National Committee on Marine Sciences (NCMS)
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- Effect of the Intensified Sub‐Thermocline Eddy on strengthening the Mindanao undercurrent in 2019Azminuddin, Fuad; Lee, Jae Hak; Jeon, Dongchull; Shin, Chang‐Woong; Villanoy, Cesar; Lee, Seok; Min, Hong Sik; Kim, Dong Guk (American Geophysical Union, 2022-02)The northward-flowing Mindanao Undercurrent (MUC) was directly measured by acoustic Doppler current profilers from a subsurface mooring at about 8°N, 127°E during 2 years (November 2017–December 2019). Its depth covers a range from 400 m to deeper than 1,000 m with its core appearing at around 900 m. The mean velocity of MUC's core was approximately 5.8 cm s−1 with a maximum speed of about 47.6 cm s−1. The MUC was observed as a quasi-permanent current with strong intraseasonal variability (ISV) with a period of 70–80 days. Further analyses with an eddy-resolving circulation model output suggest that the ISV is closely related to sub-thermocline eddies (SEs). In this study, two types of SEs near the Philippine coast are disclosed: the westward propagating SE (SE-1) and the quasi-stational SE southeast of Mindanao Island (SE-2). The SE-1 has both cyclonic and anticyclonic polarities with the propagation speed of 7–8 cm s−1, while the SE-2 is an anticyclonic eddy that moves erratically within 4–8°N, 127–130°E with the mean translation speed of about 11 cm s−1. Even though the SE-1 plays an important role in modulating the MUC, our results show that the observed strong MUC event (May–July 2019) is evidently induced by the intensified SE-2 that moves northwestward. This study emphasizes that the SE-2 when intensified, receives more energy from the strengthened New Guinea Coastal Undercurrent and loses the energy northward along the Philippine coast by intensifying the MUC.This study was part of the project entitled “study on air–sea interaction and process of rapidly intensifying Typhoon in the northwestern Pacific” (PM61670) funded by the Ministry of Oceans and Fisheries, Rep. of Korea. This study was also partly supported by the project entitled “Influences of the Northwest Pacific circulation and climate variability on the Korean water changes and material cycle I—The role of Jeju warm current and its variability” (PEA0011) funded by Korea Institute of Ocean Science and Technology (KIOST). The mooring data used in this study were provided by KIOST and are available from the KIOST live access server (http://las.kiost.ac.kr/data_adcp/). The model data are freely available from Mercator Ocean (https://resources.marine.copernicus.eu/?option=com_csw&view=details&product_id=GLOBAL_ANALYSIS_FORECAST_PHY_001_024).
- Vulnerability drivers for small pelagics and milkfish aquaculture value chain determined through online participatory approachMacusi, Edison D.; Geronimo, Rollan C.; Santos, Mudjekeewis D. (Elsevier, 2021-11)Climate change impacts on the fisheries can be short-term or long-term, making them highly vulnerable. Fishers' vulnerability encompasses several factors and includes, among others, their sensitivity, exposure to the elements, and their adaptive capacity. The main aim of this study was to help develop a vulnerability assessment tool that can be applied in the various nodes of the fisheries and aquaculture value chains with a long-term view of enhancing the resilience of the fisheries and helping increase the adaptive capacity of the fishing communities. A participatory technique using online workshops was conducted together with various stakeholders (N = 214) who gave insights and suggested indicators that drive climate change impacts and vulnerability. Based on the online workshops conducted, the common hazards/drivers were increasing temperature, typhoons, flooding (sea-level rise), and the recent pandemic, which consequently destroy coral reef ecosystems, affect fisheries yield, increases fish mortality, damage boats, fishing gears, pens, cages, pond dikes, erode beach properties, and devastate houses. In association with these impacts, mobility, travel, processing, and logistic operations are severely reduced. In the human dimension, the fishers and fish farmers are directly affected in terms of income loss, destroyed fishing gears, nutritional deficiencies and health impacts, less fishing operations, early or reduced harvest yield, and low market value of products. In the adaptation options, the infrastructure, social, economic, awareness/knowledge, and relevant governance/policy dimensions are needed to address and help mitigate various climate change impacts.
