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Effects of unstable flow on solute transport in the marsh soil and exchange with coastal water
Author(s) -
Shen Chengji,
Zhang Chenming,
Jin Guangqiu,
Kong Jun,
Li Ling
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl070576
Subject(s) - salt marsh , marsh , hydrology (agriculture) , environmental science , geology , flow (mathematics) , water flow , subsurface flow , brackish marsh , soil water , groundwater , geomorphology , soil science , wetland , oceanography , geotechnical engineering , mechanics , ecology , physics , biology
Recent studies of marsh hydraulics have focused on tide‐induced pore water circulation as the main drive for solute transport in the marsh soil and exchange with coastal water. Our study revealed another important mechanism provided by unstable fingering flow, which largely modified solute transport paths. In the marsh interior, downward penetration of salt fingers forced ambient pore water and solute plumes to move upward and exit the marsh soil through marsh platform at relatively high concentrations, up to 2 orders of magnitude higher than exit solute concentrations at the tidal creek bed. The mixing of solute with ambient pore water in the marsh interior was intensified greatly by fingering flow. A critical distance to the creek was determined based on a field‐scale model simulation to distinguish tidal circulation‐dominated and fingering flow‐dominated solute transport zones. The new transport mechanism has implications for understanding the fate of solutes in particularly salt marshes of low creek densities.