The spatial variations of water quality and effects of water landscape in Baiyangdian Lake, North China.

Liqing Li,Hongjie Wang,Weijun Zhang,Meiyi Zhang,Dongsheng Wang,Xinghong Chen

doi:10.1007/s11356-021-16938-0

Abstract

Baiyangdian Lake (BYD), a large shallow lake in North China, has complex water landscape patterns that are underlies spatial variations in water quality. In this study, we collected 61 water samples from three water landscapes (reed littoral zones, fish ponds, and open water) and analyzed them for water quality parameters, such as dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP). Water landscape distribution (determined using remote sensing imagery) was then used to assess correlations between water quality parameters and water landscape proportion in differently scaled buffer zones. There was substantial variation across all subareas, with TN and TP concentrations ranging from 0.90 to 4.10mg/L and 0.06 to 0.18mg/L, respectively, in class IV of water quality as a whole. Spatial variations in water quality were mainly caused by water landscape distribution and external nutrient inputs. There were negative correlations between DOC, TN, and TP concentrations and the area proportion of reed littoral zones in the 300 and 500m buffers. In contrast, DOC, TN, and TP concentrations were significantly positively correlated with the area proportion of fish ponds in the 100m buffer. Furthermore, compared with reed littoral zones, a lower ratio of nitrogen to phosphorus and a higher proportion of dissolved organic nitrogen and tyrosine-like proteins were found in fish ponds. These effects were mainly attributed to the development of internal sediment loadings due to nutrient exchange across the sediment-water interface. Therefore, dredging-based sediment removal from fish ponds should be considered to suppress internal phosphorus loading and accelerate recovery of the BYD ecosystem.

Highlights

Eutrophication of aquatic ecosystems is a global environmental concern, especially in freshwater lakes (Huisman et al 2018, Tu et al 2019)
We examined correlations between water quality parameters and the area proportion of water landscape types in differently sized buffers
total nitrogen (TN):total phosphorus (TP) was highest for FH (29.5 ± 9.2), followed by open water (19.8 ± 7.8), fish ponds (15.7 ± 6.6), and reed littoral zones (13.2 ± 5.8), and the same trend occurred for DN:DP and NO3−-N:SRP. These results suggested that Baiyangdian Lake (BYD) has the ability to remove incoming nitrogen

Summary

Introduction

Eutrophication of aquatic ecosystems is a global environmental concern, especially in freshwater lakes (Huisman et al 2018, Tu et al 2019). BYD, the largest freshwater lake in the North China Plain, is located in Anxin County, Hebei Province, with an average water depth of 2-3m and an approximate area of 366 km[2] (Wang et al 2014). This area is the planned center of a new special economic zone (the Xiongan New Area), for which the lake is expected to play an important role in supplying fresh water, controlling floods, regulating the local climate, and maintaining biodiversity for the region. Its water quality has been somewhat improved recently through reductions in external nutrient loading and prohibitions on aquaculture, eutrophication remains a problem, especially in summer

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