Recent sulfur enrichment in the sediments of Little Rock Lake. Wisconsin

Abstract

Multiple sediment cores collected from Little Rock Lake, Wisconsin, prior to experimental acidification show that total sulfur accumulation rates increased during the past century, with most of the increase occurring in the nonacid-volatile inorganic and organic fractions. The increased sulfur accumulation is a result of diagenetic processes within the sediments, rather than changes in seston deposition rates or terrestrial inputs. This enrichment has occurred because atmospheric sulfate deposition rates have increased over the past century, resulting in increased lake-water sulfate concentrations, which has, in turn, increased the diffusional flux to the sediments and increased the extent of diagenetic immobilization. Individual cores had markedly different sulfur accumulation rates, demonstrating the importance of collecting multiple cores to determine lakewide sediment accumulation.Processes that retain sulfate are of considerable interest in the context of lake acidification because they are important in regulating the alkalinity of many soft-water ' Present address: % U.S. EPA Environmental Research Laboratory, 200 SW 35th St., Corvallis, Oregon 97333. AcknowledgmentsWe thank Linda Shane for contributing to the pollen analysis, Peter Appleby for the gamma spectroscopy analysis, and Susan Christie for editorial assistance. The use of the University of Wisconsin's Trout Lake Field Station is appreciated. Carol Kelly, Richard Holdren, and Noel Urban reviewed an earlier draft of this paper and made numerous suggestions.

Sulfur during early diagenesis in Sphagnum peat: Insights from δ34S ratio profiles in 21Pb‐dated peat cores

“…Schell 1987;Urban et al 1989;Baker et al 1992). Moreover, although S accumulation in peat deposits responds to changes in atmospheric S deposition (both along present-day spatial gradients in deposition and in association with temporal changes in historical deposition), over long-term diagenesis, isotopically light S may be continually released from deep peat.…”

“…In both peat deposits and lake sediments, sulfate reduction has been implicated as causing subsurface minima in 634S ratios; however, interpretations based on depth profiles of S fractions and 634S ratios for both lake sediments and peat deposits suggest mobility of S. This apparent mobility brings into question the validity of reconstructing historical records of S accumulation in either lake sediments or peat deposits by combining peat dating techniques with S concentration data (e.g. Schell 1987;Urban et al 1989;Baker et al 1992). Moreover, although S accumulation in peat deposits responds to changes in atmospheric S deposition (both along present-day spatial gradients in deposition and in association with temporal changes in historical deposition), over long-term diagenesis, isotopically light S may be continually released from deep peat.…”

Geochemical processes of iron and manganese in a seasonally stratified lake affected by coal-mining drainage in China

“…The first method was the Tessier five-fraction method: the exchangeable, bound to carbonate, bound to oxides, bound to organic matter, and residue fructions were operationally analyzed (Tessier et al 1979). The second was the Baker method: AVS (acid volatile sulfides, mainly FeS) and FeS 2 were operationally analyzed and calculated by the HCl and Cr 2ϩ method (Baker 1992), and then FeS and FeS 2 were estimated. Simply speaking, the sulfur fractions (FeS and FeS 2 ) were determined with a distillation apparatus consisting of a three-neck distillation flask, condenser, and impinger gas trap filled with 0.5 N Po(NO 3 ) as a trapping solution.…”

Sedimentary and historical context of eutrophication and remediation in urban Lake McCarrons (Roseville, Minnesota)

“…According to the 210 Pb profile, the 1916 horizon is 47.1 cm below the sediment surface in the Engstrom core; by varve counts it occurs at 42.2 cm in core MCC01-1MP. It is well known that sedimentation rates vary across lake basins (e.g., Baker et al 1992). The 210 Pb core was taken some 100-200 m east of core MCC01-1MP, in water ~2 m shallower, and a comparison of the two age models (Fig.…”