Abstract

Based on the study of separate areas of Lake Baikal (depth from 14 to 250 m), influence of the grain size composition of bottom sediments on the distribution of methane and sulfide sulfur is examined. Concentrations of the components varied, respectively, from <0.01 to 1.81 µg/g d.s. (average 0.21 µg/g d.s.) and from 0.002 to 0.384 mg/g d.s. (average 0.027 mg/g d.s.). Comparison of the distribution of methane and sulfide sulfur concentrations testifies to active sulfate reduction at the same stations, where methane concentrations are highest, precisely in the northern area of the lake marked by the inflow of the Verkhnyaya Angara and Kichera rivers, as well as at some stations of the profile deployed along the estuarine zone of the Selenga River and stations located in the sublacustrine wastewater discharge zone of the town of Baikal’sk and the Baikal’sk Pulp and Paper Mill (BPPM), which was closed in 2013. Depending on the study area and sampling point depth, the share of the sand fraction (0.05–2.0 mm) in bottom sediments varies from 23 to 99% (average 57%); the silt fraction (0.05–0.005 mm), from 1 to 73% (average 39%), and the pelite fraction (<0.005 mm), from 0.0 to 8.7% (average 4%). Increase of the concentration of reduced gases in sediments correlates tightly with increase of the share of the fine-grained (silt and pelite) fractions. It is concluded that high or low concentrations of methane and sulfide sulfur at the studied upper intervals of sediments in Lake Baikal are caused not only by differences in the thickness of sediments subjected to the anthropogenic impact, but also by variations in depositional conditions that govern the grain size composition and, consequently, the content of organic matter and intensity of methane genesis and sulfate reduction.

中文翻译：

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贝加尔湖底部沉积物粒度组成对甲烷和硫化物硫分布的影响

摘要

在对贝加尔湖不同区域（深度从14至250 m）进行研究的基础上，研究了底部沉积物的粒度组成对甲烷和硫化物硫分布的影响。组分的浓度分别从<0.01至1.81 µg / g ds（平均0.21 µg / g ds）和0.002至0.384 mg / g ds（平均0.027 mg / g ds）变化。甲烷和硫化物硫浓度分布的比较证明，在同一站，甲烷浓度最高，正是在湖的北部地区，以Verkhnyaya Angara河和Kichera河的流入为标志，主动硫酸盐的还原，以及沿塞伦加河河口区展开的剖面的某些站点以及位于贝加尔斯克市和贝加尔斯克纸浆造纸厂（BPPM）的湖底废水排放区的站点，这些站点已关闭在2013年。根据研究区域和采样点深度，底部沉积物中沙粒份额（0.05–2.0 mm）的比例从23％到99％不等（平均57％）；泥沙分数（0.05-0.005毫米），从1到73％（平均39％），以及白云母分数（<0.005毫米），从0.0到8.7％（平均4％）。沉积物中还原性气体浓度的增加与细粒（粉砂和贝利特）级分所占份额的增加紧密相关。。