Spatial dietary shift in bivalves from embayment with river discharge and mariculture activities to outer seagrass beds in northwestern Philippines
- 429 Downloads
To investigate the spatial variation in bivalve food sources along a pollution gradient and assess bivalve contribution to biogeochemical cycles in tropical coastal ecosystems, the δ13C and δ15N values of bivalves and their potential food sources were studied in northwestern Philippines. In a semi-enclosed embayment affected by river discharge and mariculture activities, bivalves depended primarily on 13C-depleted suspended particulate organic matter such as phytoplankton and/or fish feeds. However, toward the relatively oligotrophic seagrass beds, the bivalve food source gradually shifted to more 13C-enriched resuspended and/or settled particles. Furthermore, in the outer seagrass beds exposed to the open ocean, bivalves mainly relied on similar food sources, such as detritus of microalgae, regardless of the distance from the embayment. These trends appear to reflect the ready availability of the food sources. Especially in the outer seagrass beds, a semi-closed material cycle within the vicinity of the sea bottom likely emerged between bivalves and algae, but not between the phytoplankton in the overlying water column. This resulted in a relatively weak benthic-pelagic coupling for bivalves. These cycles would need to be taken into account when estimating the biogeochemical cycles in eutrophicated coastal areas.
KeywordsPhytoplankton Bivalve Particulate Organic Matter Particulate Organic Carbon Sedimentary Organic Matter
We thank K. Nadaoka and M.D. Fortes for leading this project. We are also grateful to C.M. Ferrera, T. Tsuchiya, E.C. Herrera, J.C. Rengel, M. Atrigenio, D.L. Mancenido, T. Yamamoto, L. Bernardo, A.S.J. Wyatt and staff of University of the Philippines (UP), and UP Marine Science Institute Bolinao Marine Laboratory (BML) for supporting field work. We are also sincerely thankful to the JICA Philippines office and to Y. Nagahama, Y. Geroleo, and the CECAM coordinating office for all logistic arrangements.
Compliance with ethical standards
The present study was supported by the Japan International Cooperation Agency (JICA) and Japan Science and Technology Agency (JST) through the Science and Technology Research Partnership for Sustainable Development Program (SATREPS) under the project “Integrated Coastal Ecosystem Conservation and Adaptive Management under Local and Global Environmental Impacts in the Philippines (CECAM)”, and by JSPS Grant-in-aid for Overseas Scientific Research Grant Number 23405002 (Granted to T.M.).
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.
- Bayne BL, Hawkins AJS (1992) Ecological and physiological aspects of herbivory in benthic suspension-feeding molluscs. In: John DM, Hawkins SJ, Price JH (eds) Plant–animal interactions in the marine benthos. Clarendon Press, Oxford, pp 265–288Google Scholar
- Bayne BL, Newell RC (1983) Physiological energetics of marine molluscs. In: Saleudin ASM, Wilburg KM (eds) The Mollusca, vol 4. Academic Press, New York, pp 407–515Google Scholar
- David LT, Pastor-Rengel D, Talaue-McManus L, Magdaong E, Salalila-Aruelo R, Bangi HG, San Diego-McGlone ML, Villanoy C, Cordero-Bailey K (2014) The saga of community learning: Mariculture and the Bolinao experience. Aquat Ecosyst Health Manag 17(2):196–204Google Scholar
- Ferrera CM, Watanabe A, Miyajima T, San Diego-McGlone ML, Morimoto N, Umezawa Y, Herrera E, Tsuchiya T, Yoshikai M, Nadaoka K (2016) Phosphorus as a driver of nitrogen limitation and sustained eutrophic conditions in Bolinao and Anda, Philippines, a mariculture-impacted tropical coastal area. Mar Pollut Bull 105:237–248CrossRefGoogle Scholar
- Fortes MD, Go GA, Bolisay K, Nakaoka M, Uy WH, Lopez MR, Leopardas V, Leriorato J, Pantallano A, Paciencia FJ, Watai M, Honda K, Edralin M (2012) Seagrass response to mariculture-induced physico-chemical gradients in Bolinao, northwestern Philippines. Proc 12th Int Coral Reef Symp 9–13Google Scholar
- Gabbott PA (1975) Storage cycles in marine bivalve molluscs: a hypothesis concerning the relationship between glycogen metabolism and gametogenesis. In: Barnes H (ed) Proc 9th Europ Mar Biol Symp. Aberdeen Univ Press, Aberdeen, pp 191–211Google Scholar
- Harlin MM (1973) Transfer of products between epiphytic marine algae and host plants. J Phycol 9:243–248Google Scholar
- Larkum A, Orth RJ, Duarte CM (2006) Seagrasses: biology, ecology and conservation. Springer, The NetherlandsGoogle Scholar
- Newell RIE (2004) Ecosystem influences of natural and cultivated populations of suspension-feeding bivalve molluscs: a review. J Shellfish Res 23(1):51–61Google Scholar
- Parsons TR, Takahashi M, Hargrave B (1984) Biological oceanographic processes, 3rd edn. Pergamon Press, UKGoogle Scholar
- Tamondong AM, Blanco AC, Fortes MD, Nadaoka K (2013) Mapping of seagrass and other benthic habitats in Bolinao, Pangasinan using Worldview-2 satellite image. Proc IEEE IGARSS, 1579–1582Google Scholar
- Wada E (1980) Nitrogen isotope fractionation and its significance in biogeoehemical processes occurring in marine environments. In: Goldberg ED, Horibe Y, Saruhashi K (eds) Isotope Marine Chemistry. Uchida Rokkakuho, Tokyo, pp 375–398Google Scholar
- White PG (2009) EIA and monitoring for clusters of small-scale cage farms in Bolinao Bay: a case study. In FAO Environmental impact assessment and monitoring of aquaculture. FAO Fisheries and Aquaculture Technical Paper, No. 527. FAO, Rome, pp 537–552Google Scholar
- WoRMS Editorial Board (2016) World Register of Marine Species. Available from http://www.marinespecies.org at VLIZ. Accessed 21 Jan 2016
- Yoshikai M (2016) Analysis of environmental impacts of intensive mariculture activities on hypoxic water formation and seagrass bed degradation in Bolinao and Anda, Philippines. Master thesis, Tokyo Institute of TechnologyGoogle Scholar