Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 6 7 2009 10.5194/bg-6-1273-2009 http://www.biogeosciences.net/6/1273/2009/ http://www.biogeosciences.net/6/1273/2009/bg-6-1273-2009.html http://www.biogeosciences.net/6/1273/2009/bg-6-1273-2009.pdf 1273 1293 2009-07-28 Coastal hypoxia and sediment biogeochemistry J. J. Middelburg j.middelburg@nioo.knaw.nl L. A. Levin Netherlands Institute of Ecology (NIOO-KNAW), Korringaweg 7, 4401 NT Yerseke, The Netherlands Faculty of Geosciences, Utrecht University, P.O. Box 80021, 3508 TA Utrecht, The Netherlands Integrative Oceanography Division, Scripps Inst. of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093-0218, USA The intensity, duration and frequency of coastal hypoxia (oxygen concentration <63 μM) are increasing due to human alteration of coastal ecosystems and changes in oceanographic conditions due to global warming. Here we provide a concise review of the consequences of coastal hypoxia for sediment biogeochemistry. Changes in bottom-water oxygen levels have consequences for early diagenetic pathways (more anaerobic at expense of aerobic pathways), the efficiency of re-oxidation of reduced metabolites and the nature, direction and magnitude of sediment-water exchange fluxes. Hypoxia may also lead to more organic matter accumulation and burial and the organic matter eventually buried is also of higher quality, i.e. less degraded. Bottom-water oxygen levels also affect the organisms involved in organic matter processing with the contribution of metazoans decreasing as oxygen levels drop. Hypoxia has a significant effect on benthic animals with the consequences that ecosystem functions related to macrofauna such as bio-irrigation and bioturbation are significantly affected by hypoxia as well. Since many microbes and microbial-mediated biogeochemical processes depend on animal-induced transport processes (e.g. re-oxidation of particulate reduced sulphur and denitrification), there are indirect hypoxia effects on biogeochemistry via the benthos. Severe long-lasting hypoxia and anoxia may result in the accumulation of reduced compounds in sediments and elimination of macrobenthic communities with the consequences that biogeochemical properties during trajectories of decreasing and increasing oxygen may be different (hysteresis) with consequences for coastal ecosystem dynamics. Aller, R. C.: Quantifying solute distributions in the bioturbated zone of marine sediments by defining an average micro environment, Geochim. Cosmochim. Ac., 44, 1955–1965, 1980. Aller, R. C.: The importance of relict burrow structures and burrow irrigation in controlling sedimentary solute distributions, Geochim. Cosmochim. Ac., 48, 1929–1934, 1984. Aller, R. C.: Bioturbation and remineralization of sedimentary organic matter – Effects of redox oscillation, Chem. Geol., 114, 331–345, 1994. Aller, R.C. : Transport and reactions in the bioirrigated zone, in: The benthic boundary layer: transport processes and biogeochemistry, edited by: Boudreau, B. P. and Jørgensen, B. B., pp 269–301, 2001. Aller, R. C. and Rude, P. D.: Complete oxidation of solid-phase sulphides by manganese and bacteria in anoxic marine sediments, Geochim. Cosmochim. Ac., 52, 751–765, 1988. Aller, R. C. and Yingst, J. Y.: Effects of the marine deposit feeders Heteromastus-Filiformis (Polychaeta), Macoma-Balthica (Bivalvia), and Tellina-Texana (Bivalvia) on averaged sedimentary solute transport, reaction rates, and microbial distributions, J. Mar. Res., 43, 615–645, 1985. Aller, R. C. and Aller, J. Y.: The effect of biogenic irrigation intensity and solute exchange on diagenetic reaction rates in marine sediments, J. Mar. Res., 56, 905–936, 1998. Anderson, J. J. and Devol, A. H.: Extent and intensity of the anoxic zone in basins and fjords, Deep-Sea Res. Pt. I, 34, 927–944, 1987. Anderson, T. F. and Raiswell, R.: Sources and mechanisms for the enrichment of highly reactive iron in euxinic Black Sea sediments, Am. J. Sci., 304, 203–233, 2004. Andersson, J. H., Woulds, C., Schwartz, M., Cowie, G. L., Levin, L. A., Soetaert, K., and Middelburg, J. J.: Short-term fate of phytodetritus in sediments across the Arabian Sea Oxygen Minimum Zone, Biogeosciences, 5, 43–53, 2008. Archer, D. and Devol, A.: Benthic oxygen fluxes on the Washington Shelf and Slope – a comparison of I in situ microelectrode and chamber flux measurements, Limnol. Oceanogr., 37, 614–629, 1992. Bagarinao, T.: Sulphide as an environmental factor and toxicant: tolerance and adaptations in aquatic organisms, Aquat. Toxicol., 24, 21–62, 1992. Berner, R. A.: Early diagenesis: A theoretical approach, Princeton Univ. Press, 1980. Berner, R. A.: Sedimentary pyrite formation – an update, Geochim. Cosmochim. Ac., 48, 605–615, 1984. Berner, R. A. and Westrich, J. T.: Bioturbation and the early diagenesis of carbon and sulphur, Am. J. Sci., 285, 193–206, 1985. Bernhard, J. M., Buck, K. R., Farmer, M. A., and Bowser, S. S.: The Santa Barbara Basin is a symbiosis oasis, Nature, 403, 77–80, 2000. Boetius, A., Ravenschlag, K., Schubert, C. J., Rickert, D., Widdel, F., Gieseke, A., Amann, R., Jorgensen, B. B., Witte, U., and Pfannkuche, O.: A marine microbial consortium apparently mediating anaerobic oxidation of methane, Nature, 407, 623–626, 2000. Bouldin, D. R.: Models for describing diffusion of oxygen and other mobile constituents across mud-water