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Journal Articles - UP - MSI

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AGROVOC Keyword: search.filters.agrovoc.coral bleachingAuthor: search.filters.author.Valino, Darryl Anthony M.

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    Zooxanthellae diversity and coral-symbiont associations in the Philippine archipelago: specificity and adaptability across thermal gradients
    Torres, Andrew F.; Valino, Darryl Anthony M.; Ravago-Gotanco, Rachel (Frontiers Media SA, 2021-10-20)
    Prolonged thermal stress and high levels of solar irradiance can disrupt the coral-algal symbiosis and cause bleaching and lowered overall fitness that lead to the likely death of the cnidarian host. Adaptive bleaching and acclimatization of corals, which posits bleaching as an opportunity for the coral host to switch its currently susceptible endosymbionts to more stress-tolerant taxa, offers hope for survival of reefs amid rapidly warming oceans. In this study, we explored the diversity and distribution of coral-zooxanthellae associations in the context of geospatial patterns of sea surface temperature (SST) and thermal anomalies across the Philippine archipelago. Thermal clusters based on annual sea surface temperature means and each site’s frequency of exposure to heat stress were described using three-decade (1985–2018) remotely sensed data. Haphazard sampling of 628 coral fragments was conducted in 14 reef sites over 3 years (2015–2018). Using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting and sequencing of the zooxanthellae ITS2 region, we characterized endosymbiont diversity within four reef-building coral families across archipelagic thermal regimes. Consistency in dominant Symbiodiniaceae taxon was observed in Acropora spp., Porites spp., and Heliopora coerulea. In contrast, the family Pocilloporidae (Pocillopora spp., Seriatopora spp., and Stylophora pistillata) exhibited biogeographic variability in zooxanthellae composition, concordant with inferred occurrences of sustained thermal stress. Multivariate analyses identify two broad Pocilloporidae clusters that correspond with mean SST ranges and frequency of exposure to bleaching-level thermal stress which are largely supported by ANOSIM. Differences in zooxanthellae assemblages may reflect host-specific responses to ecological or environmental gradients across biogeographic regions. Such patterns of variability provide insight and support for the adaptability and potential resilience of coral communities in geographically and oceanographically complex regions, especially amidst the increasing severity of global and local-scale stressors.
    This paper is dedicated to the late Ronald D. Villanueva whose contribution to the project during its inception has been invaluable. The authors thank Patrick R. Pata and the reviewers LE and RC-T for their helpful comments and suggestions, and acknowledge Hazel O. Arceo, Cesar L. Villanoy, and Maria Lourdes San Diego-McGlone for their support of this study. Eileen Peñaflor and Mariana Soppa shared key knowledge in processing satellite products. Mikhael Tañedo, Romer Albino, Emmeline Jamodiong, David Siquioco, Lovely Heyres, Rhea Luciano, Joey Cabasan, Frederico Sabban, Geminne Manzano, Clairecynth Yu, Joyce Velos, Joseph Garcia, Robert Casauay, Maryjune Cabiguin, Macy A onuevo-Arcega, Ariel Loja, Jerome Genilan, Amabelle Go, Jamie Dichaves, Elaine Saniel, and Miledel Quibilan assisted with field collections. Supporting hard coral data were provided by the DOST-PCAARRD NACRE Program and the DENR-BMB WPS and SECURE Philippine Rise Projects. This is MSI contribution number 486.
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    Responses of Buluan Island turbid fringing reefs, southern Philippines to the 2016 thermal anomaly
    Valino, Darryl Anthony M.; Baria-Rodriguez, Maria Vanessa; Dizon, Romeo M.; Aliño, Porfirio M. (Elsevier B.V., 2021-03)
    Coral beaching due to increasing sea surface temperature causes a decline of global reef ecosystems. Turbidity and sedimentation are localized threats that may contribute to and exacerbate the impacts of coral bleaching. Some reports show coral communities thriving in turbid conditions are resilient to bleaching-related mortality events. In the Philippines, information on the effects of turbidity and elevated levels of light attenuation on bleaching in coral assemblages is generally lacking. This study describes the response to coral bleaching of a turbid reef in Buluan Island Marine Sanctuary (BIMS), southern Philippines. Coral cover and diversity showed no changes after the bleaching event. Coral community composition and abundance in some genera were affected but the majority showed either no significant change or recovery to pre-bleaching state even with high bleaching index values. The dominance and presence of bleaching-susceptible genera even after the 2016 global bleaching event suggest that turbidity experienced in BIMS might have reduced the impact of intense irradiance on the reef. Findings from this study indicate the potential existence of turbid resilient reefs across the Philippines and recommend that they be immediately identified and protected.