Hydraulic connectivity and evaporation control the water quality and sources of chromophoric dissolved organic matter in Lake Bosten in arid northwest China

TY - JOUR

T1 - Hydraulic connectivity and evaporation control the water quality and sources of chromophoric dissolved organic matter in Lake Bosten in arid northwest China

AU - Zhou, Lei

AU - Zhou, Yongqiang

AU - Hu, Yang

AU - Cai, Jian

AU - Bai, Chengrong

AU - Shao, Keqiang

AU - Gao, Guang

AU - Zhang, Yunlin

AU - Jeppesen, Erik

AU - Tang, Xiangming

PY - 2017/12

Y1 - 2017/12

N2 - Lake Bosten is the largest oligosaline lake in arid northwestern China, and water from its tributaries and evaporation control the water balance of the lake. In this study, water quality and chromophoric dissolved organic matter (CDOM) absorption and fluorescence were investigated in different seasons to elucidate how hydraulic connectivity and evaporation may affect the water quality and variability of CDOM in the lake. Mean suspended solids and turbidity were significantly higher in the upstream tributaries than in the lake, the difference being notably more pronounced in the wet than in the dry season. A markedly higher mean first principal component (PC1) score, which was significantly positively related to protein-like components, and a considerably lower fluorescence peak integration ratio – I C:I T, indicative of the terrestrial humic-like CDOM contribution percentage, were observed in the lake than in the upstream tributaries. Correspondingly, notably higher contribution percentages of terrestrial humic-like components were observed in the river mouth areas than in the remaining lake regions. Furthermore, significantly higher mean turbidity, and notably lower mean conductivity and salinity, were recorded in the southwestern Kaidu river mouth than in the remaining lake regions in the wet season. Notably higher mean salinity is recorded in Lake Bosten than in upstream tributaries. Autochthonous protein-like associated amino-acids and also PC1 scores increased significantly with increasing salinity. We conclude that the dynamics of water quality and CDOM composition in remote arid Lake Bosten are strongly driven by evaporation and also the hydraulic connectivity between the upstream tributaries and the downstream lake.

AB - Lake Bosten is the largest oligosaline lake in arid northwestern China, and water from its tributaries and evaporation control the water balance of the lake. In this study, water quality and chromophoric dissolved organic matter (CDOM) absorption and fluorescence were investigated in different seasons to elucidate how hydraulic connectivity and evaporation may affect the water quality and variability of CDOM in the lake. Mean suspended solids and turbidity were significantly higher in the upstream tributaries than in the lake, the difference being notably more pronounced in the wet than in the dry season. A markedly higher mean first principal component (PC1) score, which was significantly positively related to protein-like components, and a considerably lower fluorescence peak integration ratio – I C:I T, indicative of the terrestrial humic-like CDOM contribution percentage, were observed in the lake than in the upstream tributaries. Correspondingly, notably higher contribution percentages of terrestrial humic-like components were observed in the river mouth areas than in the remaining lake regions. Furthermore, significantly higher mean turbidity, and notably lower mean conductivity and salinity, were recorded in the southwestern Kaidu river mouth than in the remaining lake regions in the wet season. Notably higher mean salinity is recorded in Lake Bosten than in upstream tributaries. Autochthonous protein-like associated amino-acids and also PC1 scores increased significantly with increasing salinity. We conclude that the dynamics of water quality and CDOM composition in remote arid Lake Bosten are strongly driven by evaporation and also the hydraulic connectivity between the upstream tributaries and the downstream lake.

KW - Lake Bosten

KW - Water quality

KW - Chromophoric dissolved organic matter (CDOM)

KW - Hydraulic connectivity

KW - PARALLEL FACTOR-ANALYSIS

KW - BACTERIAL COMMUNITY COMPOSITION

KW - EMISSION MATRIX FLUORESCENCE

KW - OLIGOSALINE LAKE

KW - LAND-USE

KW - MOLECULAR-WEIGHT

KW - SURFACE-SEDIMENT

KW - PARAFAC ANALYSIS

KW - CLIMATE-CHANGE

KW - SALT BALANCE

UR - http://www.scopus.com/inward/record.url?scp=85029288090&partnerID=8YFLogxK

U2 - 10.1016/j.chemosphere.2017.09.006

DO - 10.1016/j.chemosphere.2017.09.006

M3 - Journal article

C2 - 28917213

SN - 0045-6535

VL - 188

SP - 608

EP - 617

JO - Chemosphere

JF - Chemosphere

ER -