interface, J. Ecol., 56, 77–87, 1968. Breitburg, D. L., Pihl, L., and Kolesar, S. E.: Effects of low dissolved oxygen on the behavior, ecology and harvest of fishes: A comparison of the Chesapeake Bay and Baltic-Kattegat Systems, in: Coastal and Estuarine Studies: Coastal Hypoxia Consequences for Living Resources and Ecosystems, edited by: Rabalais, N. N. and Turner, R. E., American Geophysical Union, Washington, D. C., 293–310, 2001. Brüchert, V., Jorgensen, B. B., Neumann, K., Riechmann, D., Schlosser, M., and Schulz, H.: Regulation of bacterial sulphate reduction and hydrogen sulphide fluxes in the central Namibian coastal upwelling zone, Geochim. Cosmochim. Ac., 67, 4505–4518, 2003. Brüchert, V.: Early diagenesis of sulfur in estuarine sediments: The role of sedimentary humic and fulvic acids, Geochim. Cosmochim. Ac., 62, 1567–1586, 1998. Burdige D. : Geochemistry of Marine Sediments, Princeton University Press, 2006. Burkholder, J. M., Tomasko, D. A., and Touchette, B. W.: Seagrasses and eutrophication, J. Exp. Mar. Biol. Ecol., 350, 46–72, 2007. Cai, W. J. and Reimers, C. E.: Benthic oxygen flux, bottom water oxygen concentration and core top organic carbon content in the deep northeast Pacific Ocean, Deep-Sea Res. Pt. I, 42, 1681–1699, 1995. Canfield, D. E., Jorgensen, B. B., Fossing, H., Glud, R., Gundersen, J., Ramsing, N. B., Thamdrup, B., Hansen, J. W., Nielsen, L. P., and Hall, P. O. J.: Pathways of organic-carbon oxidation in 3 continental margin sediments, Mar. Geol., 113, 27–40, 1993. Canfield, D. E.: Factors Influencing organic carbon preservation in marine sediments, Chem. Geol., 114, 315–239, 1994. Canfield, D. E.: Sulphate reduction and oxic respiration in marine sediments – Implications for organic carbon preservation in euxinic environments, Deep-Sea Res. Pt. I, 36, 121–138, 1989. Childress, J. J. and Seibel, B. A.: Life at stable low oxygen levels: adaptations of animals to oceanic oxygen minimum layers, J. Exp. Biol., 201, 1223–1232, 1998. Childs, C. R., Rabalais, N. N., Turner, R. E., and Proctor, L. M.: Sediment denitrification in the Gulf of Mexico zone of hypoxia, Mar. Ecol.-Prog. Ser., 240, 285–290, 2002. Cloern, J. E.: Our evolving conceptual model of the coastal eutrophication problem, Mar. Ecol.-Prog. Ser., 210, 223–253, 2001. Conley, D. J., Carstensen, J., Aertebjerg, G., Christensen, P. B., Dalsgaard, T., Hansen, J. L. S., and Josefson, A. B.: Long-term changes and impacts of hypoxia in Danish coastal waters, Ecol. Appl., 17, 165–184, 2007. Conley, D. J., Humborg, C., Rahm, L., Savchuk, O. P., and Wulff, F.: Hypoxia in the Baltic Sea and basin-scale changes in phosphorus biogeochemistry, Environ. Sci. Technol., 36, 5315–5320, 2002. Conley, D. J., Bjorck, S., Bonsdorff, E., Carstensen, J., Destouni, G., Gustafsson, B. G., Hietanen, S., Kortekaas, M., Kuosa, H., Meier, H. E. M., Muller-Karulis, B., Nordberg, K., Norkko, A., Nurnberg, G., Pitkanen, H., Rabalais, N. N., Rosenberg, R., Savchuk, O. P., Slomp, C. P., Voss, M., Wulff, F., and Zillen, L.: Hypoxia-related processes in the Baltic Sea, Environ. Sci. Technol., 43, 3412–3420, 2009. Cowan, J. L. W. and Boynton, W. R.: Sediment-water oxygen and nutrient exchanges along the longitudinal axis of Chesapeake Bay: Seasonal patterns, controlling factors and ecological \mboxsignificance, Estuaries, 19, 562–580, 1996. Cowie, G.: The biogeochemistry of Arabian Sea surficial sediments: A review of recent studies, Prog. Oceanogr., 65, 260–289, 2005. Cowie, G. L., Mowbray, S., Lewis, M., Matheson, H., and McKenzie, R.: Carbon and nitrogen elemental and stable isotopic compositions of surficial sediments from the Pakistan margin of the Arabian Sea, Deep-Sea Res. Pt. II, 56, 271–282, 2009. Cowie, G. L., Hedges, J. I., and Calvert, S. E.: Sources and relative reactivities of amino acids, neutral sugars, and lignin in an intermittent anoxic marine environment, Geochim. Cosmochim. Ac., 56, 1963–1978, 1992. Damsté, J. S. S. and de Leeuw, J. W.: Analysis, structure and geochemical significance of organically-bound sulphur in the geosphere: state of the art and future research, Org. Geochem., 16, 1077–1101, 1990. Damsté, J. S. S., Rijpstra, W. I. C., and Reichart, G. J.: The influence of oxic degradation on the sedimentary biomarker record II, Evidence from Arabian Sea sediments, Geochim. Cosmochim. Ac., 66, 2737–2754, 2002. Damsté, J. S. S., Wakeham, S. G., Kohnen, M. E. L., Hayes, J. M., and Deleeuw, J. W.: A 6000-Year sedimentary molecular record of chemocline excursions in the Black Sea, Nature, 362, 827–829, 1993. Dauer, D. M., Rodi, A. J., and Ranasinghe, J. A.: Effects of low dissolved oxygen events on the macrobenthos of the Lower Chesapeake Bay, Estuaries, 15, 384–391, 1992. Dauwe, B., Middelburg, J. J., and Herman, P. M. J.: Effect of oxygen on the degradability of organic matter in subtidal and intertidal sediments of the North Sea area, Mar. Ecol.-Prog. Ser., 215, 13–22, 2001. Dauwe, B., Middelburg, J. J., Herman, P. M. J., and Heip, C. H. R.: Linking diagenetic alteration of amino acids and bulk organic matter reactivity, Limnol. Oceanogr., 44, 1809–1814, 1999. Demaison, G. J. and Moore, G. T.: Anoxic environments and oil source bed genesis, AAPG Bull.