- Short-term exposure to independent and combined acidification and warming elicits differential responses from two tropical seagrass-associated invertebrate grazersBaure, Jerwin G.; Roleda, Michael Y.; Juinio-Meñez, Marie Antonette (Springer, 2023-08-10)Ocean acidification and warming could affect animal physiology, key trophic interactions and ecosystem functioning in the long term. This study investigates the effects of four pH−temperature combination treatments simulating ocean acidification (OA), ocean warming (OW) and combined OA and OW conditions (FUTURE) relative to ambient present-day conditions (PRESENT) on the grazing of the juveniles of two seagrass-associated invertebrates namely the sea cucumber Stichopus cf. horrens and topshell Trochus maculatus over a 5-day exposure period. Diel and feeding activity of both species increased under OW and FUTURE to some extent, while the nighttime activity of Trochus but not Stichopus decreased under OA relative to PRESENT during the first 2 days. Fecal production of Stichopus did not differ among treatments, while the lowest fecal production of Trochus was observed under OA during the first 24 h of grazing. These responses suggest that Trochus may be initially more sensitive to OA compared with Stichopus. Interestingly, fecal production of Trochus in FUTURE was significantly higher than OA, suggesting that warming may ameliorate the negative effect of acidification. Diel activity, feeding and fecal production after 5 days did not differ among treatments for both species, suggesting acclimation to the acute changes in temperature and pH after a few days, although Stichopus acclimated rapidly than Trochus. The ability of the two juvenile invertebrate grazers to rapidly acclimate to increased temperature and lowered pH conditions after short-term exposure may favor their survival under projected changes in ocean conditions.This work was supported by the Department of Science and Technology–Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development under Grant QMSR-MRRD-MEC-295-1449. The authors would like to thank Dr. Ian Enochs for his invaluable help in improving this paper. We also thank Tirso Catbagan, Garry Bucol, Rona Soy and Tomilyn Jan Garpa for their assistance during the conduct of this study. We would also like to thank the Marine Biogeochemistry Laboratory of the UP Marine Science Institute for their assistance in analyzing our water samples as well as the DNA Barcoding Laboratory of the UP Institute of Biology for the species identification of our animals.
- Characteristics of marine heatwaves in the PhilippinesEdullantes, Brisneve; Concolis, Brenna Mei M.; Quilestino-Olario, Raven; Atup, Dale Patrick D.; Cortes, Aiza; Yñiguez, Aletta T. (Elsevier, 2023-09)Marine Heatwaves (MHWs) are prolonged, discrete, and anomalously warm events, which have recently gained global attention due to their far-reaching effects and reported impacts. Although intensive studies have been carried out at global and regional scales, these events remained understudied in the Philippines – a country with high marine biodiversity. The Philippines is highly vulnerable to the impacts of these extreme events as it lies in the western boundary of the Pacific that is considered as a hotspot for MHWs. The present study used multi-year climatic sea surface temperature (SST) record to detect MHWs in the Philippines. The detected events were then characterized using the standardized metrics. Linear trend analysis was conducted to determine the magnitude and direction of the change of the MHW metrics over time. Decadal trend revealed that MHWs in the Philippines significantly increased from seven MHWs in the 1980s to 37 MHWs in the last decade. Moreover, increased duration was remarkable in 2020 with 276 MHW days. MHW frequency and duration were increasing at a rate almost twice as its neighboring waters. Intensities did not significantly increase with time, but the highest SST anomaly is associated with El Niño Southern Oscillation. Furthermore, the eastern and western region of the Philippines is vulnerable to MHWs, but hotspots are mostly confined in the West Philippine Sea and western tropical Pacific. An in-depth investigation of the drivers of MHWs is recommended to understand the physical mechanisms of the development of these extreme thermal events in the Philippine seas. The findings have significant implications for coastal marine resource management, highlighting the need for adaptive management strategies and increased monitoring and research efforts to mitigate the impacts of MHWs on marine ecosystems and local economies in the Philippines.
