00. Ocean Decade - Philippines
Permanent URI for this communityhttps://repository.unesco.gov.ph/handle/123456789/7
The UNACOM Online and Digital Enabling Library and Index is developed to support the alignment of research, investments, and community initiatives toward contributing to a well-functioning, productive, resilient, sustainable, and inspiring ocean. The goal is to enable the government, partner agencies, and UNESCO to develop more robust Science-Informed Policies and facilitate a stronger Science-Policy Interface through the gathered data, information, and knowledge related to the Ocean Decade in the Philippines.
Particularly, it aims to:
Particularly, it aims to:
- Gather and index all publications, reports, policies, laws, legislations, articles, and other documents of the Philippine National Committee on Marine Sciences (NCMS) related to the Ocean Decade.
- Disseminate and promote these publications, reports, policies, and other documents on the initiatives and actions to address the Ocean Decade challenges.
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- Juvenile scleractinian assemblage and its association with adults and benthos at shallow and upper mesophotic depths in fringing and atoll reefs in the PhilippinesAlbelda, Ritzelle L.; Cabaitan, Patrick C.; Sinniger, Frederic P.; Dumalagan, Edwin Jr; Quimpo, Timothy Joseph R.; Olavides, Ronald Dionnie D.; Munar, Jeffrey C.; Villanoy, Cesar L.; Siringan, Fernando (Elsevier B.V, 2020-10-15)The juvenile stage is a critical part of a scleractinian’s life history as it is when they are highly vulnerable to various post-settlement mortality processes, which influence the structure of adult scleractinian assemblages. Although numerous studies have been done to understand dynamics of juvenile assemblages at shallow water reefs (SWRs), similar studies on deeper and less explored reefs, such as mesophotic coral ecosystems (MCEs) remain limited. Using diver-based photo-quadrat method, we aimed to examine how juvenile scleractinian assemblages vary from SWRs (shallow: 3 to 10 m and middle: 10 to 20 m) to upper MCEs (deep: 30 to 40 m) in the fringing and atoll reefs in the Apo Reef Natural Park, Philippines. We also aimed to understand the potential association of juvenile scleractinian densities with adult scleractinian densities and benthic cover. A total of 12 families were recorded for both juveniles and adults with Poritidae being the most abundant, followed by Pocilloporidae and Acroporidae (and Merulinidae for juveniles only). Juvenile densities (ranging from 14 to 36 individuals/m2) varied among depth zone and reef type interactions and had a bimodal distribution, with the middle zone having the lowest density compared to the shallow and deep zones. Juvenile densities were correlated to benthic cover, particularly to high algal cover in the middle zone and availability of bare hard substrate in the shallow zone. Adult densities were also correlated with juvenile densities, but not commonly in the middle zone, emphasizing that it is only one of the many variables that contribute to juvenile assemblages. This study is the first to document juvenile scleractinian assemblages, how they vary from SWRs to MCEs in the Philippines and the Coral Triangle, and demonstrates the importance of benthos and adult brood stock in shaping juvenile scleractinian assemblages across depth zones.
- Clay mineral nanostructures regulate sequestration of organic carbon in typical fluvial sedimentsSong, Hongzhe; Liu, Zhifei; Lin, Baozhi; Zhao, Yulong; Siringan, Fernando P.; You, Chen-Feng (Elsevier, 2024-02-15)The association between clay minerals and organic carbon is pivotal for understanding transport, burial, and preservation processes of sedimentary organic carbon. However, fine-scale microscopic studies are still limited in assessing the effect of diverse clay mineral structures and properties on organic carbon sequestration. In this study, we employed X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy coupled with energy dispersive spectroscopy and electron energy loss spectroscopy analyses to investigate the nanoscale interaction between clay minerals and organic carbon of two typical fluvial sediment samples with contrasting clay mineral compositions and organic carbon origins. Sample from Taiwan shows abundant illite and chlorite with petrogenic organic carbon, while sample from Luzon has significant smectite with pedogenic organic carbon. We observed that the nanostructure of the clay minerals controls the distribution of organic carbon. In the Luzon sample, the organic carbon is tightly associated with smectite, occupying expandable interlayer spaces. In the Taiwan sample, however, the organic carbon is primarily confined on the surface and edge of illite. These findings offer valuable insights into the selective association of organic carbon with clay minerals and underscore the role of clay mineral nanolayer structures in governing the occurrence and preservation of organic carbon in sediments. A comprehensive understanding of these interactions is crucial for accurate assessments of carbon cycling and sequestration in the natural environment.We sincerely thank Shunai Che and Lu Han for their help in TEM experiments and data processing. We thank Editor Dr. Andrew Hursthouse for handling the manuscript and two anonymous reviewers for their constructive comments on the early version of this paper. This work was supported by the National Natural Science Foundation of China (42130407, 42188102, 42306066) and the Interdisciplinary Project of Tongji University (ZD-22-202102).
