Development of the microbial communities in lake donghu in relation to water quality

Abstract

There is increasing recognition that protozoa is very useful in monitoring and evaluating water ecological healthy and quality. In order to study the relationship between structure and function of protozoan communities and water qualities, six sampling stations were set on Lake Donghu, a hypereutrophic subtropical Chinese lake. Microbial communities and protists sampling from the six stations was conducted by PFU (Polyurethane foam unit) method. Species number (S), diversity index (DI), percentage of phytomastigophra, community pollution value (CPV), community similarity and heterophy index (HI) were mensurated. The measured indicators of water quality included total phosphorus (TP), dissolved oxygen (DO), Chemical oxygen demand (COD), NH 4 + , NO 2 − and NO 3 − . Every month water samples from stations I, II, III, IV were chemically analyzed for a whole year, Among the chemically analyzed stations, station I was the most heavily polluted, station II was the next, stations III and IV had similar pollution degrees. The variable tendencies of COD, TP, NH 3 , NO 2 − , NO 3 − , and DO during the year was approximately coincident among the six stations. Analysis from the community parameters showed that the pollution of station 0 was much more serious than others, and station V was the most slight. Of the community parameters, CPV and HI were sensitive in reflecting the variables of the water quality. Community similarity index was also sensitive in dividing water qualities and the water quality status of different stations could be correctly classified by the cluster analysis. DI could reflect the tendency of water quality gradient, species number and percentage of Phytomastigophora was not obvious in indicating the water quality gradient.

Concentration and Diversity of Uncultured Legionella spp. in Two Unchlorinated Drinking Water Supplies with Different Concentrations of Natural Organic Matter

“…Apparently, a low concentration of NOM corresponds with greater diversity of Legionella and protozoa species compared to those in water with a high NOM concentration. This inverse relationship between the availability of food or energy sources and genetic diversity is consistent with observations on the diversity of (micro)organisms in natural aquatic environments (18).…”

Phosphorus flux by macrobenthic invertebrates in a shallow eutrophic lake Donghu: spatial change

“…These variations in SRP excretion rates are not only relate to characteristics of individual species/taxa but also reflect the character of environments and primarily trophic conditions in each case study. According to Jiang and Shen (2006), the total direct release rates of phosphorus from sediments vary in different part of lake Donghu from 0.81 to 8.60 mg P·m -2 ·d -1 (or 2-277 µmol P·m -2 ·d -1 ) averaging at 1.99 mg P·m -2 ·d -1 or 64 µmol P·m -2 ·day -1 . We estimate phosphorus excretion rates by benthic invertebrate in 36% of the total direct release from bottom sediment to water after Jiang and Shen (2006).…”

“…According to Jiang and Shen (2006), the total direct release rates of phosphorus from sediments vary in different part of lake Donghu from 0.81 to 8.60 mg P·m -2 ·d -1 (or 2-277 µmol P·m -2 ·d -1 ) averaging at 1.99 mg P·m -2 ·d -1 or 64 µmol P·m -2 ·day -1 . We estimate phosphorus excretion rates by benthic invertebrate in 36% of the total direct release from bottom sediment to water after Jiang and Shen (2006). At the same time, estimated in littoral site of Guozhenghu, maximum SRP excretion rate from benthos (173 µmol P·m -2 ·d -1 ) is a major portion (62%) of the maximum total phosphorus release in this lake.…”

Free-Living Protozoa in Two Unchlorinated Drinking Water Supplies, Identified by Phylogenic Analysis of 18S rRNA Gene Sequences

“…Due to their rapid response to environmental changes, free-living protozoa have been used as water quality indicators, and the diversity in free-living protozoa generally increases with improved water quality (29,(34)(35)(36)45). Consequently, differences in the protozoan communities in the two supplies can be attributed to differences in raw water composition, treatment processes, and conditions in the distribution system (hydraulics, materials, and residence time).…”