1. Elemental and Isotopic Techniques to Trace the Nutrient Sources in the Neritic Zone and Provenance of White Beach Sand of Boracay Island, the Philippines.
- Author
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Racadio, Charles Darwin T., Sucgang, Raymond J., Mendoza, Norman D. S., and Racho, Joseph Michael D.
- Subjects
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CHEMICAL oxygen demand , *NATURAL resources , *ALGAL blooms , *SEAWATER , *VOLCANIC ash, tuff, etc. - Abstract
Adjudged as one of the world's most beautiful beaches, Boracay Island has seen an increase in tourist arrivals and an unprecedented increase in hotel and business establishments over the past few decades. Water quality tests of the beach water in the neritic zone suggest coliform contamination, which is especially high in Bulabog Beach. Chemical oxygen demand and nitrate concentration are still below the limits set for Class SB marine waters by the Department of Environment and Natural Resources. Elemental compositions of corals, sediments, algae, terrestrial soil, and volcanic ash reveal that corals are the most probable source of the island's white beach sand, contrary to local beliefs that the algal blooms are the eternal source of the island's white sand. Isotopic data also substantiate this. δ15N and δ13C data show that algae most probably get its nutrients from septic, canal, and sewage discharges, whereas a few corals assimilate inorganic fertilizer nutrients possibly from run-offs, which carry the inorganic fertilizers from golf courses. Based on binary mixing models, canal and sewer waters contribute about 80-94% of the water collected from Sites 3, 6, and 7, which causes a shift in the δ18O isotopic signatures of seawater in these areas. [ABSTRACT FROM AUTHOR]
- Published
- 2024