Tidal exchange of dissolved metal(loid)s and organic matters across the sediment–water interface in a salt marsh-mangrove ecotone

Xiao，Kai1,2; Zhang，Licong1; Zhang，Peng1; Wang，Fenfang3; Wang，Junjian1,2; Chen，Nengwang3; Li，Zhenyang1; Pan，Feng3; Lu，Zeyang3; Li，Hailong1,2

2023-07-01

10.1016/j.jhydrol.2023.129665

Journal of Hydrology   影响因子和分区

0022-1694

1879-2707

Coastal wetlands are considered as efficient barriers for pollutants such as dissolved metal(loid)s between land and sea. However, there remains a challenge in understanding how tidal hydrology regulates the source-sink patterns of metal(loid)s across the sediment–water interface, especially in the salt marsh-mangrove ecotone that commonly exists in subtropical coastlines. In this study, we conducted detailed time-series observations of dissolved metal(loid)s (Cr, Cu, Zn, Ba, Pb, Hg, and As) and organic matter (DOM) characteristics (bulk concentrations, aromaticity, and molecular size) in southeast China over a spring-neap tidal cycle. The results demonstrated that both DOM and metal(loid)s fluctuated with tide levels, and higher concentrations exited in groundwater than that in the surface water. The concentrations of bulk DOM and chromophoric DOM both in surface water varied oppositely with tide levels, suggesting the potential role of groundwater discharge at low tides. DOM aromaticity also had tidal time scale fluctuations, but the molecular weight of DOM was insensitive to tide changes. The dispersion fluxes were one to four orders of magnitude lower than advective fluxes with the ranges of 0.14–24.8 μg m d for Cr, 6.2–22.4 μg m d for Cu, 14.7–387.4 μg m d for Zn, 0.7–25.4 μg m d for As, 259.2–2308 μg m d for Ba, 0.1–6.0 μg m d for Pb, 0–1.7 μg m d for Hg and 3.1–116 mg m d for DOM, respectively. Mangrove sediments tended to be the sources of DOM and all dissolved metal(loid)s, but the salt marsh was only the source of Cu, As, and DOM. These results have implications on the geochemical cycling of DOM and dissolved metal(loid)s in the salt marsh-mangrove ecotone which has contrasting pattern of surface water-groundwater exchange.

Advection–diffusion model Blue carbon system Sediment–water interface Tidal creek Trace metals Zhangjiang Estuary

SCI ; EI

英语

第一 ; 通讯

National Natural Science Foun-dation of China[41907162] ; Guangdong Basic and Applied Basic Research Foundation[2022A1515010572] ; Shenzhen Science and Technology Program[JSGG20210802153535002]

Engineering ; Geology ; Water Resources

Engineering, Civil ; Geosciences, Multidisciplinary ; Water Resources

WOS:001011511400001

ELSEVIER

20232214173467

Biogeochemistry ; Carbon ; Dissolution ; Groundwater ; Organic compounds ; Sediments ; Trace elements ; Wetlands

Surface Water:444.1 ; Groundwater:444.2 ; Geochemistry:481.2 ; Soil Mechanics and Foundations:483 ; Biochemistry:801.2 ; Chemical Operations:802.3 ; Chemical Products Generally:804 ; Organic Compounds:804.1

ENGINEERING

2-s2.0-85160576055

Scopus

1.State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen,Guangdong,518055,China
2.Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control,Southern University of Science and Technology,Shenzhen,Guangdong,518055,China
3.Key Laboratory of the Coastal and Wetland Ecosystems,College of the Environment and Ecology,Xiamen University,Xiamen,361102,China

Xiao，Kai,Zhang，Licong,Zhang，Peng,等. Tidal exchange of dissolved metal(loid)s and organic matters across the sediment–water interface in a salt marsh-mangrove ecotone[J]. Journal of Hydrology,2023,622.

Xiao，Kai.,Zhang，Licong.,Zhang，Peng.,Wang，Fenfang.,Wang，Junjian.,...&Li，Hailong.(2023).Tidal exchange of dissolved metal(loid)s and organic matters across the sediment–water interface in a salt marsh-mangrove ecotone.Journal of Hydrology,622.

Xiao，Kai,et al."Tidal exchange of dissolved metal(loid)s and organic matters across the sediment–water interface in a salt marsh-mangrove ecotone".Journal of Hydrology 622(2023).