- Fish and benthic communities in an offshore and well-managed coral reef after bleaching disturbance in the PhilippinesQuimpo, Timothy Joseph R.; Requilme, Jeremiah Noelle; Gomez, Elizabeth; Sayco, Sherry Lyn; Dumalagan, Edwin E.; Siringan, Fernando P.; Conaco, Cecilia; Cabaitan, Patrick C. (Springer, 2023-08-29)Climate change is perhaps the greatest threat to coral reefs worldwide. However, there is spatial variation in the extent and severity of this disturbance, with offshore and well-managed reefs presumed to be less vulnerable to anthropogenic disturbance. Here, fish and benthic communities at the offshore and well-managed reefs of Apo Reef Natural Park, Philippines, were examined during a bleaching disturbance in 2016 and reassessed 2 (2018) and 3 years (2019) after using scuba surveys. Results showed that benthic communities varied more strongly with year attributed to changes in the benthic cover of coral. These changes were influenced by site, with some sites experiencing coral loss of 41–48%, while other sites exhibited minimal changes. Site differences in coral loss may be associated with coral cover, with sites that had high coral cover prior to bleaching incurring larger loss of coral cover. Fish communities varied more with sites and was associated with differences in the predominant benthos. The stability of fish communities with year despite coral loss may be attributed to the minimal loss of coral cover at some sites. For sites that experienced high losses of coral cover, the presence of alternative and deeper habitats may have provided shelter and food for more mobile fishes maintaining taxonomic composition within sites. This study shows that bleaching disturbance circumvents effective management, but impacts are variable even at small (≤ 3 km) spatial scales. Benthic community composition and presence of alternative habitats potentially alleviate the negative impacts of bleaching on reef fish diversity and abundance.We are grateful to the laboratory assistants F Castrence, R de Guzman, B Gabuay, R Valenzuela and K Adolfo for their assistance in the fieldwork. We thank the comments and criticisms of two anonymous reviewers that greatly improved the content of this manuscript.
- A multi-framework analysis of stakeholders’ perceptions in developing a localized blue carbon ecosystems strategy in Eastern Samar, PhilippinesQuevedo, Jay Mar D.; Ferrera, Charissa M.; Faylona, Marie Grace Pamela G.; Kohsaka, Ryo (Springer Science and Business Media LLC, 2024-01-25)Blue carbon ecosystems (BCEs) are vital for global climate change mitigation and offer diverse local ecosystem co-benefits. Despite existing literatures on integrating national and international BCE agendas at the local level, the development and implementation of localized BCE strategies often lag behind. To provide insights on this knowledge gap, we present a case study conducted in Eastern Samar, Philippines. Employing a multi-framework analysis- encompassing DPSIR (drivers, pressures, state, impact, responses), SOAR (strengths, opportunities, aspirations, results), and PESTLE (political, economic, social, technological, legal, environmental) frameworks, stakeholder perceptions collected from focus group discussions highlight issues and challenges in developing and implementing a BCE strategy. Findings reveal that the aftermath of Typhoon Haiyan in 2013 in the study sites stimulated conservation efforts and raised awareness, but governance structures and policy enforcement influence the success and longevity of management and conservation efforts. Through the integration of multiple frameworks, this study outlined a potential localized BCE strategy, emphasizing both internal priorities such as stakeholder engagement and alternative livelihoods and external priorities related to policy and technological supports. While developed based on a specific case study in the Philippines, the proposed strategy is presented in a general manner, enabling its potential replication in other provinces in the Philippines or in countries with similar geographic settings.
- Natural and anthropogenic climate variability sgnals in a 237-year-long coral record from the PhilippinesInoue, Mayuri; Fukushima, A.; Chihara, M.; Genda, A.; Ikehara, Minoru; Okai, T.; Kawahata, Hodaka; Siringan, F. P.; Suzuki, Atsushi (American Geophysical Union, 2023-11-29)Both proxy and model studies conducted to understand anthropogenic warming have revealed historical variations in sea-surface temperature (SST) since the industrial revolution. However, because of discrepancies between observations and models in the late nineteenth century, the timing and degree of anthropogenic warming remain unclear. In this study, we reconstructed a 237-year-long record of SST and salinity using a coral core collected from Bicol, southern Luzon, Philippines, which is located at the northern edge of the western Pacific warm pool. The SST record showed volcanic cooling after several volcanic eruptions, including the 1815 Tambora eruption, but the pattern of change differed. Decadal SST variations at Bicol are connected to Pacific Decadal Variability (PDV). Therefore, it is suggested that the PDV conditions at the time of the eruption may have influenced marine conditions, such as the degree and duration of cooling and/or salinity, after the eruptions. Although there were discrepancies in SST variations among the modeled, observed, and proxy SST data from the late nineteenth to early twentieth centuries, SST data from the late twentieth century showed globally coherent anthropogenic warming, especially after 1976. In particular, summer SST in the northwestern Pacific has become more sensitive to anthropogenic forcing since 1976.