The Spatial And Temporal Variations Of Protozoan Communities And Water Quality Assessment In Xixi Wetland

The community and population dynamics of protozoa were investigated in six different stations of Xixi Wetland, southern China from June 2013 to May 2014. To reveal the relationships between the spatial and temporal patterns of protozoa and the environmental factors, A total of 12 samplings were carried out monthly. Water samples were analyzed and presented as well as environmental variables during the annual investigation. A total of 100 species of protozoa were identified, includind 67 ciliates, 23 sarcodines, 10 flagellates, while the main components were ciliates.The temporal analysis of protozoan communities reveals that(1) in terms of species number, the ciliates were the primarily contributors to the taxonomic compositions of protozoan communities, while the ciliates and flagellates account for a dominant position on abundance. There were 10 dominate spesies: Euglena caudate,Euglena acus, Euglena oxyuris, Cucurbitella mespiliformis, Tintinnopsis wangi,Codonella acutula, Hlateria grandinella, Sphaerophrya soliformis, Strobilidium gyrans, Tintinnidium fluviatile;(2) protozoa exhibited a classic bimodal pattern of seasonal richness in July and December, abundance with maxima in July and May;(3)The species diversity and richness leveled off at a relatively stable and high level in winter, whereas the species richness had a maxima in July;(4) multivariate biota-environment analysis showed the protozoan community structure matched the combination of water temperature, dissolved oxygen, pH and ammonia nitrogen best;(5) Euglena acus, Euglena oxyuris, Cucurbitella mespiliformis, Tintinnopsis wangi,Sphaerophrya soliformis, Strobilidium gyrans, Tintinnidium fluviatile were generally significantly correlated with water temperature, dissolved oxygen, nitrate nitrogen,total phosphorus, total nitrogen.The analysis of spatial patterns of protozoan communities reveals that(1)environmental variables at six sampling stations of Xixi Wetland were spatially different. Stations A and B were most stressed areas by organic pollutants, whereas Station C, D and E were moderately polluted and Station F was less stressed bypollutions;(2) among the six sampling stations, there were highest cumulative abundance and species number at the station A, while the lowest at station D. In terms of relative species number, ciliates were the primarily contributors. Three structure community types could be recognized according to relative abundance:(i) those dominated by ciliates and sarcodines with higher proportions in former(station A and B);(ii) those dominated by ciliates and flagellates with higher contribution of ciliates(station C, D and E); and(iii) those dominated by ciliates and flagellates with high contribution of flagellates(station F);(3) although the species evenness have no obviously difference at six sampling stations, the species diversity and richness were at a relatively high level at the station A and B, the lowest at the station F;(4) five dominant species(Euglena acus, Filamoeba nolandi, Cucurbitella mespiliformis,Codonella acutula and Hemiophrys punctata) were significantly correlated with nutrients NH4-N, NO3-N, NO2-N, TN or TP;(5)spatial patterns of protozoan communities was considerably related to the assemble of dissolved oxygen, ammonia nitrogen, nitrite nitrogen, total phosphorus and total nitrogen.