- Estimation of the vertical phytoplankton distribution in the Philippine Sea: Influence of turbulence following passage of typhoonsCordero-Bailey, Kristina S.A.; Almo, Aldwin T.; David, Laura T.; Yñiguez, Aletta T. (Elsevier, 2022-11)The subsurface chlorophyll-a maximum (SCM) is a phenomenon that contributes significantly to the total primary production of the open ocean but it is not observable from remote sensing, thus primary production based on satellite information is highly underestimated. In a highly dynamic region such as the Philippine Sea, turbulence caused by tropical storms may exert significant impact on the SCM feature. In this study, we attempt to estimate the vertical phytoplankton profile in the Philippine Sea from remote sensing images by applying a generic quantitative approach. Generalized Additive Models (GAM) followed by Generalized Linear Models (GLMs) were used create predictive equations between response variables (Chl-a profile parameters) and predictor variables (RS parameters). GAM was able to predict integrated Chl-a biomass using photosynthetic active radiation (PAR), wind speed and wind stress, the depth of the Chl-a peak using surface Chl-a, wind speed and wind stress, and the baseline Chl-a concentration using sea surface temperature, sea surface salinity and PAR. GLM found wind stress and wind speed as significant predictors for integrated Chl-a biomass, while surface Chl-a, wind speed and wind stress were significant predictors for depth of the Chl-a peak. When the predictive equations were applied to 2020 monthly satellite images, they were seen to adequately estimate the offshore spatial distribution of the two Chl-a parameters. Increased turbulence due to high wind speed and wind stress during passage of tropical storms was seen to result in shallowing of the SCM and subsequent increase in Chl-a within the water column. These equations could be refined if long-term observational data was available. The capacity to estimate vertical distribution of primary productivity in the Philippines provides a means to better understand fisheries productivity and biogeochemical cycling in the region.
- Submerged reef features in Apo and Tubbataha Reefs, Philippines, revealed paleo sea-level history during the last deglaciationMunar, Jeffrey C.; Aurelio, Mario A.; Dumalagan, Edwin E.; Tinacba, Erin Joy C.; Doctor, Ma. Angelique A.; Siringan, Fernando P. (Springer, 2024-02-27)The morphology of coral reefs provides an effective benchmark of past sea levels because of their limited vertical range of formation and good geologic preservation. In this study, we analyze the seafloor morphology around two atolls in the Philippines: Tubbataha Reef, in Palawan, and Apo Reef, in Occidental Mindoro. High-resolution multibeam bathymetry to a depth of 200 m reveals seafloor features including reef ridges and staircase-like terraces and scarps. Depth profiles across the reefs show terraces formed within six and seven depth ranges in Tubbataha Reef and in Apo Reef, respectively. These were further observed through a remotely operated vehicle. The terraces and scarps are interpreted as backstepping reefs that were drowned during an overall rise in sea level from the Last Glacial Maximum (LGM). Terraces are used as indicators of paleo sea level and the separation between terraces as the magnitude of sea-level rises coeval with meltwater pulse events during the last deglaciation. The pattern for both Apo and Tubbataha reefs indicates subsidence, consistent with the absence of Holocene emergent features and their atoll morphologies. Subsidence of up to 17 m since the LGM in Apo Reef is mainly attributed to the downbowing of the crust toward Manila Trench. In Tubbataha Reef, subsidence of up to 14 m is attributed to the continuous cooling of the volcanic crust underlying the atoll. These can be used to fill gaps in the tectonic history of the study sites from the last deglaciation.This study was funded by the Department of Science and Technology–Philippine Council for Agriculture, Aquatic and Natural Resources Research Development (DOST-PCARRD) Geophysical Coral Mapping Project and Acquisition of Detailed Bathymetry for Coastal Erosion Management Project both under F. P. Siringan, and National Assessment of Coral Reef Environment (NACRE) Project under Hazel Arceo. We would like to mention, in particular, Dominic Jone Cabactulan, Timothy Quimpo, Ronald Olavides, Mary Ann Calleja, Patrick Cabaitan, and Cesar Villanoy who were members of the project team. We thank the Tubbataha Management Office, Sablayan Local Government Unit, and Department of Environment and Natural Resources for the work permits and logistical help during the surveys.
