Chemical features of organic carbon (OC) that foster OC burial in lake sediments

Measurements of S cycling in Little Rock Lake, Wisconsin, and Lake Sempach, Switzerland, are used together with literature data to show the major factors regulating S retention and speciation in sediments. Retention of S in sediments is controlled by rates of seston (planktonic S) deposition, sulfate diffusion, and S recycling. Data from 80 lakes suggest that seston deposition is the major source of sedimentary S for approximately 50% of the lakes; sulfate diffusion and subsequent reduction dominate in the remainder. Concentrations of sulfate in lake water and carbon deposition rates are important controls on diffusive fluxes. Diffusive fluxes are much lower than rates of sulfate reduction, however. Rates of sulfate reduction in many lakes appear to be limited by rates of sulfide oxidation. Much sulfide oxidation occurs anaerobically, but the pathways and electron acceptors remain unknown. The intrasediment cycle of sulfate reduction and sulfide oxidation is rapid relative to rates of S accumulation in sediments. Concentrations and speciation of sulfur in sediments are shown to be sensitive indicators of paleolimnological conditions of salinity, aeration, and eutrophication.

Seston

Deposition

Sulfur Cycle

Geochemical cycle

10.1021/ba-1994-0237.ch010

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Citations (36)

Fractionation of Organic Phosphorus in Lake Sediments

Soil Science Society of America Journal (1972)

L. E. Sommers R. F. Harris J. D. H. Williams David E. Armstrong J. K. Syers

Abstract The organic phosphorus of 10 Wisconsin lake sediments of diverse properties was fractionated on the basis of extractability and anion exchange properties. The fractionation procedure involved sequential extraction of the sediments with 1 N HCl for 1 hour (HCl‐Po), cold 0.3 N NaOH for 16 hours (Cold NaOH‐Po), and hot 0.3 N NaOH for 8 hours (hot NaOH‐Po) followed by anion exchange chromatography of the NaOH extracts into three fractions: fraction I, the 0.3 N NaOH eluate, contained organic P that was not retained by the resin; fraction II, the 0.5 M LiCl eluate, contained organic P with exchange properties similar to inorganic orthophosphate and monophosphate esters; fraction III, the 1 M LiCl + 0.2 N HCl eluate, contained organic P comparable to polyphosphate esters in exchange properties. Total organic P extracted by the fractionation method was comparable to that removed by the standard Mehta et al. extractants indicating that the fractionation method provided valid total organic P data as well as information on the forms of organic P present in sediments. HCl‐Po constituted 6 to 17%, cold NaOH‐Po 60 to 80%, and hot NaOH‐Po 10 to 30% of the total organic P of the sediments. Anion exchange chromatography of the NaOH extracts showed that most of the organic P (48 to 80%) was present in fraction I, the fraction likely composed of high molecular weight humic‐fulvic complexes. Fraction II contained 14 to 36% and fraction III less than 10% of the organic P in the NaOH extracts. Total inositol penta‐ and hexa‐phosphates comprised less than 10% of the total organic P of the sediments. The total and major fractions of sediment organic P were related to organic C, total N and oxalate‐extractable Al, but were not related consistently to any other sediment property or to the trophic level of the lake.

Fraction (chemistry)

Polyphosphate

Ion chromatography

10.2136/sssaj1972.03615995003600010011x

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Citations (68)

Implications of temperature and sediment characteristics on methane formation and oxidation in lake sediments

EGU General Assembly Conference Abstracts (2010)

Nguyen Duc Dung P. M. Crill David Bastviken

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