-Am. Assoc. Petr. Geol., 64, 1179–1209, 1980. Diaz, R.: Overview of hypoxia around the world, J. Environ. Qual. 30, 275–281, 2001. Diaz, R. J. and Rosenberg, R.: Marine benthic hypoxia: A review of its ecological effects and the behavioural responses of benthic macrofauna, London, Ann. Rev. Ocean. Mar. Biol., 33, 245–303, 1995. Diaz, R. J. and Rosenberg, R.: Spreading dead zones and consequences for marine ecosystems, Science, 321, 926–929, 2008. Duarte, C. M.: Submerged Aquatic Vegetation in Relation to Different Nutrient Regimes, Ophelia, 41, 87–112, 1995. Eldridge, P. M. and Morse, J. W.: Origins and temporal scales of hypoxia on the Louisiana shelf: Importance of benthic and sub-pycnocline water metabolism, Mar. Chem., 108, 159–171, 2008 Emmerson, M. C., Solan, M., Emes, C., Paterson, D. M., and Raffaelli, D.: Consistent patterns and the idiosyncratic effects of biodiversity in marine ecosystems, Nature, 411, 73-77, 2001. Ferdelman, T. G., Church, T. M., and Luther, G. W.: Sulfur enrichment of humic-substances in a Delaware saltmarsh sediment core, Geochim. Cosmochim. Ac., 55, 979–988, 1991. Ferro, I., Van Nugteren, P., Middelburg, J. J., Herman, P. M. J., and Heip, C. H. R.: Effect of macrofauna, oxygen exchange and particle reworking on iron and manganese sediment \mboxbiogeochemistry: A laboratory experiment, Vie Milieu, 53, 211–220, 2003. Friedl, G., Dinkel, C., and Wehrli, B.: Benthic fluxes of nutrients in the northwestern Black Sea, Mar. Chem., 62, 77–88, 1998. Forster, S., Graf, G., Kitlar, J., and Powilleit, M.: Effects of bioturbation in oxic and hypoxic conditions – a microcosm experiment with a North Sea sediment community, Mar. Ecol.-Prog. Ser., 116, 153–161, 1995. Glazer, B. T., Luther, G. W., Konovalov, S. K., Friederich, G. E., Trouwborst, R. E., and Romanov, A. S.: Spatial and temporal variability of the Black Sea suboxic zone, Deep-Sea Res. Pt. II, 53, 1756–1768, 2006. Glud, R. N.: Oxygen dynamics of marine sediments, Mar. Biol. Res., 4, 243–289, 2008. Gooday, A. J., Jorissen, F., Levin, L. A., Middelburg, J. J., Naqvi, S. W. A., Rabalais, N. N., Scranton, M., and Zhang, J.: Historical records of coastal eutrophication-induced hypoxia, Biogeosciences Discuss., 6, 2567–2658, 2009. Grantham, B. A., Chan, F., Nielsen, K. J., Fox, D. S., Barth, J. A., Huyer, A., Lubchenco, J., and Menge, B. A.: Upwelling-driven nearshore hypoxia signals ecosystem and oceanographic changes in the northeast Pacific, Nature, 429, 749–754, 2004. Gray, J. S., Wu, R. S. S., and Or, Y. Y.: Effects of hypoxia and organic enrichment on the coastal marine environment, Mar. Ecol.-Prog. Ser., 238, 249–279, 2002. Gutierrez, D., Gallardo, V. A., Mayor, S., Neira, C., Vasquez, C., Sellanes, J., Rivas, M., Soto, A., Carrasco, F., and Baltazar, M.: Effects of dissolved oxygen and fresh organic matter on the bioturbation potential of macrofauna in sublittoral sediments off Central Chile during the 1997/1998 El Nino, Mar. Ecol.-Prog. Ser., 202, 81–99, 2000. Gutierrez, D., Enriquez, E., Purca, S., Quipuzcoa, L., Marquina, R., Flores, G., and Graco, M.: Oxygenation episodes on the continental shelf of central Peru: Remote forcing and benthic ecosystem response, Prog. Oceanogr., 79, 177–189, 2008. Hargrave, B. T., Holmer, M., and Newcombe, C. P.: Towards a classification of organic enrichment in marine sediments based on biogeochemical indicators, Mar. Pollut. Bull., 56, 810–824, 2008. Hartnett, H. E. and Devol, A. H.: Role of a strong oxygen-deficient zone in the preservation and degradation of organic matter: A carbon budget for the continental margins of northwest Mexico and Washington State, Geochim. Cosmochim. Ac., 67, 247–264, 2003. Hartnett, H. E., Keil, R. G., Hedges, J. I., and Devol, A. H.: Influence of oxygen exposure time on organic carbon preservation in continental margin sediments, Nature, 391, 572–574, 1998. Hedges, J. I. and Keil, R. G.: Organic geochemical perspectives on estuarine processes: sorption reactions and consequences, Mar. Chem., 65, 55–65, 1999. Hedges, J. I. and Keil, R. G.: Sedimentary Organic-Matter Preservation – an Assessment and Speculative Synthesis, Mar. Chem., 49, 81–115, 1995. Heip, C. H. R., Goosen, N. K., Herman, P. M. J., Kromkamp, J., Middelburg, J. J., and Soetaert, K.: Production and consumption of biological particles in temperate tidal estuaries, London, Ann. Rev. Ocean. Mar. Biol., 33, 1–150, 1995. Herman, P. M. J., Middelburg, J. J., Van de Koppel, J., and Heip, C. H. R.: Ecology of estuarine macrobenthos, Adv. Ecol. Res., 29, 195–240, 1999. Hietanen, S. and Lukkari, K: The effect of short-term anoxia on benthic denitrification, nutrient fluxes, and phosphorus forms in the sediment, Aquat. Microb. Ecol. 49, 293–302, 2007. Hoefs, M. J. L., Rijpstra, W. I. C., and Damste, J. S. S.: The influence of oxic degradation on the sedimentary biomarker record~I: Evidence from Madeira Abyssal Plain turbidites, Geochim. Cosmochim. Ac., 66, 2719–2735, 2002. Hulthe, G., Hulth, S., and Hall, P. O. J.: Effect of oxygen on degradation rate of refractory and labile organic matter in continental margin sediments, Geochim. Cosmochim. Ac., 62, 1319–1328, 1998. Ieno, E. N., Solan, M., Batty, P., and Pierce, G. J.: How biodiversity affects ecosystem functioning: roles of infaunal species richness, identity and density in the marine benthos, Mar. Ecol.