Community Structure Of Zooplankton And Water Quality Characteristics In Typical Mariculture Areas In Guangdong Province

The physiochemical parameters and community structure of zooplankton were studied at 3 sampling stations(Sts.1-3) in Dapeng Cove(May 2007-April 2008) and at 4 sampling stations in Nan'ao,Shantou(May 2007,February 2008-March 2008,December 2008-January 2009). Three depths were sampled,the surface microlayer,the surface layer,and bottom waters.The primary results include:1.85 species of zooplankton were identified in Dapeng Cove.Station-specific totals were 80 (St.1),74(St.2) and 82(St.3) species,respectively.The zooplankton densities changed with seasons.Densities of zooplankton ranged from 1.2-1623.4 ind-L-1 in different water layers. Zooplankton abundance in the mariculture area was significantly less than noted in the control area(p＜0.05).The size-frequency distributions indicated that the frequency of micro-zooplankton(＜0.3 mm) was higher in the mariculture area(0.785) than in the control area(0.540).Hence,small-sized zooplankton were dominant in the mariculture area in Dapeng Cove.2.The average enrichment factors of TN,TP,PO₃-P,SiO₃-Si and DIN in the sea surface microlayer in Dapeng Coce were 1.79±0.17,1.95±0.14,4.68±0.98,1.77±0.12 and 1.58±0.17,respectively.Concentrations of N and P were higher in the mariculture area than in control area while the annual average DO and pH were lower in the mariculture area than in control area,indicating water quality deterioration in the mariculture area.3.67 species of zooplankton were identified in Nan'ao,Shantou.The number of zooplankton in sea surface microlayer was less than observed in the surface layer and bottom waters.The species and abundance of zooplankton in the mariculture area were lower than in noted in the control area.Studies showed that the diel vertical migration(DVM) of zooplankton was pronounced in the shstem.4.Transparency and DO were lower in the Nan'ao,Shantou mariculture area than observed in the control site.The average enrichment factors of TN and TP in the sea surface microlayer were greater than 1 at four sampling stations in the culture lotation.5.The difference in sampling methods affects the estimate of zooplankton species and standing crop,which in turn leads to variable estimates of zooplankton community structure.The glass plate sampling method is better than the sieving method in collecting samples from the sea surface rnicrolayer.