title: Dynamic Coupling of Iron, Manganese, and Phosphorus Behavior in Water and Sediment of Shallow Ice-Covered Eutrophic Lakes.
abstract: Decreasing duration and occurrence of northern hemisphere ice cover due to recent climate warming is well-documented; however, biogeochemical dynamics underneath the ice are poorly understood. We couple time-series analyses of water column and sediment water interface (SWI) geochemistry with hydrodynamic data to develop a holistic model of iron (Fe), manganese (Mn), and phosphorus (P) behavior underneath the ice of a shallow eutrophic freshwater bay. During periods of persistent subfreezing temperatures, a highly reactive pool of dissolved and colloidal Fe, Mn, and P develops over time in surface sediments and bottom waters due to reductive dissolution of Fe/Mn(oxy)hydroxides below the SWI. Redox dynamics are driven by benthic O2 consumption, limited air-water exchange of oxygen due to ice cover, and minimal circulation. During thaw events, the concentration, distribution and size partitioning of all species changes, with the highest concentrations of P and "truly dissolved" Fe near the water column surface, and a relatively well-mixed "truly dissolved" Mn and "colloidal" Fe profile due to the influx of geochemically distinct river water and increased circulation. The partitioning and flux of trace metals and phosphorus beneath the ice is dynamic, and heavily influenced by climate-dependent physical processes that vary in both time and space.
authors.affiliation: †Department of Geology, University of Vermont, Delehanty Hall, 180 Colchester Avenue Burlington, Vermont 05405, United States.|‡Vermont EPSCoR, University of Vermont, Cook Physical Science Building, 82 University Place, Burlington, Vermont 05405, United States.
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Schroth
authors.affiliation: ‡Vermont EPSCoR, University of Vermont, Cook Physical Science Building, 82 University Place, Burlington, Vermont 05405, United States.
authors.forename: Courtney D
authors.initials: CD
authors.lastname: Giles
authors.affiliation: ‡Vermont EPSCoR, University of Vermont, Cook Physical Science Building, 82 University Place, Burlington, Vermont 05405, United States.|§Rubenstein School of Environment and Natural Resources, University of Vermont, Aiken Center, 81 Carrigan Drive, Burlington, Vermont 05405, United States.
authors.forename: Peter D F
authors.initials: PD
authors.lastname: Isles
authors.affiliation: ‡Vermont EPSCoR, University of Vermont, Cook Physical Science Building, 82 University Place, Burlington, Vermont 05405, United States.
authors.forename: Yaoyang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: ∥Department of Geology, Middlebury College, McCardell Bicentennial Hall, 276 Bicentennial Way, Middlebury College, Middlebury, Vermont 05753, United States.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Perzan
authors.affiliation: ⊥Department of Earth Sciences, Indiana University Purdue University, Indianapolis, 723 W. Michigan Street, SL118, Indianapolis, Indiana 46202, United States.
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Druschel
mesh_terms: D002980:Climate; D005068:Eutrophication; D005843:Geography; D019015:Geologic Sediments / Q000737:chemistry*; D057446:Hydrodynamics; D046448:Ice Cover; D007501:Iron / Q000032:analysis*; D060106:Lakes / Q000737:chemistry*; D008345:Manganese / Q000032:analysis*; D010100:Oxygen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis*; D013696:Temperature; D014131:Trace Elements / Q000032:analysis; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D014131:Trace Elements; D014874:Water Pollutants, Chemical; D014867:Water; D010758:Phosphorus; D008345:Manganese; D007501:Iron; D010100:Oxygen