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Temporal Variations in Dissolved Oxygen Concentrations Observed in a Shallow Floodplain Aquifer
Author(s) -
Schilling K. E.,
Jacobson P. J.
Publication year - 2015
Publication title -
river research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.679
H-Index - 94
eISSN - 1535-1467
pISSN - 1535-1459
DOI - 10.1002/rra.2759
Subject(s) - groundwater recharge , environmental science , hydrology (agriculture) , biogeochemical cycle , floodplain , groundwater , aquifer , precipitation , environmental chemistry , ecology , chemistry , geology , biology , geography , geotechnical engineering , meteorology
Dissolved oxygen (DO) concentrations play an important role in many groundwater biogeochemial processes, yet assessments of temporal variations are lacking. In this study, we examined daily DO concentrations using a continuously‐reading optical DO probe in a shallow floodplain setting in Iowa to (i) quantify fluctuations across two growing seasons; (ii) examine hydrologic controls on DO values; and (iii) model daily DO concentrations using easily measured variables. DO concentrations exhibited both rapid and long‐term changes in concentrations over time, rapidly increasing and decreasing more than 1 mg/l in response to precipitation recharge and stream stage increase over the span of several hours and days. On 40% of the monitoring days in this study, DO concentrations increased, on average, 0.2–0.4 mg/l from one day to the next. DO concentrations decreased approximately 5–6 mg/l from spring through late summer and fall, likely owing to microbial and root respiration. Daily DO concentrations were successfully modelled using a combination of hydrologic (groundwater level and river stage) and temperature variables ( r 2 > 0.7). Improved understanding of temporal controls on groundwater DO patterns is needed to help clarify the dynamics of many biogeochemical processes. Copyright © 2014 John Wiley & Sons, Ltd.