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Spatial Characterization of Hydrogeochemistry Within a Constructed Fen, Greene County, Ohio
Author(s) -
Hite Christopher D.,
Cheng Songlin
Publication year - 1996
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1996.tb02022.x
Subject(s) - alkalinity , environmental chemistry , wetland , organic matter , chemistry , redox , environmental science , groundwater , dissolution , dissolved organic carbon , piezometer , saturation (graph theory) , carbonate , soil science , ecology , aquifer , geology , inorganic chemistry , geotechnical engineering , mathematics , organic chemistry , combinatorics , biology
An artificial fen environment was constructed near the municipality of Beavercreek, Ohio. The constructed wetland environment utilizes local ground‐water flow patterns to maintain a high degree of water saturation. Chemical reactions driven by the activity of plant roots and soil microorganisms affect the spatial distribution and magnitude of hydrogeochemical parameters, including alkalinity, pH, redox potential, and concentrations of Ca +2 , Mg +2 , total iron, NO 3 − , and SO 4 −2 . The purpose of this study is to investigate the chemical interactions between wetland plants and ground water by means of characterizing the spatial variation in hydrogeochemical parameters. Nested piezometers within the artificial fen are used to monitor ground‐water chemistry within, and immediately adjacent to, the rhizosphere of cultivated plant species. The major reactions at the site include oxidation of organic matter by Fe(OH) 3 and dissolution of carbonate minerals driven by high CO 2 production in the root zone. The relationship between alkalinity and dissolved concentrations of Ca +2 and Mg +2 suggests that organic anions could also be major alkalinity contributors. Redox potential is buffered by the reduction of Fe (OH) 3 and is typically maintained in the range of 100–200 mV. This buffering effect prevents the formation of sulfide and methane commonly found in similar wetland environments. This finding suggests that methane production associated with rice cultivation can be prevented by the addition of Fe(OH) 3 to rice fields.