Spatial Characterization of Hydrogeochemistry Within a Constructed Fen, Greene County, Ohio

Abstract

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, NO3−, and SO4−2. 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 CO2 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.

Behavior of Cinosulfuron in Paddy Surface Waters, Sediments, and Ground Water

“…The paddy water pH varied considerably during the two years of the study (Table 2) The initial mean values of 6.3 (1997) and 6.9 (1998) rose to more than 8 after 28 d of treatment with cinosulfuron in 1997 (after 42 d in 1998), and then virtually fell to the starting values after 64 d. These fluctuations are most likely related to the variations of soil pH, as a consequence of the soil flooding conditions (Sequi, 1989), and to daily water pH variations, due to the photosynthetic processes (Hite and Cheng, 1996).…”

Upland Controls on the Hydrological Functioning of Riparian Zones in Glacial Till Valleys of the Midwest1

“…, 2004). Phosphorus chemistry is sensitive to redox conditions in soil, which are strongly influenced by water table fluctuations and biological activity (Hite and Cheng, 1996). Peterjohn and Correll (1984) also noted the importance of understanding site hydrology to understand P exports through riparian systems by investigating the relative importance of ground‐water flow and overland flow on phosphorus transport.…”

“…The occurrence of denitrification has been linked to water table fluctuation, which affects the amount of oxygen available in the soil (Devito et al, 2000;Gold et al, 2001;Burt et al, 2002;Hefting et al, 2004). Phosphorus chemistry is sensitive to redox conditions in soil, which are strongly influenced by water table fluctuations and biological activity (Hite and Cheng, 1996). Peterjohn and Correll (1984) also noted the importance of understanding site hydrology to understand P exports through riparian systems by investigating the relative importance of ground-water flow and overland flow on phosphorus transport.…”

A Field Study on the Hydrochemistry of Land/Inland Water Ecotones with Reed Domination

“…Eser and Rosen [11] studied the hydrochemistry of Stump Bay wetland and found that the reduction of ferric iron determines many hydrochemical variations in the groundwater. Hite and Cheng [12] investigated the chemical interactions between wetland plants and groundwater by characterizing the spatial variation in hydrogeochemical parameters and showed that the reactions determined by the activity of plant roots and soil microorganisms can affect the spatial distribution of hydrogeochemical parameters. The hydrochemical gradients of the aquatic-terrestrial interface can greatly determine the purification efficiency of wetland ecosystems [13].…”