-Prog. Ser., 311, 263–271, 2006. Ingall, E. and Jahnke, R.: Influence of water-column anoxia on the elemental fractionation of carbon and phosphorus during sediment diagenesis, Mar. Geol., 139, 219–229, 1997. Jeppesen, E., Sondergaard, M., Jensen, J. P., Havens, K. E., Anneville, O., Carvalho, L., Coveney, M. F., Deneke, R., Dokulil, M. T., Foy, B., Gerdeaux, D., Hampton, S. E., Hilt, S., Kangur, K., Kohler, J., Lammens, E., Lauridsen, T. L., Manca, M., Miracle, M. R., Moss, B., Noges, P., Persson, G., Phillips, G., Portielje, R., Schelske, C. L., Straile, D., Tatrai, I., Willen, E., and Winder, M.: Lake responses to reduced nutrient loading - an analysis of contemporary long-term data from 35 case studies, Freshwat. Biol., 50, 1747–1771, 2005. Jordan, T. E., Cornwell, J. C., Boynton, W. R., and Anderson, J. T.: Changes in phosphorus biogeochemistry along an estuarine salinity gradient: The iron conveyer belt, Limnol. Oceanogr., 53, 172–184, 2008. Jørgensen, B. B.: Mineralization of organic matter in the sea bed – the role of sulphate reduction, Nature, 296, 643–645, 1982. Jørgensen, B. B.: Sulphur cycle of a coastal marine sediment (Limfjorden, Denmark), Limnol. Oceanogr., 22, 814–832, 1977. Jørgensen, B. B.: Bacteria and marine biogeochemistry, edited by: Shulz, H. D. and Zabel, M., Mar. Geochem., 169–206, 2006. Jørgensen, B. B. and Gallardo, V. A.: \textitThioploca spp.: filamentous sulphur bacteria with nitrate vacuoles, FEMS Microbial Ecol., 28, 301–313, 1999. Katsev, S., Chaillou, G., Sundby, B., and Mucci, A.: Effects of progressive oxygen depletion on sediment diagenesis and fluxes: A model for the lower St Lawrence River Estuary, Limnol. Oceanogr., 52, 2555–2568, 2007. Kemp, W. M., Sampou, P., Caffrey, J., Mayer, M., Henriksen, K., and Boynton, W. R.: Ammonium recycling versus denitrification in chesapeake bay sediments, Limnol. Oceanogr., 35, 1545–1563, 1990. Kemp, W. M., Boynton, W. R., Adolf, J. E., Boesch, D. F., Boicourt, W. C., Brush, G., Cornwell, J. C., Fisher, T. R., Glibert, P. M., Hagy, J. D., Harding, L. W., Houde, E. D., Kimmel, D. G., Miller, W. D., Newell, R. I. E., Roman, M. R., Smith, E. M., and Stevenson, J. C.: Eutrophication of Chesapeake Bay: historical trends and ecological interactions, Mar. Ecol.-Prog. Ser., 303, 1–29, 2005. Kemp, W. M., Testa, J., Conley, D., Gilbert, D., and Hagy, J.: Coastal hypoxia responses to remediation, accepted, in process of publication, Biogeos. Disc., 2009. Konovalov, S. K., Luther, G. W., Friederich, G. E., Nuzzio, D. B., Tebo, B. M., Murray, J. W., Oguz, T., Glazer, B., Trouwborst, R. E., Clement, B., Murray, K. J., and Romanov, A. S.: Lateral injection of oxygen with the Bosporus plume – fingers of oxidizing potential in the Black Sea, Limnol. Oceanogr., 48, 2369–2376, 2003 Konovalov, S. K., Luther, G. W., and Yucel, M.: Porewater redox species and processes in the Black Sea sediments, Chem. Geol., 245, 254–274, 2007. Kristensen, E., Ahmed, S. I., and Devol, A. H.: Aerobic and anaerobic decomposition of organic matter in marine sediment: Which is fastest?, Limnol. Oceanogr., 40, 1430–1437, 1995. Kristensen, E., Kristiansen, K. D., and Jensen, M. H.: Temporal behavior of manganese and iron in a sandy coastal sediment exposed to water column anoxia, Estuaries, 26, 690–699, 2003. Kristiansen, K. D., Kristensen, E., and Jensen, M. H.: The influence of water column hypoxia on the behaviour of manganese and iron in sandy coastal marine sediment, Estuar. Coast. Shelf S., 55, 645–654, 2002. Lam, P., Jensen, M. M., Lavik, G., McGinnis, D. F., Muller, B., Schubert, C. J., Amann, R., Thamdrup, B., and Kuypers, M. M. M.: Linking crenarchaeal and bacterial nitrification to anammox in the Black Sea, P. Natl. Acad. Sci. USA, 104, 7104–7109, 2007. Lamont, P. A. and Gage, J. D.: Morphological responses of macrobenthic polychaetes to low oxygen on the Oman continental slope, NW Arabian Sea, Deep-Sea Res. Pt. II, 47, 9–24, 2000. Larson, F. and Sundback, K.: Role of microphytobenthos in recovery of functions in a shallow-water sediment system after hypoxic events, Mar. Ecol.-Prog. Ser., 357, 1–16, 2008. Lavik, G., Stuhrmann, T., Brüchert, V., Van der Plas, A., Mohrholz, V., Lam, P., Mussmann, M., Fuchs, B. M., Amann, R., Lass, U., and Kuypers, M. M. M.: Detoxification of sulphidic African shelf waters by blooming chemolithotrophs, Nature, 457, 581–586, 2009. Lee, C.: Controls on organic carbon preservation – the use of stratified water bodies to compare intrinsic rates of decomposition in oxic and anoxic systems, Geochim. Cosmochim. Ac., 56, 3323–3335, 1992. Levin, L., Blair, N., DeMaster, D., Plaia, G., Fornes, W., Martin, C., and Thomas, C.: Rapid subduction of organic matter by maldanid polychaetes on the North Carolina slope, J. Mar. Res., 55, 595–611, 1997. Levin, L. A., Gage, J. D., Martin, C., and Lamont, P. A.: Macrobenthic community structure within and beneath the oxygen minimum zone, NW Arabian Sea, Deep-Sea Res. Pt. II, 47, 189–226, 2000. Levin, L. A.: Oxygen minimum zone benthos: Adaptation and community response to hypoxia, Ann. Rev. Oceanogr. Mar. Biol., 41, 1–45, 2003. Levin, L. A., Ekau, W., Gooday, A. J., Jorissen, F., Middelburg, J. J., Naqvi, W., Neira, C., Rabalais, N. N., and Zhang, J.: Effects of natural and human-induced hypoxia on coastal benthos, Biogeosciences Discuss., 6, 3563–3654, 2009. Levin, L. A., Whitcraft, C., Mendoza, G. F., Gonzalez, J., and Cowie, G.: Oxygen and organic matter thresholds for benthic faunal activity on the Pakistan margin oxygen minimum zone (700–1100 m), Deep-Sea Res. Pt. II., 56, 449–471, 