Ex situ sulphate reduction and methane oxidation rates of sediment at the rim of a vesicomyd clam colony in the Japan Deep Sea Trench (dive 956)@en

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 and anaerobic oxidation of methane were measured ex situ by the whole core injection method with three replicate measurements for each method. We incubated the samples at in situ temperature (1.5°C) for 48 hours with either 14C-methane (dissolved in water, 2.5 kBq) or carrier-free 35S-sulfate (dissolved in water, 50 kBq). Sediment was fixed in 25 ml sodium hydroxide (NaOH) solution (2.5%, w/v) or 20 ml ZnAc solution (20%, w/v) for AOM or SR, respectively. Turnover rates were measured as previously described (Kallmeyer et al., 2004; Treude et al., 2003).本研究沉积物样品采集自日本海沟（Japan Deep Sea Trench）内一处大型囊鳃类蛤（vesicomyid clam）群落的边缘地带。样品被回收至船载实验室后，即刻对沉积物岩芯进行分样，以开展非原位（ex situ）速率测定。采用全岩芯注入法对硫酸盐还原（sulfate reduction, SR）与甲烷厌氧氧化（anaerobic oxidation of methane, AOM）进行非原位测定，每种方法均设置三次重复测量。将样品置于原位温度（1.5℃）下培养48小时，培养体系分别添加溶于水的¹⁴C-甲烷（2.5 kBq）或无载体³⁵S-硫酸盐（50 kBq）。分别使用25 mL 2.5%（质量体积比，w/v）氢氧化钠（NaOH）溶液与20 mL 20%（w/v）乙酸锌（ZnAc）溶液固定样品，以分别用于AOM与SR测定。周转速率的测定参照已发表方法（Kallmeyer等，2004；Treude等，2003）。