menu.header.image.unacom.logo
 

National Committee on Marine Sciences (NCMS)

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

Browse

Filters

2021 - 20232

Settings

AGROVOC Keyword: search.filters.agrovoc.coral bleachingAuthor: search.filters.author.Baria-Rodriguez, Maria Vanessa

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    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.
  • No Thumbnail Available
    Genus and size-specific susceptibility of soft corals to 2020 bleaching event in the Philippines
    Baran, 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.