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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:
  • 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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2014 - 201922020 - 20231

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Author: search.filters.author.Miyajima, ToshihiroSDG: search.filters.sdg.SDG 14 - Life below water

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Now showing 1 - 3 of 3
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    Sedimentary blue carbon dynamics based on chronosequential observations in a tropical restored mangrove forest
    Ray, Raghab; Suwa, Rempei; Miyajima, Toshihiro; Munar, Jeffrey; Yoshikai, Masaya; San Diego-McGlone, Maria Lourdes; Nadaoka, Kazuo (Copernicus GmbH, 2023-03-03)
    Among the many ecosystem services provided by mangroves, the sequestration of large amounts of organic carbon (OC) in marine ecosystems (also known as “blue carbon”) has given these unique ecological environments enormous global attention. While there are many studies on the blue carbon potential of intact mangroves (i.e., naturally growing), there have been very few studies on restored mangroves (i.e., planted). This study aims to address this knowledge gap by examining the sediment development process during the early colonization (rehabilitation) of mangroves in an OC-poor estuary in Panay Island, Philippines. Based on source apportionment of multiple end-members in the sedimentary organic matter, the contribution of mangrove plant material was higher at the older sites compared to the younger sites or bare sediments where there is a higher contribution of riverine input. A clear increasing gradient according to mangrove development was observed for bulk OC (0.06–3.4 µ mol g−1, porewater OC (292–2150 µmol L−1, sedimentary OC stocks (3.13–77.4 Mg C ha−1), and OC loading per surface area (7–223 µmol m−2). The estimated carbon accumulation rates (6–33 mol m−2 yr−1) based on chronosequence are within the global ranges and show an increasing pattern with the age of mangroves. Hence, the sediments of relatively young mangrove forests appear to be a significant potential C sink, and short-term chronosequence-based observations can efficiently define the importance of mangrove restoration programs as a potential carbon sequestration pathway.
    We are grateful to the Japan International Cooperation Agency (JICA) and the Japan Science and Technology Agency (JST) through the Science and Technology Research Partnership for Sustainable Development (SATREPS) program for financially supporting the project Comprehensive Assessment and Conservation of Blue Carbon Ecosystems and their Services in the Coral Triangle (Blue CARES). We thank Jesus Abad, John Michael Aguilar, Dominic Bautista, Bryan C. Hernandez, and Tsuyoshi Kanda for their assistance during field surveys. We are grateful for the overall support given to the project by the University of the Philippines, Diliman, and Aklan State University. We are thankful to our Blue CARES colleague Charissa Ferrera for the support in language edits. Finally, authors sincerely thank AE (Jack Middelburg) and the reviewers for their constructive comments that have greatly improved the revised version of the manuscript.
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    Phosphorus as a driver of nitrogen limitation and sustained eutrophic conditions in Bolinao and Anda, Philippines, a mariculture-impacted tropical coastal area
    Ferrera, Charissa M.; Watanabe, Atsushi; Miyajima, Toshihiro; San Diego-McGlone, Maria Lourdes; Morimoto, Naoko; Umezawa, Yu; Herrera, Eugene; Tsuchiya, Takumi; Yoshikai, Masaya; Nadaoka, Kazuo (Elsevier, 2016)
    The dynamics of nitrogen (N) and phosphorus (P) was studied in mariculture areas around Bolinao and Anda, Philippines to examine its possible link to recurring algal blooms, hypoxia and fish kills. They occur despite regulation on number of fish farm structures in Bolinao to improve water quality after 2002, following a massive fish kill in the area. Based on spatiotemporal surveys, coastal waters remained eutrophic a decade after imposing regulation, primarily due to decomposition of uneaten and undigested feeds, and fish excretions. Relative to Redfield ratio (16), these materials are enriched in P, resulting in low N/P ratios (~ 6.6) of regenerated nutrients. Dissolved inorganic P (DIP) in the water reached 4 μM during the dry season, likely exacerbated by increase in fish farm structures in Anda. DIP enrichment created an N-limited condition that is highly susceptible to sporadic algal blooms whenever N is supplied from freshwater during the wet season.
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    17-year change in species composition of mixed seagrass beds around Santiago Island, Bolinao, the northwestern Philippines
    Tanaka, Yoshiyuki; Go, Gay Amabelle; Watanabe, Atsushi; Miyajima, Toshihiro; Nakaoka, Masahiro; Uy, Wilfredo H.; Nadaoka, Kazuo; Watanabe, Shuichi; Fortes, Miguel D. (Elsevier, 2014)
    Effects of fish culture can alter the adjacent ecosystems. This study compared seagrass species compositions in 2012 with those in 1995, when fish culture was less intensive compared to 2012 in the region. Observations were conducted at the same four sites around Santiago Island, Bolinao: (1) Silaqui Island, (2) Binaballian Loob, (3) Pislatan and (4) Santa Barbara, and by using the same methods as those of Bach et al. (1998). These sites were originally selected along a siltation gradient, ranging from Site 1, the most pristine, to Site 4, a heavily silted site. By 2012, fish culture had expanded around Sites 2, 3 and 4, where chlorophyll a (Chl a) was greater in 2012 than in 1995 by one order of magnitude. Enhalus acoroides and Cymodocea serrulata, which were recorded in 1995, were no longer present at Site 4, where both siltation and nutrient load are heavy.