2009b. Lewis, B. L., Glazer, B. T., Montbriand, P. J., Luther, G. W., Nuzzio, D. B., Deering, T., Ma, S., and Theberge, S.: Short-term and interannual variability of redox-sensitive chemical parameters in hypoxic/anoxic bottom waters of the Chesapeake Bay, Mar. Chem., 105, 296–308, 2007. Luther, G. W., Ma, S. F., Trouwborst, R., Glazer, B., Blickley, M., Scarborough, R. W., and Mensinger, M. G.: The roles of anoxia, H₂S, and storm events in fish kills of dead-end canals of Delaware inland bays, Estuaries, 27, 551–560, 2004. Lyons, T. W., Berner, R. A., and Anderson, R. F.: Evidence for large preindustrial perturbations of the Black Sea chemocline, Nature, 365, 538–540, 1993. Ma, S. F., Whereat, E. B., and Luther, G. W.: Shift of algal community structure in dead end lagoons of the Delaware Inland Bays during seasonal anoxia, Aquat. Microb. Ecol., 44, 279–290, 2006. Marinelli, R. L. and Williams, T. J.: Evidence for density-dependent effects of infauna on sediment biogeochemistry and benthic-pelagic coupling in nearshore systems, Estuar. Coast. Shelf S., 57, 179–192, 2003. Marinelli, R. L. and Woodin, S. A.: Experimental evidence for linkages between infaunal recruitment, disturbance, and sediment surface chemistry, Limnol. Oceanogr., 47, 221–229, 2002. Mayer, L. M.: Surface area control of organic carbon accumulation in continental shelf sediments, Geochim. Cosmochim. Ac., 58, 1271–1284, 1994. McCarthy, M. J., McNeal, K. S., Morse, J. W., and Gardner, W. S.: Bottom-water hypoxia effects on sediment-water interface nitrogen transformations in a seasonally hypoxic, shallow bay (Corpus christi bay, TX, USA), Estuar. Coasts, 31, 521–531, 2008. Mee, D., Friedrich, J., and Gomoiu, M.: Restoring the Black Sea in times of uncertainty, Oceanography, 18, 100–112, 2005. Mermillod-Blondin, F., Francois-Carcaillet, F., and Rosenberg, R.: Biodiversity of benthic invertebrates and organic matter processing in shallow marine sediments: an experimental study, J. Exp. Mar. Biol. Ecol., 315, 187–209, 2005. Meysman, F. J. R., Boudreau, B. P., and Middelburg, J. J.: Relations between local, nonlocal, discrete and continuous models of bioturbation, J. Mar. Res., 61, 391–410, 2003. Meysman, F. J. R., Boudreau, B. P., and Middelburg, J. J.: Modeling reactive transport in sediments subject to bioturbation and compaction, Geochim. Cosmochim. Ac., 69, 3601–3617, 2005. Meysman, F. J. R., Middelburg, J. J., and Heip, C. H. R.: Bioturbation: a fresh look at Darwin's last idea, Trends Ecol. Evol., 21, 688–695, 2006. Meysman, F. J. R., Malyuga, V. S., Boudreau, B. P., and Middelburg, J. J.: A generalized stochastic approach to particle dispersal in soils and sediments, Geochim. Cosmochim. Ac., 72, 3460–3478, 2008. Meysman, F. J. R. and Middelburg, J. J.: Acid-volatile sulphide (AVS) – A comment, Mar. Chem., 97, 206–212, 2005. Middelburg, J. J.: Organic carbon, sulphur, and iron in recent semi-euxinic sediments of Kau Bay, Indonesia, Geochim. Cosmochim. Ac., 55, 815–828, 1991. Middelburg, J. J. and Meysman, F. J. R.: Ocean science – Burial at sea, Science, 316, 1294–1295, 2007. Middelburg, J. J., Calvert, S. E., and Karlin, R.: Organic-rich transitional facies in silled basins – Response to sea-level change, Geology, 19, 679–682, 1991. Middelburg, J. J., Vlug, T., and Van der Nat, F.: Organic matter mineralization in marine systems, Global Planet. Change, 8, 47–58, 1993. Middelburg, J. J., Soetaert, K., Herman, P. M. J., and Heip, C. H. R.: Denitrification in marine sediments: A model study, Global Biogeochem. Cy., 10, 661–673, 1996. Monteiro, P. M. S., van der Plas, A., Mohrholz, V., Mabille, E., Pascall, A., and Joubert, W.: Variability of natural hypoxia and methane in a coastal upwelling system: Oceanic physics or shelf biology?, Geophys. Res. Lett., 33, L16614, doi:10.129/2006GL026234, 2006. Monteiro, P. M. S., van der Plas, A. K., Melice, J. L., and Florenchie, P.: Interannual hypoxia variability in a coastal upwelling system: Ocean-shelf exchange, climate and ecosystem-state implications, Deep-Sea Res. Pt. I, 55, 435–450, 2008. Montserrat, F., Van Colen, C., Degraer, S., Ysebaert, T., and Herman, P. M. J.: Benthic community-mediated sediment dynamics, Mar. Ecol.-Prog. Ser., 372, 43–59, 2008. Moodley, L., Middelburg, J. J., Herman, P. M. J., Soetaert, K., and de Lange, G. J.: Oxygenation and organic-matter preservation in marine sediments: Direct experimental evidence from ancient organic carbon-rich deposits, Geology, 33, 889–892, 2005. Morales, C. E., Hormazabal, S. E., and Blanco, J. L.: Interannual variability in the mesoscale distribution of the depth of the upper boundary of the oxygen minimum layer off northern Chile (18–24S): Implications for the pelagic system and biogeochemical cycling, J. Mar. Res., 57, 909–932, 1999. Morse, J. W. and Eldridge, P. M.: A non-steady state diagenetic model for changes in sediment biogeochemistry in response to seasonally hypoxic/anoxic conditions in the "dead zone" of the Louisiana shelf, Mar. Chem., 106, 239–255, 2007. Mortimer, C. H.: The exchange of dissolved substances between mud and water in lakes, Part~I and II, J. Ecol., 29, 280–329, 1941. Mountford, N. K., Holland, A. F., and Mihursky, J. A.: Identification and Description of Macrobenthic Communities in Calvert Cliffs Region of Chesapeake Bay, Chesapeake Science, 18, 360–369, 1977. Naqvi, S. W. A., Jayakumar, D. A., Narvekar, P. V., Naik, H., Sarma, V. V. S. S., D'Souza, W., Joseph, T., and