Geochemistry of iron in the Salton Sea, California
- 191 Downloads
- 10 Citations
Abstract
The Salton Sea is a large, saline, closed-basin lake in southern California. The Sea receives agricultural runoff and, to a lesser extent, municipal wastewater that is high in nutrients, salt, and suspended solids. High sulfate concentrations (4× higher than that of the ocean), coupled with warm temperatures and low-redox potentials present during much of the year, result in extensive sulfate reduction and hydrogen sulfide production. Hydrogen sulfide formation may have a dramatic effect on the iron (Fe) geochemistry in the Sea. We hypothesized that the Fe(II)-sulfide minerals should dominate the iron mineralogy of the sediments, and plans to increase hypolimnetic aeration would increase the amount of Fe(III)-oxides, which are strong adsorbers of phosphate. Sequential chemical extractions were used to differentiate iron mineralogy in the lake sediments and suspended solids from the tributary rivers. Iron in the river-borne suspended solids was mainly associated with structural iron within silicate clays (70%) and ferric oxides (30%). The iron in the bottom sediments of the lake was associated with silicate minerals (71% of the total iron in the sediments), framboidal pyrite (10%), greigite (11%), and amorphous FeS (5%). The ferric oxide fraction was <4% of the total iron in these anaerobic sediments. The morphological characteristics of the framboidal pyrite as determined using SEM suggest that it formed within the water column and experiences some changes in local redox conditions, probably associated with alternating summer anoxia and the well-mixed and generally well-aerated conditions found during the winter. The prevalence of Fe(II)-sulfide minerals in the sediments and the lack of Fe(III)-oxide minerals suggest that the classic model of P-retention by Fe(III)-oxides would not be operating in this lake, at least during anoxic summer conditions. Aeration of the hypolimnion could affect the internal loading of P by changing the relative amounts of Fe(II)-sulfides and Fe(III)-oxides at the sediment/water interface.
Keywords
Pyrite Anoxia Saline lake Sulfate reductionSupplementary material
References
- Anderson, M. A., L. Whiteaker, E. Wakefield & C. Amrhein, 2008. Properties and distribution of sediment in the Salton Sea, California: An assessment of predictive models. Hydrobiologia (this issue).Google Scholar
- Berner, R. A., 1970. Sedimentary pyrite formation. American Journal of Science 268: 1–23.CrossRefGoogle Scholar
- Butler, I. B. & D. Rickard, 2000. Framboidal pyrite formation via the oxidation of iron (II) monosulfide by hydrogen sulphide. Geochimica et Cosmochimica Acta 64: 2665–2672.CrossRefGoogle Scholar
- Caraco, N., J. J. Cole & G. E. Likens, 1989. Evidence for sulphate-controlled phosphorous release from sediments of aquatic systems. Nature 341: 316–318.CrossRefGoogle Scholar
- Caraco, N. F., J. J. Cole & G. E. Likens, 1993. Sulfate control of phosphorus availability in lakes. A test and re-evaluation of Hasler and Einsele’s model. Hydrobiologia 253: 275–280.CrossRefGoogle Scholar
- Carroll, D., 1958. Role of clay minerals in the transportation of iron. Geochimica et Cosmochimica Acta 14: 1–28.CrossRefGoogle Scholar
- Cook, C. B., G. T. Orlob & D. W. Huston, 2002. Simulation of wind-driven circulation in the Salton Sea: Implications for indigenous ecosystems. Hydrobiologia 473: 59–75.CrossRefGoogle Scholar
- Cooke, G. D., E. B. Welch, S. A. Peterson & P. R. Newroth, 1993. Restoration and Management of Lakes and Reservoirs, 2nd ed. Lewis Publishers, Boca Raton, FL.Google Scholar
- Cornwell, J. C. & J. W. Morse, 1987. The characterization of iron sulfide minerals in anoxic marine sediments. Marine Chemistry 22: 193–206.CrossRefGoogle Scholar
- Furukawa, Y. & H. L. Barnes, 1995. Reactions forming pyrite from precipitated amorphous ferrous sulphide. In Vairavamurthy, M. A. & M. A. A. Schoonen (eds), Geochemical Transformations of Sedimentary Sulphur. American Chemical Society, 194–204.Google Scholar
- Gleyzes, C., S. Tellier & M. Astruc, 2002. Fractionation studies of trace elements in contaminated soils and sediments: A review of sequential extraction procedures. Trends in Analytical Chemistry 21: 451–467.CrossRefGoogle Scholar
- Golden Software, Inc., 1999. Surfer: A surface mapping system. Version 7. Golden, CO.Google Scholar
- Grossman, R. H., R. S. Liebling & H. S. Scherp, 1979. Chlorite and its relationship to pyritization in anoxic marine environments. Journal of Sedimentary Petrology 49: 611–613.Google Scholar
- Holdren, G. C. & A. Montaño, 2002. Chemical and physical characteristics of the Salton Sea, California. Hydrobiologia 473: 1–21.CrossRefGoogle Scholar
