Effect of fluctuating redox conditions on trace metal release from wetland soils from South Carolina and stream sediments from Tennessee
Natural aquatic systems undergo fluctuating redox conditions due to microbial activity, varying water saturation levels, and nutrients dynamics. With fluctuating oxic and anoxic conditions, trace metals can be mobilized or sequestered in response to changes in iron and sulfur speciation and the concentrations and lability of organic carbon. We conducted a systematic laboratory-based microcosm study to examine the effect of redox fluctuations on trace metal mobility in samples collected from two different natural aquatic systems: riparian wetlands and a stream. We incubated water-saturated soils under three cycles of anoxic-oxic conditions (τanoxic:τoxic = 3) spanning 24 days and monitored the change in dissolved and bioavailable metal (copper (Cu), nickel (Ni), zinc (Zn), cobalt (Co), iron (Fe), and manganese (Mn)) concentrations. The dataset includes the results of the variation in metal concentrations due to redox fluctuations in wetland soils and stream sediments. Additionally, the variation in the bioavailable concentration of metals obtained using passive samplers based on diffuse gradient in thin-films technique is included in the dataset. We have also reported the change in the pH values and dissolved oxygen concentrations in the microcosms during the entire study of 24 days. The dataset also contains the dissolved organic carbon and sulfate concentrations, and the data on fractions of metals bound to reducible and oxidizable phases. For materials from both the wetlands and the stream, anoxic conditions favored Co and Zn release, which corresponded with the reductive dissolution of iron oxides. In contrast, dissolved Cu concentrations increased under oxic conditions for both sites and correlated positively with the release of sulfate. In wetland soils, dissolution of Fe (hydr)oxides increased Ni solubility; however, in stream sediments, Ni release occurred when sulfides or organic matter were oxidized. For stream sediments, each subsequent redox cycle increased the bioavailability of trace metals. Upon redox fluctuations in wetland soils, the bioavailability of Zn and Cu increased, whereas bioavailable Ni and Co decreased. This study illustrates that different trace metals display distinct bioavailability patterns during oxic-anoxic fluctuations in natural environments. The biogeochemical cycling of carbon and nitrogen in systems with redox fluctuations may be influenced by these patterns in trace metal availability in addition to the availability of electron donors and acceptors.
- Research Organization:
- Environmental System Science Data Infrastructure for a Virtual Ecosystem (ESS-DIVE) (United States); Trace Metal Dynamics and Limitations on Biogeochemical Cycling in Wetland Soils and Hyporheic Zones
- Sponsoring Organization:
- U.S. DOE > Office of Science > Biological and Environmental Research (BER)
- OSTI ID:
- 1871343
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SURFACE WATER
EARTH SCIENCE > LAND SURFACE > SOILS
EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > WATER QUALITY/WATER CHEMISTRY
EARTH SCIENCE > SOLID EARTH > GEOCHEMISTRY > BIOGEOCHEMICAL PROCESSES
EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > TERRESTRIAL ECOSYSTEMS > WETLANDS > RIPARIANWETLANDS
EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > FRESHWATER ECOSYSTEMS > RIVERS/STREAM
EARTH SCIENCE > BIOSPHERE > ECOLOGICAL DYNAMICS > ECOTOXICOLOGY > BIOAVAILABILITY
EARTH SCIENCE > LAND SURFACE > SOILS > MICRONUTRIENTS/TRACE ELEMENTS
EARTH SCIENCE > LAND SURFACE > SOILS > ORGANIC MATTER