George, M. D.: Increased marine production of N₂O due to intensifying anoxia on the Indian continental shelf, Nature, 408, 346–349, 2000. Naqvi, S. W. A., Naik, H., Pratihary, A., D'Souza, W., Narvekar, P. V., Jayakumar, D. A., Devol, A. H., Yoshinari, T., and Saino, T.: Coastal versus open-ocean denitrification in the Arabian Sea, Biogeosciences, 3, 621–633, 2006. Naqvi, S. W. A., Bange, H., Farias, L., Monteiro, P. M. S, and Zhang, J.: Coastal hypoxia/anoxia as a source of CH₄ and N₂O, Biogeosci. Discuss., in preparation, 2009. Neira, C., Sellanes, J., Soto, A., Gutierrez, D., and Gallardo, V. A.: Meiofauna and sedimentary organic matter off Central Chile: response to changes caused by the 1997–1998 El Nino, Oceanol. Acta, 24, 313–328, 2001. Nilsson, H. C. and Rosenberg, R.: Succession in marine benthic habitats and fauna in response to oxygen deficiency: analysed by sediment profile-imaging and by grab samples, Mar. Ecol.-Prog. Ser., 197, 139–149, 2000. Norkko, A., Rosenberg, R., Thrush, S. F., and Whitlatch, R. B.: Scale- and intensity-dependent disturbance determines the magnitude of opportunistic response, J. Exp. Mar. Biol. Ecol., 330, 195–207, 2006. Norling, P. and Kautsky, N.: Structural and functional effects of Mytilus edulis on diversity of associated species and ecosystem functioning, Mar. Ecol.-Prog. Ser., 351, 163–175, 2007. Officer, C. B., Biggs, R. B., Taft, J. L., Cronin, L. E., Tyler, M. A., and Boynton, W. R.: Chesapeake Bay Anoxia – Origin, Development, and Significance, Science, 223, 22–27, 1984. Olenin, S.: Benthic zonation of the eastern Gotland Basin, Baltic Sea. Neth., J. Aquat. Ecol., 30, 265–282, 1997. Overmann, J., Cypionka, H., and Pfennig, N.: An extremely low-light adapted phototrophic sulphur bacterium from the Black Sea, Limnol. Oceanogr., 37, 150–155, 1992. Pakhornova, S. V., Hall, P. O. J., Kononets, M. Y., Rozanov, A. G., Tengberg, A., and Vershinin, A. V.: Fluxes of iron and manganese across the sediment-water interface under various redox conditions, Mar. Chem., 107, 319–331, 2007. Passier, H. F., Middelburg, J. J., de Lange, G. J., and Bottcher, M. E.: Pyrite contents, microtextures, and sulphur isotopes in relation to formation of the youngest eastern Mediterranean sapropel, Geology, 25, 519–522, 1997. Pearson, T. H. and Rosenberg, R.: Macrobenthic succession in relation to organic enrichment and pollution of the marine environment, Ann. Rev. Oceanogr. Mar. Biol., 16, 229–311, 1978. Pedersen, T. F. and Calvert, S. E.: Anoxia vs productivity – What controls the formation of organic-carbon-rich sediments and sedimentary rocks, AAPG Bull.-Am. Assoc. Petr. Geol., 74, 454–466, 1990. Percy, D., Li, X. N., Taylor, G. T., Astor, Y., and Scranton, M. I.: Controls on iron, manganese and intermediate oxidation state sulphur compounds in the Cariaco Basin, Mar. Chem., 111, 47–62, 2008. Pihl, L., Baden, S. P., Diaz, R. J. and Schaffner, L. C.: Hypoxia induced structural changes in the diets of bottom-feeding fish and crustacea, Mar. Biol., 112, 349–362, 1992. Quiroga, E., Quinones, R., Palma, M., Sellanes, J., Gallardo, V. A., Gerdes, D., and Rowe, G.: Biomass size-spectra of macrobenthic communities in the oxygen minimum zone off Chile, Estuar. Coast. Shelf S., 62, 217–231, 2005. Rabalais, N. N., Atilla, N., Normandeau, C., and Turner, R. E.: Ecosystem history of Mississippi River-influenced continental shelf revealed through preserved phytoplankton pigments, Mar. Pollut. Bull., 49, 537–547, 2004. Rabalais, N. N., Harper Jr., D. E., and Turner, R. E.: Responses of nekton and demersal and benthic fauna to decreasing oxygen concentrations, in: Coastal and Estuarine Studies: Coastal Hypoxia Consequences for Living Resources and Ecosystems, edited by: Rabalais, N. N. and Turner, R. E., American Geophysical Union, Washington, D. C., 115–128, 2001a. Rabalais, N. N., Smith, L. E., Harper Jr., D. E. and Dubravko, J.: Effects of Seasonal Hypoxia on Continental Shelf Benthos, in: Coastal and Estuarine Studies: Coastal Hypoxia Consequences for Living Resources and Ecosystems, edited by: Rabalais, N. N. and Turner, R. E., American Geophysical Union, Washington, D. C., 211–240, 2001b. Raghoebarsing A. A., Pol, A., van de Pas-Schoonen, K. T., Smolders, A. J. P., Ettwig, K. F., Rijpstra, W. I. C., Schouten, S., Sinninghe Damsté, J. S., Op den Camp, H. J. M., Jetten, M. S. M., and Strous, M.: A microbial consortium couples anaerobic methane oxidation to denitrification, Nature, 440, 918–921, 2006. Reimers, C. E. and Suess, E.: The partitioning of organic-carbon fluxes and sedimentary organic matter decomposition rates in the ocean, Mar. Chem., 13, 141–168, 1983. Reise, K.: Tidal Flat Ecology: An experimental approach to species interactions, Ecological Studies~54, Springer-Verlag, Berlin, 191pp., 1985. Rhoads, D. C. and Boyer, L. F.: The effects of marine benthos on physical properties of sediments: a successional perspective, In: Animal-sediment relations, edited by: McCall, P. L. and Tevesz, M. J. S., Plenum Press, New York, pp.3–52, 1982. Rhoads, D. C. and Morse, J. W.: Evolutionary and ecological significance of oxygen-deficient marine basins, Lethaia, 4, 413–428, 1971. Rhoads D. C.: Organism sediment relations on the muddy sea floor, Ann. Rev. Ocean. Mar. Biol., 12, 263–300, 1974. Ritter, C. and Montagna, P. A.: Seasonal hypoxia and models of benthic response in a Texas bay, Estuaries, 22, 7–20, 1999. Rosenberg, R., Hellman, B., and Johansson, B.: Hypoxic tolerance of marine benthic fauna, Mar. Ecol.