Geographical Patterns of Algal Communities Associated with Different Urban Lakes in China

Abstract

Urban lakes play an important role in drainage and water storage, regulating urban microclimate conditions, supplying groundwater, and meeting citizens’ recreational needs. However, geographical patterns of algal communities associated with urban lakes from a large scale are still unclear. In the present work, the geographical variation of algal communities and water quality parameters in different urban lakes in China were determined. The water quality parameters were examined in the samples collected from north, central, south, and coastal economic zones in China. The results suggested that significant differences in water quality were observed among different geographical distribution of urban lakes. The highest total phosphorus (TP)(0.21 mg/L) and total nitrogen (TN) (3.84 mg/L) concentrations were found in XinHaiHu (XHH) lake, it also showed highest the nitrate nitrogen (NO3−-N) (0.39 mg/L),total organic carbon(TOC) (9.77 mg/L), and COD Mn (9.01 mg/L) concentrations among all samples. Environmental and geographic factors also cause large differences in algal cell concentration in different urban lakes, which ranged from 4700 × 104 to 247,800 × 104cell/L. Through light microscopy, 6 phyla were identified, which includes Chlorophyta, Bacillariophyta, Cyanophyta, Dinophyta, Euglenophyta, and Cryptophyta. Meanwhile, the heat map with the total 63 algal community composition at the genus level profile different urban lakes community structures are clearly distinguishable. Further analyses showed that the dominant genera were Limnothrix sp., Synedra sp., Cyclotella sp., Nephrocytium sp., Melosira sp., and Scenedesmus sp. among all samples. The integrated network analysis indicated that the highly connected taxa (hub) were Fragilaria sp., Scenedesmus sp., and Stephanodiscus sp. The water quality parameters of NO3−-N and NH4+-N had significant impacts on the structural composition of the algal community. Additionally, RDA further revealed distinct algal communities in the different urban lakes, and were influenced by NO2−-N, Fe, and algal cell concentrations. In summary, these results demonstrate that the pattern of algal communities are highly correlated with geographic location and water quality on a large scale, and these results also give us further understanding of the complex algal communities and effectively managing eutrophication of urban lakes.

Accumulation of PHA in the Microalgae Scenedesmus sp. under Nutrient-Deficient Conditions

“…In the present work, the production of PHA by Scenedesmus sp., a microalgae strain that had not been previously explored for this purpose, was studied. This strain is commonly found in fresh and brackish waters [ 63 ] in many regions around the world [ 64 ] like North America [ 65 ], China [ 66 ], Thailand [ 67 ], among others. Factors that could potentially impact biopolymer accumulation were identified and their influence was evaluated using a fractional factorial Taguchi experimental design (described in further in Section 2.2 ).…”

Water quality drives the regional patterns of an algal metacommunity in interconnected lakes

“…Besides temperature, the variables strongly related to algal communities were conductivity, COD, and BOD, which concurs with the entire algal community analysis, but that importance differs depending on the location of the lake. Depending on land use and population density along the river, the types and concentrations of organic matter flowing into rivers vary, and the algal communities, which are strongly affected by differences in organic matter, are sensitive to regional differences 34 . This may explain why environmental variables were found to regionally influence the algal community assembly in river-connected lakes.…”

Environmental Drivers of Algal Metacommunity Structure in in River-Connected Lakes

“…Except for temperature, the variables strongly related to algal communities were conductivity, COD, and BOD, which concurs with the entire algal community analysis, but that importance differs depending on the location of the lake. Depending on land use and population density along the river, the types and concentrations of organic matter owing into rivers vary, and the algal communities, which are strongly affected by differences in organic matter, are sensitive to regional differences 26 . This may explain why environmental variables were found to regionally in uence the algal community assembly in river-connected lakes.…”