Abstract
Composition and Abundance of Plankton Communities in Mangrove Estuary of Tubajon, Philippines
Charity May L. Dacayana1 , Tom Gerald T. Genovia2 , Renelyn M. Balagot2
Tubajon has a semi-enclosed estuary characterized by shallow depth and slow
water exchange being disrupted by a mangrove barrier. In an attempt to assess
the environmental condition of the mangrove estuary of Tubajon, this study
aimed to determine the composition and abundance of plankton as a
bioindicator in the aquatic environment along with the physicochemical
parameters. The data of water depth obtained with a sinker were processed
using the Surfer software to generate the bathymetric profile of the area.
The sensor data logger was used to determine the temperature, salinity, pH, and
dissolved oxygen of water. The spectrophotometric method determined the
chlorophyll-a content of water, and the cadmium copper method measured
the nitrate concentration. Plankton was identified up to the generic level using the
taxonomic keys. Results showed a total of 18 taxa of phytoplankton belonging
to dinoflagellates and diatoms that were able to adapt the lower light
conditions and nutrient-impoverished water. Dinoflagellates were the most
numbered phytoplankton. Among the nine taxa of zooplankton enumerated,
copepods were the dominant group. Chlorophyll-a content (<0.05 µg/L),
dissolved oxygen (<4 mg/L) and nitrate concentration (<0.1 ppm) were relatively
small indicating less productivity and oligotrophic condition. The composition
and abundance of plankton in the area along with the physicochemical condition
might be due to less water exchange, high water retention resulting from the
presence of a mangrove barrier, and the anthropogenic activities by the adjacent
settlers. This study may provide relevant information for any conservation effort
in the area.
KEYWORDS: bathymetric, bioindicator, chlorophyll-a, oligotrophic, zooplankton
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