Sulfide release from estuarine sediments underlying anoxic bottom water

Abstract

Independent measurements of dissolved sulfide (DS) production in and release from mesohaline Chesapeake Bay sediments underlying anoxic bottom water were made during summer. DS accumulated under benthic chambers at a rate of 27.3rt8.2 mmol m-2 d-l. Rates of DS release ranged from 60 to 80% ofdepth-integrated@-12 cm) sulfate reduction (SR) rates (average 39.Ok9.0 mmol m-2 d-l) determined with 35S0, 2 -. The balance between DS production, accumulation in pore waters, and sediment-water exchange was examined by steady siate and transient state transport-reaction modeling, with a DS sediment diffusion coefficient derived from that determined for sulfate by the instantaneous source technique. The results indicate that DS transport is influenced by processes other than vertical molecular diffusion, most likely gas bubble ebullition driven by methane production beneath the SR zone. Although such processes may significantly reduce porewater DS accumulation (i.e. promote DS release), the models show that most (65-95%) DS formation during summer is not stored in the DS pool regardless of the transport processes occurring. The observed rates of DS production and release correspond to a potential oxygen demand of l-2 g 0, m-z d-l, equal to or greater than estimated rates of eddy-diffusive bottom-water reaeration during summer stratification. Thus, sulfur cycling alone can maintain anoxia in these subpycnocline waters during summer under quiescent water conditions. Anoxic sediment metabolism is a quantitatively significant component of the carbon cycle in shallow-water aquatic ecosystems (Jorgensen 1983), and sulfate reduction (SR) is the principal terminal microbial process in anoxic sediments where sulfate is abundant (Capone and Kiene 1988). The reoxidation of reduced sulfur formed by SR influences oxygen balance in shallow coastal systems, accounting for at least half of sediment oxygen consumption (SOC) under waters <20 m deep (Jorgensen 1982). In coastal systems subject to vertical water stratification, SOC linked to sulfur cycling I Current address: 430 National Center, U.S. Geological Survey, Reston, Virginia 22092. AcknowledgmentsThis research was supported by NSF grant OCE 82-08032 and NOAA Sea Grant Project R/DO-9 (awarded to J. H. Tuttle), and NSFgrant SR 88-14272 (awarded to D. G. Capone).We are indebted to W. M. Kemp, W. R. Boynton, P. A. Sampou, and J. M. Barnes for deploying the benthic chambers, to C. L. Divan for performing sulfide analyses during the flux measurements, and to D. Capone and M. Marvin for permission to present unpublished data. We also thank Jeffrey Chanton and two anonymous reviewers for reviewing the manuscript.Contribution 2276 from the Center for Environmental and Estuarine Studies, University of Maryland.

Contribution of Streptomyces in sediment to earthy odor in the overlying water in Xionghe Reservoir, China

“…considerably lower than the release of dissolved sulfide from sedimentsdup to 39.0 mmol m À2 d À1 (Roden and Tuttle, 1992). On the basis of the above results, we can conclude that geosmin in the overlying water of Xionghe Reservoir originates from the geosmin released from sediments.…”

Effects of cyanobacterial-driven pH increases on sediment nutrient fluxes and coupled nitrification-denitrification in a shallow fresh water estuary

“…In the deep, anoxic region of the Chesapeake Bay and other estuaries, phosphorus flux is usually promoted by the dissolution of Fe-oxides and their conversion to iron sulfides (Cornwell and Sampou, 1995;Roden and Tuttle, 1992). The increase in ammonium release from sediments tends to coincide with inhibition of nitrification by oxygen depletion and generation of reductants (HS − /H 2 S) in sediment, which consequently constrain denitrification (Kemp et al, 2005;Cornwell et al, 1999).…”

Benthic sulfate reduction along the Chesapeake Bay central channel. II. Temporal controls

“…(3) based on 1 previous assessment of D s(25) at a nearby mesohaline site (Roden & Tuttle 1992). However, even if the actual diffusion coefficient value at Site MB (at 25°C) is 50% greater than the measurement by Roden & Tuttle (1992;i.e ), then the estimate of how much total SR is directly supported by SO 4 2 -diffusion for the May to July low period would only increase from an average of 8.6 to 13.0%. Thus, our conclusion would remain unchanged regarding this period, as being a particularly important time for Srecycling supporting SR.…”

“…The latter process is largely responsible for bottom water hypoxia/anoxia in Chesapeake Bay (Roden & Tuttle 1992), which is ultimately driven by system eutrophication leading to enhanced autochthonous production and enhanced microbial respiration. Hypoxia/anoxia has long been recognized as a problem in this and other estuaries (Seliger et al 1985, Summers et al 1997, as low dissolved oxygen conditions have negative repercussions, both aesthetically and with respect to the survival of estuarine biota (Holland 1985, Breitburg et al 1997.…”

“…An average MB φ of 0.9 was used in all calculations. Values for D s(T ) were calculated using D s = 0.43 cm 2 d -1 at 25°C, which was previously measured at a nearby (> 0.5 km) mesohaline site (R64E) (Roden & Tuttle 1992) (Jørgensen 1978b), and assuming the relationship:…”