- Hurtgen, M. T., T. W. Lyons, E. D. Ingall & A. M. Cruse, 1999. Anomalous enrichments of iron monosulfide in euxinic marine sediments and the role of H2S in iron sulfide transformations: Examples from Effingham Inlet, Orca Basin and the Black Sea. American Journal of Science 299: 566–588.CrossRefGoogle Scholar
- Ingall, E., L. Kolowith, T. Lyons & M. Hurtgen, 2005. Sediment carbon, nitrogen and phosphorus cycling in an anoxic fjord, Effingham Inlet, British Columbia. American Journal of Science 305: 240–258.CrossRefGoogle Scholar
- Leventhal, J. S. & C. Taylor, 1990. Comparison of methods to determine degree of pyritization. Geochimica et Cosmochimica Acta 54: 2621–2625.CrossRefGoogle Scholar
- Lord, C. J., III, 1982. A selective and precise method for pyrite determination in sedimentary materials. Journal of Sedimentary Petrology 52: 664–666.Google Scholar
- Lyons, T. W., 1997. Sulfur isotopic trends and pathways of iron sulfide formation in upper Holocene sediments of the anoxic Black Sea. Geochimica et Cosmochimica Acta 61: 3367–3382.CrossRefGoogle Scholar
- Mortimer, C. H., 1941. The exchange of dissolved substances between mud and water in lakes (Parts I and II). Journal of Ecology 29: 280–329.CrossRefGoogle Scholar
- Mortimer, C. H., 1942. The exchange of dissolved substances between mud and water in lakes (Parts III and IV). Journal of Ecology 30: 147–201.CrossRefGoogle Scholar
- Nirel, P. M. & F. M. M. Morel, 1990. Pitfalls of sequential extractions. Water Research 24: 1055–1056.CrossRefGoogle Scholar
- Poulton, S. W. & D. E. Canfield, 2005. Development of a sequential extraction procedure for iron: Implications for iron partitioning in continentally derived particulates. Chemical Geology 214: 209–221.CrossRefGoogle Scholar
- Raiswell, R., F. Buckley, R. A. Berner & T. F. Anderson, 1988. Degree of pyritization of iron as a paleoenvironmental indicator of bottom-water oxygenation. Journal of Sedimentary Petrology 58: 812–819.Google Scholar
- Raiswell, R. & D. E. Canfield, 1998. Sources of iron for pyrite formation in marine sediments. American Journal of Science 298: 219–245.CrossRefGoogle Scholar
- Raiswell, R., D. E. Canfield & R. A. Berner, 1994. A comparison of iron extraction methods for the determination of degree of pyritisation and the recognition of iron-limited pyrite formation. Chemical Geology 111: 101–110.PubMedCrossRefGoogle Scholar
- Rickard, D., 1997. Kinetics of pyrite formation by the H2S oxidation of iron(II) monosulfide in aqueous solutions between 25 and 125°C: The rate equation. Geochimica et Cosmochimica Acta 61: 115–134.CrossRefGoogle Scholar
- Rickard, D., M. A. A. Schoonen & G. W. Luther, 1995. Chemistry of iron sulfides in sedimentary environments. In Vairavamurthy, M. A. & M. A. A. Schoonen (eds), Geochemical Transformations of Sedimentary Sulfur. Washington D.C., American Chemical Society Symposium Series 612, 168–193.Google Scholar
- Rodriquez, I. R., C. Amrhein & M. A. Anderson, 2008. Laboratory studies on the coprecipitation of phosphate with calcium carbonate in the Salton Sea, California. Hydrobiologia (this issue).Google Scholar
- Schoonen, M. A. A. 2004. Mechanisms of sedimentary pyrite formation. In Amend, J. P., K. J. Edwards & T. W. Lyons (eds), Sulfur Biogeochemistry: Past and Present. The Geological Society of America Special Paper 379, 117–134.Google Scholar
- Sondegaard, M., J. P. Jensen & E. Jeppesen, 1999. Internal phosphorus loading in shallow Danish Lakes. Hydrobiologia 29: 664–686.Google Scholar
- Sweeney, R. E. & I. R. Kaplan, 1973. Pyrite framboid formation: Laboratory synthesis and marine sediments. Economic Geology 68: 618–634.CrossRefGoogle Scholar
- Tack, F. M. G. & M. G. Verloo, 1995. Chemical speciation and fractionation in soil and sediment heavy metal analysis: A review. International Journal of Environmental Analytical Chemistry 59: 225–238.CrossRefGoogle Scholar
- Tessier, A. & P. G. C. Campbell, 1988. Partitioning of trace metals in sediments. In Kramer, J. R. & H. E. Allen (eds), Metal Speciation: Theory, Analysis and Application. Lewis Publishers, Chelsea, MI, Chapter 9.Google Scholar
- Watts, J. M., B. K. Swan, M. A. Tiffany & S. H. Hurlbert, 2001. Thermal, mixing, and oxygen regimes of the Salton Sea, California, 1997–1999. Hydrobiologia 466: 159–176.CrossRefGoogle Scholar
- Wilkin, R. T., M. A. Arthur & W. E. Dean, 1997. History of water-column anoxia in the Black Sea indicated by pyrite framboid size distributions. Earth and Planetary Science Letters 148: 517–525.CrossRefGoogle Scholar
- Wilkin, R. T. & H. L. Barnes, 1997a. Formation processes of framboidal pyrite. Geochimica et Cosmochimica Acta 61: 323–339.CrossRefGoogle Scholar
- Wilkin, R. T. & H. L. Barnes, 1997b. Pyrite formation in an anoxic estuarine basin. American Journal of Science 297: 620–650.CrossRefGoogle Scholar
- Wilkin, R. T., H. L. Barnes & S. L. Brantley, 1996. The size distribution of framboidal pyrite in modern sediments: An indicator of redox conditions. Geochimica et Cosmochimica Acta 60: 3897–3910.CrossRefGoogle Scholar