| Plankton is the most important primary producer and secondary producer in aquatic ecosystem, which plays an important role in the food chains. Functional groups of phytoplankton and zooplankton as the new method can be used to resolve the ecosystem scientific problems on the food web and energy flow. Therefore, plankton functional groups were need researched in further in water ecosystem.The plankton community compositions and water chemistry indicators were investigated in the Sanjiang plain wetlands in spring (May), summer (July) and autumn (September) of 2014 respectively. The wetlands included 15 sampling sites in Sanhuanpao Wetland and 12 sampling sites in Small Xingkai Lake Wetland. The aim of this study is to reveal the spatiotemporal distribution of plankton functional group composition and their biomass, and also the relationship between the plankton functional groups with environmental factors in typical wetlands of northern cold area.According to the international standards, the phytoplankton can be classified into 20 and 21 functional group separately in the Sanhuanpao Wetland and Small Xingkai Lake Wetland. Based on experts, zooplankton can be divided into seven functional groups in the above both wetlands.The seasonal variation of phytoplankton functional groups was significant. The functional groups of phytoplankton in the Sanhuanpao wetland showed the seasonal variation characteristics of X2+W1â†'?X2+MPâ†'Y+X2+C. Based on the biomass, in spring, the functional group of X2 and W1 were dominant in the Sanhuanpao wetland, especially the biomass proportion of functional group X2 shared over 50% in the site with the highest biomass. However, in summer, X2, MP and H1 were the dominant phytoplankton groups basing on biomass for Sanhuanpao wetland in which MP dominant in 5# and 7# sites, X2 dominant in 4# and 2# sites, X2, and H1 dominant in 6# site. In autumn, the phytoplankton biomass was mainly dominated by functional groups X2, Y and C. C were dominant group in 1# and 2# sites, Y dominant in 6# and 7# sites, and X2 and Y dominant in 8# site with the highest of phytoplankton biomass.The seasonal variation characteristics of phytoplankton functional group in Small Xingkai Lake wetland showed X2+Dâ†'X2+C+H1â†'X2+C. Groups X2 and D were predominant in spring. In spring, X2 was obviously dominant in samples of 8#,10#,11# and 12#, and D dominant in 3# site, and X2 and D dominant in 7# with the highest of phytoplankton biomass. Groups X2, C and H1 were dominant in summer. X2 was dominant in sites of 5#,6#,8# and 11#, C dominant in 2#,9# and 10#, and X2 and H1 dominant in 6# with the highest of phytoplankton biomass. However, in autumn, the dominant group were X2 and C. C was dominant in 1#,2# and 9#, X2 dominant in the other sites. X2 was the most of important phytoplankton functional group in cold region of Small Xingkai Lake wetland, which indicated the habitat wetland was shallow water with moderate or high content of available nutrient and low content of filter feeding zooplankton.We classified zooplankton functional groups in both wetlands in order to study how the zooplankton control the growth of phytoplankton. We investigated zooplankton of Sanhuanpao wetland in different seasons of spring, summer and autumn. The results showed that 7 functional groups were identified during the study period and showed the seasonal tendency of RFâ†'RC+PF+RF+LCCâ†'RC+RF. In spring Group RF was dominant, and significant in samples of 4#,5#,6#,9#,11#,12#,13#and 14#. RC, PF, RF and LCC were dominant in summer. And the sites with different dominant groups, RF in 1#,3# and 4#, LCC in 6# and 9#, and RC in 7#. In autumn, the biomass of zooplankton in Sanhuanpao wetland was lower than other seasons. RC and RF were dominant groups. The highest biomass was sampled in the site of 8# which dominated by RC.The zooplankton functional group in Small Xingkai Lake Wetland showed the variation of MCCâ†'MCFâ†'MCF+MCC. In spring, zooplankton biomass were low for all sampled sites, In spring, MCC accounted for advantage, especially in 1#,3#,5#,9# and 12# sites with more than 70% proportion. The highest biomass of zooplankton was sampled in 1# and MCC are dominant group. In summer, the zooplankton biomass changed significant higher. And the dominant group was MCF, with the exception of 4#,8#,11# and 12# sites, In autumn, the planktonic biomass was low again, but MCF was still the dominant group in 7# with the highest biomass.Nutrients, water temperature and water dynamics were the main influencing factors for the functional groups of plankton. Then main factors were significantly different in Sanhuanpao and Small Xingkai Lake wetland. Although transparency and turbidity are major environmental factors affecting the two wetland phytoplankton functional groups, but turbidity in Small Xingkai Lake was significantly higher than that of Sanhuanpao wetland, while transparency lower than Sanhuanpao wetland. The high turbidity in Sanhuanpao wetland was mainly caused by phytoplankton growth, while turbidity mainly due to the upstream runoff and sediment small in Xingkai Lake Wetland, In Sanhuanpao wetland, turbidity was positively, but transparency negatively related with the phytoplankton functional groups. And the relationship was opposite for the Small Xingkai Lake. Water temperature was the main environmental factor for phytoplankton functional groups in Sanhuanpao wetland, but has a little influence in the small Xingkai Lake. The total inorganic carbon (IC) was significantly higher in Sanhuanpao wetland than those in the small Xingkai Lake, In the small Xingkai Lake, IC was significantly positively correlated with Y and C, negatively correlated with MP and X2. But in Small Xingkai Lake found no significant correlation with phytoplankton functional groups. The difference of total organic carbon (TOC) was not obvious in two wetland water bodies, and TOC had no significant effect on the functional groups of phytoplankton in the two wetland protected areas.TN was the main factor affecting phytoplankton functional group in Sanhuanpao wetland reserve, while TP was the most important factor impacting phytopalnkton functional group in Small Xingkai Lake. The effects of total nitrogen (TN) and total phosphorus (TP) on phytoplankton and zooplankton function groups were consistent in Sanhuanpao wetland and Small Xingkai Lake Wetland, indicating that the total nitrogen, total phosphorus affected zooplankton mainly through the effects on the growth of phytoplankton. Transparency and turbidity had the same effects on zooplankton functional groups in two wetlands. Except the functional group PF, turbidity showed the positive correlation with zooplankton, while transparency negative correlation with zooplankton. IC significantly affected the zooplankton functional groups in Sanhuanpao wetland, but no significant effect in Small Xingkai Lake. TOC had no significant effect on zooplankton in two wetlands.According to the phytoplankton biomass, the dominant phytoplankton functional groups and Q index of phytoplankton functional groups, Sanhuanpao wetland was in middle pollution-light pollution state. Small Xingkai Lake Wetland was in middle pollution-light pollution state, except for the site of 6 # in summer, and belong to middle pollution in spring and summer, the fall in light pollution. In this paper, we illustrated the plankton functional group composition and the spatial and temporal distribution characteristics, and also the relationship between the functional groups and environmental factors in the typical wetlands of the Sanjiang Plain. We also evaluated the pollution state of Sanjiang Plain wetlands using the Q pollution index basing on phytoplankton functional groups. The studies in this paper provided the basis for the wetland water environment protection and wetland protection and comprehensive management. |
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