Sulfate reduction and anaerobic methane oxidation in Black Sea sediments

摘要: Beyond the shelf break at ca. 150 mwater depth, sulfate reduction is only important process of organic matter oxidation in Black Sea sediments from surface down to sulfate}methane transition 2} 4m depth. Sulfate rates were measured experimentally with SO , and compared results two di!usion-reaction models. The showed that, even these non-bioirrigated without sul"de reoxidation, modeling strongly underestimated high near sediment surface. A hybrid approach, which upper layers force a model that includes also deeper layers, probably provides most realistic estimate rates. Areal 0.65}1.43 mmol m d, highest just below chemocline. Anaerobic methane accounted for 7}11% total slope deep-sea sediments. Although this methane-driven shaped entire gradient, it was equivalent uppermost 1.5 cm sediment. Methane complete, yet very sluggish turnover times within zone 20 yr or more. 2001 Elsevier Science Ltd. All rights reserved.