- 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.
- 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.
- Genus and size-specific susceptibility of soft corals to 2020 bleaching event in the PhilippinesBaran, Christine; Luciano, Rhea Mae A.; Segumalian, Christine; Valino, Darryl Anthony; Baria-Rodriguez, Maria Vanessa (Taylor & Francis, 2023-05-08)Soft corals are zooxanthellate sessile animals supporting various organisms in coral reefs. However, their populations are threatened by the impacts of ocean warming. Under thermal stress conditions, soft corals may experience mild to severe bleaching which may lead to death. Understanding soft coral bleaching responses highlights the importance in predicting how populations and diversity may be affected by changing climate scenarios. In this study, we examined the bleaching responses of the three dominant soft coral genera (Lobophytum, n = 1318; Sarcophyton, n = 116; Sinularia, n = 639 colonies) in the Bolinao-Anda Reef Complex (BARC), Pangasinan, north-western Philippines during the 2020 thermal stress event in terms of genus and colony size susceptibility, and zooxanthellae density. Degree heating week (DHW) data from 1986–2020 were obtained using remotely sensed data to determine thermal anomalies in the study sites. The maximum DHW (6.3) in 2020 occurred between July–August while bleaching surveys were done during October of the same year. The percentage of bleached portions in each colony was used to determine bleaching category: no bleaching (0%), moderately bleached (1–50%) and heavily bleached (>50%). Quantification of bleaching prevalence and susceptibility of colony sizes were determined by colony count and mean diameter measurements taken from quadrat photographs in October 2020. Haphazard tissue collection (∼3 cm) in each colony of three soft coral genera per bleaching category was done to quantify zooxanthellae density. Results showed that Lobophytum colonies had the lowest bleaching prevalence (41%), followed by Sinularia (66%) and Sarcophyton (78%). All colony size classes of the three genera were susceptible to bleaching. However, smaller colonies of Lobophytum (<15 cm), Sarcophyton (<5 cm) and Sinularia (<5 cm) showed less susceptibility than large colonies. Zooxanthellae density was significantly reduced in moderately and heavily bleached colonies. The results of this study highlight that bleaching susceptibility is genus specific, with Sarcophyton and Sinularia being more susceptible to bleaching than Lobophytum. Smaller colonies seemed to be less susceptible to bleaching than large-sized soft corals suggesting a differential thermal stress response. Spatial variations in bleaching prevalence were also found among reef sites with varying environmental conditions and thermal stress histories. This work provided initial observations on how bleaching affects soft corals. Further studies on soft coral community recovery are recommended to fully understand how these organisms perform after thermal stress events.We acknowledge the Bolinao Marine Laboratory of the University of the Philippines for logistics and fieldwork assistance. Thanks to Kevin Yatco and Socorro Rodrigo for providing technical assistance in obtaining remotely sensed temperature data. Thank to Kevin Yatco and Socorro Rodrigo, and Kevin Labrador for providing technical assistance in obtaining remotely sensed temperature data and assistance in statistical analysis, respectively.