Variation of Zooplankton Ecological Group During Spring in China Estuaries

Abstract

Zooplankton was major indicator species of the environment. To explore the effect of marine environment on zooplankton distribution in the coast of China, the zooplankton samples from stations in Guanhe Estuary (GE), Changjiang (Yangtze River) Estuary (CE), Oujiang Estuary (OE), Jiulongjiang Estuary (JE) and Beilun Estuary (BE) (covering 14 latitudes) in spring were surveyed and the variation of zooplankton ecological group was researched. According to the adaptability temperature, the zooplankton was divided into two ecological groups: warm-temperate species and subtropical species. The warm-temperate species was the main dominant species and subtropical species was only dominant species in BE. Calanus sinicus, a warm-temperate species, was the only dominant species in all five estuaries. From north to south, the proportion of warm-temperate species in the five estuaries gradually decreased depends on the number, were 83.33%, 48.39%, 45.00%, 43.75% and 30.43%, respectively. In contrary, the proportion of subtropical species was gradually increased. The warm-temperate species predominated over the total abundance and the percentage was whopping high in the north estuaries, including GE (96.16%), CE (95.57%), OE (97.83%) and JE (95.53%). The abundance percentage of subtropical species have remarkably higher (82.39%) in BE. Five estuaries zooplankton community was subdivided into three zooplankton groups, which were the northern warm temperate zooplankton group, the southern subtropical zooplankton group and the estuarine brackish-water group. The water temperature and coastal current of China Sea are recognized as the main factors determining the distribution and community structure of estuarine zooplankton in spring.