Temporal and spatial variability of mesozooplankton community in the northern Satsunan area, southern Kyushu

Temporal and spatial variations in the taxonomic composition, standing stocks (abundance and biomass), and protein synthetases activity of the mesozooplankton community in the northern Satsunan area were investigated. Although both variations in sources were significant for their standing stocks, temporal variability was predominant for their protein synthetases activity. A multivariate analysis on their taxonomic compositions identified six groups with large seasonality at the mouth of the Kagoshima Bay and two groups with less temporal variability. These were characterized by calanoids and poecilostomatoids. The mesozooplankton community demonstrated a higher abundance and biomass inside as compared to the outside of the Kagoshima Bay. However, similar protein synthetases activity was seen for both locations. Mesozooplankton protein synthetases activity was high, even when there was a low chlorophyll a average in the sampling layer owing to the increased presence of smaller mesozooplankton. In the sampling layer, individual body mass was lower and mesozooplankton abundance was higher at lower salinity averages. These results suggest that the temporal and spatial variations in the mesozooplankton standing stocks and protein synthetases activity are associated with the advections or extensions of small calanoids and poecilostomatoids with less saline waters.