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National Committee on Marine Sciences (NCMS)

Permanent URI for this communityhttps://repository.unesco.gov.ph/handle/123456789/6

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Author: search.filters.author.Siringan, FernandoOcean Decade Challenge: search.filters.odc.Challenge 2: Protect and restore ecosystems and biodiversity

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    Quantifying vertical land motion at tide gauge sites using permanent scatterer interferometric synthetic aperture radar and global navigation satellite system solutions
    Reyes, Rosalie; Bauzon, Ma. Divina Angela; Pasaje, Nikki Alen; Alfante, Rey Mark; De Lara, Pocholo Miguel; Ordillano, Marion; Flores, Paul Caesar; Rediang, Abegail; Nota, Patrick Anthony; Siringan, Fernando; Blanco, Ariel; Bringas, Dennis (Springer, 2022-01-29)
    One of the consequences of climate change is sea level rise (SLR). Near the coast SLR varies at different locations due to the contributions from regional/local climatic and non-climatic factors. Vertical land motion (VLM) can affect the accuracy of sea level observations from tide gauges (TG) that may exacerbate coastal area inundation/flooding. This study investigated the viability of Permanent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) to quantify the rate of VLM at the TG sites. Measurements from TG co-located GNSS receivers provide the actual VLM rates and ground truth for PSInSAR-derived rates. Based on the results from the 9 study sites, almost all except one are subsiding. Both PSInSAR and GNSS solutions showed the same trend with rates that correlate at 0.89. Analysis from 20 Active GNSS stations showed 95% of the sites are undergoing land subsidence. This should be a cause of concern for communities near the coastal areas.
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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 Philippines
    Albelda, 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.