Chemical and isotopic composition of interstitial waters from the Kara Sea and Yenisey estuary

Processes of early sediment diagenesis, including chemical composition of interstitial waters, content of different sulfur compounds, and rates of sulfate reduction were investigated. Along a profile from the Yenisey River to the Kara Sea, sulfate reduction intensities were high (up to 1.5 µg S/kg/day) in the delta region and in its northern part. Intensities were comparable to those found in shallow-water sediments of the North Sea. In estuarine sediments, where different transformations were possible, lower rates of bacterial sulfate reduction were observed (0.03 to 0.06 µg S/kg/day). Annual production of reduced sulfur in sediments was 24 million tons, and only 0.5 million tons (2%) were deposited. Annual consumption of organic carbon during process of sulfate reduction in the Yenisey delta region was 17.6 million tons.

本研究针对早期沉积物成岩作用（early sediment diagenesis）的相关过程展开系统调研，涵盖间隙水（interstitial waters）的化学组成、不同硫化合物（sulfur compounds）的含量以及硫酸盐还原作用（sulfate reduction）速率等维度。沿叶尼塞河（Yenisey River）至喀拉海（Kara Sea）的剖面采样分析显示，三角洲区域及其北部海域的硫酸盐还原作用强度较高，最高可达1.5微克硫/千克·天。该强度与北海（North Sea）浅水区沉积物中的硫酸盐还原作用强度相当。在可发生多种转化过程的河口沉积物（estuarine sediments）中，观测到的细菌硫酸盐还原作用（bacterial sulfate reduction）速率较低，介于0.03至0.06微克硫/千克·天之间。沉积物中还原态硫（reduced sulfur）的年生成总量达2400万吨，其中仅有50万吨（占比2%）得以沉积保存。叶尼塞河三角洲区域内，硫酸盐还原作用过程中消耗的有机碳（organic carbon）年总量为1760万吨。