-Prog. Ser., 79, 127–131, 1991. Rosenberg, R., Agrenius, S., Hellman, B., Nilsson, H. C., and Norling, K.: Recovery of marine benthic habitats and fauna in a Swedish fjord following improved oxygen conditions, Mar. Ecol.-Prog. Ser., 234, 43–53, 2002. Rossi, F., Gribsholt, B., Middelburg, J. J., and Heip, C.: Context-dependent effects of suspension feeding on intertidal ecosystem functioning, Mar. Ecol.-Prog. Ser., 354, 47–57, 2008. Rossi, F., Vos, M., Middelburg, J. J.: Species identity, diversity and microbial carbon flow in reassembling macrobenthic communities, Oikos, 118, 503–512, 2009. Rozan, T. F., Taillefert, M., Trouwborst, R. E., Glazer, B. T., Ma, S. F., Herszage, J., Valdes, L. M., Price, K. S., and Luther, G. W.: Iron-sulphur-phosphorus cycling in the sediments of a shallow coastal bay: Implications for sediment nutrient release and benthic macroalgal blooms, Limnol. Oceanogr., 47, 1346–1354, 2002. Rowe, G. T., Kaegi, M. E. C., Morse, J. W., Boland, G. S., and Briones, E. G. E.: Sediment community metabolism associated with continental shelf hypoxia, Northern Gulf of Mexico, Estuaries, 25, 1097–1106, 2002. Rowe, G. T., Morse, J., Nunnally, C., and Boland, G. S.: Sediment community oxygen consumption in the deep Gulf of Mexico, Deep-Sea Res. Pt. II, 55, 2686–2691, 2008. Savrda, C. E. and Bottjer, D. J.: The exaerobic zone, a new oxygen deficient marine biofacies, Nature, 327, 54–56, 1987. Savrda, C. E. and Bottjer, D. J.: Oxygen-related biofacies in marine strata: an overview and update, in: Modern and ancient continental shelf anoxia, edited by: Tyson, R. V. and Pearson, T. H., Geol. Soc. Spec. Publ., 58, 201–219, 1991 Savrda, C. E., Bottjer, D. J., and Gorsline, D. S.: Development of a comprehensive oxygen-deficient marine biofacies model; evidence from Santa Monica, San Pedro, and Santa Barbara basins, California continental borderland, AAPG Bull., 58, 1179–1192, 1984. Schaffner L. C., Jonsson P., Diaz R. J., Rosenberg R., and Gapcynski P.: Benthic communities and bioturbation history of estuarine and coastal systems: effects of hypoxia and anoxia, Sci. Total Environ. (supplement), 1001–1017, 1992. Schulz, H. N. and Jorgensen, B. B.: Big bacteria, Annu. Rev. Microbiol., 55, 105–137, 2001. Schulz, H. N. and Schulz, H. D.: Large sulphur bacteria and the formation of phosphorite, Science, 307, 416–418, 2005. Sellanes, J. and Neira, C.: ENSO as a natural experiment to understand environmental control of meiofaunal community structure, Mar. Ecol.-Evol. Persp., 27, 31–43, 2006. Sellanes, J., Neira, C., and Quiroga, E.: Composition, structure and energy flux of the meiobenthos off central Chile, Rev. Chil. Hist. Nat., 76, 401–415, 2003. Sellanes, J., Quiroga, E., Neira, C., and Gutierrez, D.: Changes of macrobenthos composition under different ENSO cycle conditions on the continental shelf off central Chile, Cont. Shelf Res., 27, 1002–1016, 2007. Severmann, S., Lyons, T. W., Anbar, A., McManus, J., and Gordon, G.: Modern iron isotope perspective on the benthic iron shuttle and the redox evolution of ancient oceans, Geology, 36, 487–490, 2008. Shaffer, G.: Phosphate Pumps and Shuttles in the Black-Sea, Nature, 321, 515–517, 1986. Sholkovitz, E. R. and Gieskes J. M.: A physical chemical study of the flushing of the Santa Barbara Basin, Limnol. Oceanogr., 16, 479–489, 1971. Slomp, C. P., Epping, E. H. G., Helder, W., and Van Raaphorst, W.: A key role for iron-bound phosphorus in authigenic apatite formation in North Atlantic continental platform sediments, J. Mar. Res., 54, 1179–1205, 1996. Slomp, C. P. and Van Cappellen, P.: The global marine phosphorus cycle: sensitivity to oceanic circulation, Biogeosciences, 4, 155–171, 2007. Soetaert, K. and Middelburg, J. J.: Modeling eutrophication and oligotrophication of shallow-water marine systems: the importance of sediments under stratified and well mixed conditions, Hydrobiologia, 629, 239–254, 2009. Soetaert, K., Herman, P. M. J., and Middelburg, J. J.: A model of early diagenetic processes from the shelf to abyssal depths, Geochim. Cosmochim. Ac., 60, 1019–1040, 1996. Soetaert, K., Middelburg, J. J., Herman, P. M. J., and Buis, K.: On the coupling of benthic and pelagic biogeochemical models, Earth-Sci. Rev., 51, 173–201, 2000. Strous, M. and Jetten, M. S. M.: Anaerobic oxidation of methane and ammonium, Annu. Rev. Microbiol., 58, 99–117, 2004. Suess, E.: Mineral phases formed in anoxic sediments by microbial decomposition of organic matter, Geochim. Cosmochim. Ac., 43, 339–352, 1979. Sundby, B., Gobeil, C., Silverberg, N., and Mucci, A.: The phosphorus cycle in coastal marine sediments, Limnol. Oceanogr., 37, 1129–1145, 1992. Sundby, B., Anderson, L. G., Hall, P. O. J., Iverfeldt, A., Vanderloeff, M. M. R., and Westerlund, S. F. G.: The effect of oxygen on release and uptake of cobalt, manganese, iron and phosphate at the sediment-water interface, Geochim. Cosmochim. Ac., 50, 1281–1288, 1986. Sundby, B. and Silverberg, N.: Manganese fluxes in the benthic boundary layer, Limnol. Oceanogr., 30, 372–381, 1985. Taylor, G. T., Labichella, M., Ho, T. Y., Scranton, M. I., Thunell, R. C., Muller-Karger, F., and Varela, R.: Chemoautotrophy in the redox transition zone of the Cariaco Basin: A significant