Abstract: Based on the investigations in the Guanhe Estuary, Changjiang (Yangtze River) Estuary, Oujiang Estuary, Jiaojiang Estuary, Jiulongjiang Estuary and Beilun Estuary (covering 14 latitudes) in April or May of 2010 to 2012, the ecological features of dominant species of the zooplankton assembles in each estuary and underlying mechanisms were analyzed. The result indicated that Calanus sinicus was predominant in all the estuaries. Labidocera euchaeta was the dominant species in the Guhe, Changjiang and Jiaojiang estuaries. Sagitta crassa was the dominant species of Guanhe Estuary, and Tortanus vermiculus was only limited to the Changjiang Estuary. Both S. enflata and Penilia avirostris were the dominant species in the Beilun Estuary. The zooplankton communities of the estuaries were dominated by the warmtemperate species in spring. In addition, temperate species such as S. crassa was also the dominant species in the north (Guanhe Estuary). Warm water species including S. enflata and P. avirostris were the dominant species in the south (Beilun Estuary). All the dominant species are euryhaline.

Key words: apple orchard soil, fertilizing regime, orchard planting age, exchangeable calcium, water-soluble calcium, calcium carbonate