[Spatiotemporal characteristics of zooplankton community structure and diversity in the strong temperature increment seawaters near Guohua power plant in Xiangshan Bay].

To explore the spatiotemporal characteristics of the zooplankton community structure and diversity in the strong temperature increment seawaters near a power plant, zooplankton samples were seasonally collected in duplicate by the type II net with mesh size of 160 microm at 10 stations near Guohua power plant in Xiangshan Bay in 2011. The results showed that a total of 62 species (including larvae) were identified in the samples, and the average abundance was 9 531.1 ind x m(-3). In the seawaters, zooplankton communities were mainly composed of copepods and pelagic larvae, and pelagic larvae were the dominant with an average percentage of abundance reached up to 66.6%. Analysis of similarities demonstrated that significant differences existed in zooplankton community structures among different months (P < 0.01). In these zooplankton communities, there were 18 dominant species controlling these community structures, among which the most important discriminating species were Centropages tenuiremis, Oithona similis, Oithona fallax, Acartia clausi, Clausocalanus furcatus, Paracalanus aculeatus and Paracalanus parvwus. GLM analysis indicated that diversity indices were also significantly different among different months (P < 0.01). According to the calculation results, the inflection point, where the diversity index began to decrease with increasing water temperature, fell within 20.31-22.31 degrees C. In sections, the average water temperature in the 0.2 km section (D02), away from the outfall, was 2.16: higher than that in the 2 km section. Driven by temperature, the main dominant species such as C. tenuiremis and O. similis tended to move into the 0.2 km section, while A. clause and especially large zooplankton tended to stay away from the outfall, and then gathered in the 1.2 km section. As a result, the number of species (33 species) and abundance (5 522.8 ind x m(-3)) were minimum in the section D02, while the number of species (53 species) and abundance (16 491.0 ind x m(-3)) reached the highest in the 1.2 km section. Meanwhile, diversity indices in the 0.2 km section were also obviously lower than those in other sections. Linear regression analysis showed that the diversity indices significantly decreased with increasing water temperature (P < 0.01). The zooplankton richness decreased by 12.3% when the water temperature increased by 1 degrees C.