Ex situ sulphate reduction rates of sediment at the rim of a vesicomyd clam colony in the Japan Deep Sea Trench (dive 957)

Sediment samples were collected from the rim of a large vesicomyid clam colony in the Japan Deep Sea Trench. Immediately after sample recovery onboard, the sediment core was sub-sampled for ex situ rate measurements. Sulfate reduction were measured ex situ by the whole core injection method with three replicates. We incubated the samples at in situ temperature (1.5°C) for 48 hours with carrier-free 35SO4 (dissolved in water, 50 kBq). Sediment was fixed 20 ml ZnAc solution (20%, w/v) for AOM or SR. Turnover rates were measured as previously described (Kallmeyer et al., 2004).

本研究的沉积物样品采集自日本海沟（Japan Deep Sea Trench）内一处大型vesicomyid蛤（vesicomyid clam）群落的边缘区域。样品在甲板完成回收后即刻，便对沉积物岩芯进行分样以开展异位（ex situ）速率测定。采用全岩芯注入法开展硫酸盐还原（sulfate reduction）的异位测定，设置3组平行样。我们将样品置于原位温度（1.5℃）下孵育48小时，添加溶于水的无载体35SO4（carrier-free 35SO4），活度为50 kBq。沉积物采用20 mL质量体积比为20%的乙酸锌（ZnAc）溶液进行固定，以用于厌氧甲烷氧化（anaerobic oxidation of methane, AOM）或硫酸盐还原相关实验。周转速率的测定方法参照已发表文献（Kallmeyer等，2004）。