Tidal Pumping Controls Dissolved Organic Matter Properties and Outwelling From Mangrove Groundwater to Coastal Water

Xiao, Kai1,2; Zhang, Peng1,2; Santos, Isaac R.3; Wang, Jun-Jian1,2; Li, Zhenyang1,2; Wang, Xuejing1,2; Wang, Ying-Hui1,2; Lu, Meiqing1,2; Zhang, Licong1,2; Li, Hailong1,2

2023-03-01

10.1029/2022WR033913

WATER RESOURCES RESEARCH   Impact Factor & Quartile

0043-1397

1944-7973

Dissolved organic matter (DOM) in highly productive intertidal mangroves is an important carbon and nutrient source to the coastal ocean. In highly dynamic mangrove intertidal systems, both tidal pumping or geochemical factors can control DOM characteristics. The influence of groundwater flow on DOM properties and fluxes remains poorly understood. Here, we compared the concentrations, sources, and spectroscopic characteristics of DOM across a recharge-discharge gradient. We used a three-dimensional array sampling strategy to reduce spatial biases, groundwater monitoring to quantify tidally driven exchange, and spectrofluoroscopy to quantify DOM fluorescent components. The results showed that tidal hydrology played the key role driving groundwater DOM properties in both horizontal (i.e., from the mangrove to the sea) and vertical directions. Due to the high spatial heterogeneity of dissolved inorganic (DIC) and organic (DOC) carbon concentrations in mangrove groundwater, carbon outwelling showed a high degree of variability at the intertidal scale (54.8-234.8 mu mol m(-2) d(-1) for DIC and 2.5-12.4 mu mol m(-2) d(-1) for DOC). The contribution of terrestrial DOM gradually decreased toward the ocean, but the microbial contributions for recently produced autochthonous DOM increased. Deep groundwater received less terrestrial DOM and experienced anaerobic microbial mineralization, resulting in lower organic carbon than shallow groundwater. Greater variations in spectroscopic characteristics were found in shallow groundwater than in deep groundwater. Overall, tidally driven surface water-groundwater interactions control the variability in DOM properties and how DOM contributes to carbon budgets and sequestration in mangrove groundwater.

blue carbon dissolved organic carbon Submarine groundwater discharge coastal carbon cycle groundwater mangroves

SCI

English

First ; Corresponding

National Natural Science Foundation of China["42177046","41972260","42122054"] ; GuangDong Basic and Applied Basic Research Foundation[2022A1515010572] ; Science, Technology, and Innovation Commission of Shenzhen["JSGG20210802153535002","20200925174525002"]

Environmental Sciences & Ecology ; Marine & Freshwater Biology ; Water Resources

Environmental Sciences ; Limnology ; Water Resources

WOS:000949219200001

AMER GEOPHYSICAL UNION

ENVIRONMENT/ECOLOGY

Web of Science

1.Southern Univ Sci & Technol, Sch Environm Sci & Engn, State Environm Protect Key Lab Integrated Surface, Shenzhen, Peoples R China
2.Southern Univ Sci & Technol, Guangdong Prov Key Lab Soil & Groundwater Pollut C, Shenzhen, Peoples R China
3.Univ Gothenburg, Dept Marine Sci, Gothenburg, Sweden

Xiao, Kai,Zhang, Peng,Santos, Isaac R.,et al. Tidal Pumping Controls Dissolved Organic Matter Properties and Outwelling From Mangrove Groundwater to Coastal Water[J]. WATER RESOURCES RESEARCH,2023,59(3).

Xiao, Kai.,Zhang, Peng.,Santos, Isaac R..,Wang, Jun-Jian.,Li, Zhenyang.,...&Li, Hailong.(2023).Tidal Pumping Controls Dissolved Organic Matter Properties and Outwelling From Mangrove Groundwater to Coastal Water.WATER RESOURCES RESEARCH,59(3).

Xiao, Kai,et al."Tidal Pumping Controls Dissolved Organic Matter Properties and Outwelling From Mangrove Groundwater to Coastal Water".WATER RESOURCES RESEARCH 59.3(2023).