midwater source of organic carbon production, Limnol. Oceanogr., 46, 148–163, 2001. Thamdrup, B.: Bacterial manganese and iron reduction in aquatic sediments, Adv. Microb. Ecol., 16, 41–84, 2000. Thamdrup, B., Canfield D. E., Ferdelman T. G., Glud R. N., and Gundersen J. K.: A biogeochemical survey of the anoxic basin Golfo Dulce, Costa Rica, Rev. Biol. Trop., 44 Suppl., 3, 19–33, 1996. Thamdrup, B., Fossing, H., and Jorgensen, B. B.: Manganese, iron, and sulphur cycling in a coastal marine sediment, Aarhus Bay, Denmark, Geochim. Cosmochim. Ac., 58, 5115–5129, 1994. Thomson, J., Mercone, D., de Lange, G. J., and van Santvoort, P. J. M.: Review of recent advances in the interpretation of eastern Mediterranean sapropel S$_1$ from geochemical evidence, Mar. Geol., 153, 77–89, 1999. Toth, D. J. and Lerman, A.: Organic matter reactivity and sedimentation rates in ocean, Am. J. Sci., 277, 465–485, 1977. Turner, R. E., Rabalais, N. N., and Justic, D.: Gulf of Mexico hypoxia: Alternate states and a legacy, Environ. Sci. Technol., 42, 2323–2327, 2008. Tyson, R. V.: Sedimentary Organic matter, Chapman and Hall, 1995. Vaquer-Sunyer, R. and Duarte, C. M.: Thresholds of hypoxia for marine biodiversity, P. Natl. Acad. Sci. USA, 105, 15452–15457, 2008. Van Colen, C., Montserrat, F., Vincx, M., Herman, P. M. J., Ysebaert, T., and Degraer, S.: Macrobenthic recovery from hypoxia in an estuarine tidal mudflat, Mar. Ecol.-Prog. Ser., 372, 31–42, 2008. Vandewiele, S., Cowie, G., Soetaert, K., and Middelburg, J. J.: Amino acid biogeochemistry and organic matter degradation state accross the Pakistan Margin Oxygen minimum zone, Deep-Sea Res. Pt. II, 56, 376–392, 2009. van Nugteren, P., Herman, P. M. J., Moodley, L., Middelburg, J. J., Vos, M., and Heip C. H. R.: Spatial distribution of detrital resources determines the outcome of competition between bacteria and a facultative detritivorous worm, Limnol. Oceanogr., 54, 1413–1419, 2009. Voss, M., Nausch, G., and Montoya, J. P.: Nitrogen stable isotope dynamics in the central Baltic Sea: influence of deep-water renewal on the N-cycle changes, Mar. Ecol.-Prog. Ser., 158, 11–21, 1997. Waldbusser, G. G. and Marinelli, R. L.: Macrofaunal modification of porewater advection: role of species function, species interaction, and kinetics, Mar. Ecol.-Prog. Ser., 311, 217–231, 2006. Waldbusser, G. G., Marinelli, R. L., Whitlatch, R. B., and Visscher, P. T.: The effects of infaunal biodiversity on biogeochemistry of coastal marine sediments, Limnol. Oceanogr., 49, 1482–1492, 2004. Wallmann, K.: Feedbacks between oceanic redox states and marine productivity: A model perspective focused on benthic phosphorus cycling, Global Biogeochem. Cy., 17(3), 1084, doi:10.1029/2002GB001968.doi, 2003. Werne, J. P., Lyons, T. W., Hollander, D. J., Schouten, S., Hopmans, E. C., and Damsté, J. S. S.: Investigating pathways of diagenetic organic matter sulfurization using compound-specific sulfur isotope analysis. Geochim. Cosmochim. Ac., 72, 3489–3502, 2008. Westrich, J. T. and Berner, R. A.: The role of sedimentary organic matter in bacterial sulphate reduction – the G model tested, Limnol. Oceanogr., 29, 236–249, 1984. Wheatcroft, R. A.: Characteristic trace-fossil associations in oxygen-poor sedimentary environments – Comment, Geology, 17, p 674, 1989. Widdows, J., Blauw, A., Heip, C. H. R., Herman, P. M. J., Lucas, C. H., Middelburg, J. J., Schmidt, S., Brinsley, M. D., Twisk, F., and Verbeek, H.: Role of physical and biological processes in sediment dynamics (sedimentation, erosion and mixing) of a tidal flat in Westerschelde estuary, S.W. Netherlands, Mar. Ecol.-Prog. Ser., 274, 41–56, 2004. Wijsman, J. W. M., Middelburg, J. J., and Heip, C. H. R.: Reactive iron in Black Sea Sediments: implications for iron cycling, Mar. Geol., 172, 167–180, 2001. Wilson, T. R. S., Thomson, J., Colley, S., Hydes, D. J., Higgs, N. C., and Sorensen, J.: Early Organic Diagenesis – the Significance of Progressive Subsurface Oxidation Fronts in Pelagic Sediments, Geochim. Cosmochim. Ac., 49, 811–822, 1985. Woulds, C., Cowie, G. L., Levin, L. A., Andersson, J. H., Middelburg, J. J., Vandewiele, S., Lamont, P. A., Larkin, K. E., Gooday, A. J., Schumacher, S., Whitcraft, C., Jeffreys, R. M., and Schwartz, M.: Oxygen as a control on seafloor biological communities and their roles in sedimentary carbon cycling, Limnol. Oceanogr., 52, 1698–1709, 2007. Woulds, C., Andersson, J. H., Cowie, G. L., Middelburg, J. J., and Levin, L. A.: $^13$C tracer studies on the short-term fate of organic carbon in marine sediments: comparing the Pakistan margin to other regions, Deep-Sea Res. Pt. II, 56, 393–402, 2009. Wüchter, C., Abbas, B., Coolen, M. J. L., Herfort, L., van Bleijswijk, J., Timmers, P., Strous, M., Teira, E., Herndl, G. J., Middelburg, J. J., Schouten, S., and Damsté, J. S. S.: Archaeal nitrification in the ocean, P. Natl. Acad. Sci. USA, 103, 12317–12322, 2006. Yakushev, E. V., Pollehne, F., Jost, G., Kuznetso, I., Schneider, B., and Urnlauf, L.: Analysis of the water column oxic/anoxic interface in the Black and Baltic seas with a numerical model, Mar. Chem., 107, 388–410, 2007. Zopfi, J., Ferdelman, T. G., Jorgensen, B. B., Teske, A., and Thamdrup, B.: Influence of water column dynamics on sulphide oxidation and other major biogeochemical processes in the chemocline of Mariager Fjord (Denmark), Mar. Chem., 74, 29–51, 2001.