing, tourism and a carbon sink. It receives a huge load of nutrients and organic matter from the heavily populated and industrialized catchment area, and hence the water quality is degraded. Consequently, the high content of nutrients and organic matter in freshwater flows will eventually be drained into the nearshore coastal region, causing threats to the marine ecosystems off Negombo Lagoon. Nonetheless, nutrient concentrations and hydrography in Negombo also affect the carbon sequestration function of the mangrove ecosystems in the Negombo estuary. Thus, the team carried out a survey to investigate the hydrodynamics and nutrient content in the waters of the Negombo Lagoon and adjacent water bodies that bring fresh water into the lagoon.
An instrument in the Negombo lagoon for continuous monitoring of temperature, salinity, dissolved oxygen, pCO2 and pH.
A preliminary survey was conducted to investigate the hydrography, dissolved oxygen (DO), total suspended matter (TSM), nutrients, chlorophyll-a (Chl-a), particulate organic carbon (POC) and particulate nitrogen (PN) content in the Negombo Lagoon and the adjacent coastal waters in Sri Lanka during the dry season and wet season. The results showed that very low DO values were observed in the upper part of the lagoon. In the dry season, phosphorus is likely a limiting nutrient based on higher N/P ratios, but nitrogen in the outlet water of the west coast of Negombo Lagoon is likely a limiting factor with lower N/P ratios. In the wet season, phosphorus is likely a limiting nutrient in both regions. It suggests that the rainfall brings nitrogenous sewage, fertilizer residue, and organic nitrogen discharge into the coastal waters from the lagoon. It shows that higher TSM, organic matter and/or domestic waste can be transported to coastal waters during the wet season, with significant impacts on the marine ecosystem. Besides, low DO values near the hotel beside the lagoon strongly support the fish kill events which occurred in a dry season, as reported by Dahanayaka et al. (2012). We postulate that the low oxygen water might be due to domestic waste and waste from residents and/or hotels directly entering the lagoon, resulting in an almost hypoxic environment. Dahanayaka et al. (2012) suggested that polluted water could be coupled with disturbance of water circulation because narrowing of the outlet channels can mitigate the flow rate and increase high algal growth resulting in sudden fish kills. It is worth investigating the factors responsible for eutrophication and fish kills in detail.
As mentioned above, the investigation shows that huge fluxes of nutrients and TSM can discharge into the lagoon and coastal region during heavy rainfall. This could be a potential threat to the marine ecosystems including coral reefs. Professor Hung’s view is that it is necessary to build a successive monitoring system for hydrography and TSM as well as intensive observations for nutrients and biogeochemical parameters in the future in order to address the issues of coral bleaching or fish kill events off the western coast of Sri Lanka.
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