title: Phosphorus as a driver of nitrogen limitation and sustained eutrophic conditions in Bolinao and Anda, Philippines, a mariculture-impacted tropical coastal area.
abstract: 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 4μM 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.
authors.affiliation: Department of Mechanical and Environmental Informatics, Graduate School of Information Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1 W8-13 Meguro, Tokyo 152-8552, Japan. Electronic address: cmferrera@gmail.com.
authors.forename: Charissa M
authors.initials: CM
authors.lastname: Ferrera
authors.affiliation: Department of Mechanical and Environmental Informatics, Graduate School of Information Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1 W8-13 Meguro, Tokyo 152-8552, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Watanabe
authors.affiliation: Marine Biogeochemistry Group, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8564, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Miyajima
authors.affiliation: Marine Science Institute, University of the Philippines, Diliman, Quezon City 1101, Philippines.
authors.forename: Maria Lourdes
authors.initials: ML
authors.lastname: San Diego-McGlone
authors.affiliation: Marine Biogeochemistry Group, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8564, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Morimoto
authors.affiliation: Faculty of Fisheries, Nagasaki University, 1-14 Bunkyo, Nagasaki 852-8521, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Umezawa
authors.affiliation: Institute of Civil Engineering, University of the Philippines, Diliman, Quezon City 1101, Philippines.
authors.forename: Eugene
authors.initials: E
authors.lastname: Herrera
authors.affiliation: Japan International Cooperation Agency, Tokyo 102-8012, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Tsuchiya
authors.affiliation: Department of Mechanical and Environmental Informatics, Graduate School of Information Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1 W8-13 Meguro, Tokyo 152-8552, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Yoshikai
authors.affiliation: Department of Mechanical and Environmental Informatics, Graduate School of Information Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1 W8-13 Meguro, Tokyo 152-8552, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nadaoka
mesh_terms: D000818:Animals; D004784:Environmental Monitoring; D005068:Eutrophication; D005399:Fishes; D005618:Fresh Water; D009584:Nitrogen / Q000032:analysis*; D010679:Philippines; D010758:Phosphorus / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus; D009584:Nitrogen
keywords: Bolinao; Eutrophication; Fish feed; Mariculture; Nutrient ratios; Phosphorus