Statistical Analysis On The Effect Of Plankton Diversity On Community Stability

The loss of species diversity is more and more rapid due to global climate change and human activities.The effects of species diversity on the functioning of ecosystems and the underlying mechanisms are hot topics in ecology.The health of aquatic ecosystem is closely related to our life.Phytoplankton is the most important primary producer of aquatic ecosystems,and its diversity plays an important role in maintaining community stability.However,the response of community stability to phytoplankton diversity in natural ecosystems has not been determined,and there are still many controversies about the underlying mechanisms.In the present research,the middle temperate mountain rivers and warm temperate freshwater lakes were selected.One is River Taizicheng in the core of the Winter Olympics in Chongli District,Zhangjiakou City,and the other is Lake Nansihu in Shandong Province.Phytoplankton and environmental factors were investigated continuous in the two ecosystems.The temporal-spatial variations of phytoplankton and their influcing environmental factors in River Taizicheng were analyzed.The response of phytoplankton community stability to functional group diversity and environmental factors in Taizicheng River and Nansihu Lake were explored.As a result,the following can be concluded:(1)A total of 69 phytoplankton genera belonging to 6 phyla were identified in River Taizicheng,including 26 Bacillariophyta genera,24 Chlorophyta genera,10 Cyanophyta genera,4 Euglenophyta genera,3 Pyrroptata genera and 2 Cryptophyta genera.Phytoplankton community fluctuated significantly across time during the research.Average phytoplankton density ranged from 4.90×104/L to 6.17×106/L,and mean biomass varied between 0.097mg/L and 16.26mg/L.The species richness,density and biomass of phytoplankton in different sampling sites varied greatly.Results of canonical correspondence analysis(CCA)showed that water temperature(WT),total nitrogen(TN),total phosphorus(TP)and turbidity were the main environmental factors affecting phytoplankton in Taizicheng River.(2)There are 22 phytoplankton functional groups in River Taizicheng.M,MP,J,Y,Lo were the dominate functional groups in the river.The dominant phytoplankton functional groups changed from M,D at August 2018,to M,MP,D,P at October,to MP,Lo,P,D at December,to Lo,MP at February 2019,to Lo,M,H1,MP at April,to M,MP,X3,J,D,W1,B,Lo at June.There were significant differences in the temporal stability index(TSI)of phytoplankton functional groups.The TSI of functional group M was the highest and that of F was the lowest.The number of phytoplankton functional groups had a positive relationship with the TSI of functional group J,a negatively relationship with that of MP,a unimodal relationship with that of F and Y,and a concave relationship with that of W1.Results of CCA showed that the TSI of phytoplankton functional groups was mainly influenced by the number of functional groups and TN concentration.(3)There were 24 phytoplankton functional groups in Nansihu Lake.J,P,D,W1,Tc,X1,X3 were the dominant functional groups.The dominant phytoplankton functional groups varied from J,P,D,W1,Tc at 2011,to J,D,P,X3,W1,Tc at 2012,to J,D,P,W1,B,Tc,XI at 2013.There were significant differences in the TSI of phytoplankton functional groups.The TSI of functional group J was the highest and that of F was the lowest.The number of phytoplankton functional groups had a positive relationship with the TSI of functional group J,a negatively relationship with that of X1 and X3,a unimodal relationship with that of D and Lo,and a concave relationship with that of P.Results of CCA showed that the TSI of different phytoplankton functional groups was mainly affected by the number of functional groups,WT,pH and TN concentrations.The results of the present research will be helpful in understanding the response of phytoplankton stability to functional diversity and environmental factors in different aquatic ecosystems.Besides,it is also helpful to maintain aquatic environment stability,pollution control and protect biodiversity in aquatic ecosystems.