Effect of Nutrient Over-enrichment on Spatiotemporal Variability of Phytoplankton in Manila Bay, Philippines

To understand Manila Bay’s current condition, physicochemical parameters were correlated with net phytoplankton composition from 2012 to 2015. Nitrate concentrations reached 24.18 µM, which is above the critical value (5 µM) recommended by the Philippine Department of Environment and Natural Resources and ASEAN. Hypoxia has been observed with dissolved oxygen levels as low as 1.47 mg L-1. Phytoplankton composition varies but dominated by Chaetoceros curvisetus, Skeletonema costatum, Thalassiosira sp., and Thalassionema nitzchiodes. Phytoplankton densities also vary between seasons but mostly concentrated in stations near the tributaries and urban areas. Trends in both phytoplankton and physicochemical properties suggest that the ecosystem of the bay is highly dependent on rainfall. Shannon-Wiener diversity index does not go higher than 2.46 and based on monthly averages, the bay can be categorized as moderately heavy to heavy polluted. A watershed system approach is urgently needed since found heavy eutrophication generally occurs in estuaries near urban and industrial areas.

Bibliographic Details

Main Authors:	Vergara, James Dominic D., Jose, Ellaine C., Borja, Valeriano M., Gatdula, Norvida C., Metillo, Ephrime B., Santos, Mudjekeewis D., Furio, Elsa F.
Other Authors:	Aquatic Ecology Section, Capture Fisheries Research and Development Division, National Fisheries Research and Development Institute
Format:	article biblioteca
Language:	English
Published:	2017
Subjects:	Ecology, Environment, Fisheries, eutrophication, Manila Bay, hypoxia, watershed, nutrients,
Online Access:	http://hdl.handle.net/1834/41164
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