Concurrent assessment of water parameters and vital-based zooplankton community in an industrial harbor

Abstract

Zooplankton are the most abundant organisms in marine as well as are sensitive to environmental stresses. This study compared the communities of zooplankton as an indicator of water quality together with and without considering the survivorship of vital condition. Samples of seawater and zooplankton were collected in the inside and outside Kaohsiung Harbor, Taiwan, to understand their relationship. The relatively lower salinity, pH, and dissolved oxygen, as well as the higher nutrients, suspended solids, and metals concentrations, were found in the seawater that collected from the estuary region located on the inside harbor, accompanied with the lower abundance and survival rate of zooplankton. Results suggested that the survivorship of total zooplankton varied between 17.3 and 79.6%, the high values of 67.4 ± 8.6% were observed outside harbor whereas the low values of 41.9 ± 13.2% were found at inside harbor. Using the density of live zooplankton to carry out cluster analysis showed a more clear division of sites among estuaries, harbor channel, and harbor outside than using that of the total zooplankton. The traditional zooplankton monitoring may misestimate the abundance and composition because it identifies all sampled individuals, which contains zooplankton that has died for a certain period and been not biodegraded and then drifts freely with the tide. Therefore, the identification of survival rate would be a valuable addition to the traditional zooplankton monitoring to accurately clarify the interactions between water quality and zooplankton ecology in the coastal ecosystem.