Defining a biogeochemical baseline for sediments at Carbon Capture and Storage (CCS) sites: An example from the North Sea (Goldeneye)
Defining a biogeochemical baseline for sediments at Carbon Capture and Storage (CCS) sites: An example from the North Sea (Goldeneye)
复制标题
DOI：
10.1016/j.ijggc.2021.103265
复制
发表时间：
2021-03
影响因子：
3.9
通讯作者：
A. Dale;S. Sommer;A. Lichtschlag;D. Koopmans;M. Haeckel;E. Kossel;C. Deusner;P. Linke;J. Scholten;K. Wallmann;M. R. Erk;J. Gros;F. Scholz;M. Schmidt
中科院分区：
文献类型：
--
作者：
A. Dale;S. Sommer;A. Lichtschlag;D. Koopmans;M. Haeckel;E. Kossel;C. Deusner;P. Linke;J. Scholten;K. Wallmann;M. R. Erk;J. Gros;F. Scholz;M. Schmidt
将二氧化碳(CO2)注入海底水库作为一项减少人为二氧化碳排放到大气中的战略正在获得支持。然而，来自这些水库的外部供应的二氧化碳的潜在泄漏、迁移和溶解是一个令人担忧的原因。2019年，在一个潜在的碳捕获和储存地点(金眼)，在一个受控的地下二氧化碳释放实验期间，研究了二氧化碳泄漏对北海沉积物和上覆水域生物地球化学的潜在影响。这项研究描述了沉积物的自然(未受干扰的)生物地球化学。有机碳含量较低(∼为0.6%)的泥质砂岩-砂质泥质砂岩。报道了沉积物孔隙水中溶解无机碳(DIC)和总碱度(TA)的分布，以及沉积物与上覆水之间溶解营养物质和氧气的原位通量。利用底栖箱法和涡动协方差法测得进入底泥的氧通量分别为6.18±0.5 8和5.73±2.0 3mmolm−2d-1。讨论了可用于检测CCS现场水库渗漏引起的沉积物中CO2富集度的诊断指标。其中包括沉积物孔隙水中TA和铵与硫酸盐的比率、底栖通量和氯离子归一化阳离子分布。这些指标目前表明，金眼的有机碳的氧化态为零以下，主要通过硫酸盐还原进行降解。碳酸盐降水显然可以忽略不计，而镁离子和钾离子的减少则表明岩性沉积物在逆风化过程中发生了持续的蚀变。
Injection of carbon dioxide (CO2) into subseafloor reservoirs is gaining traction as a strategy for mitigating anthropogenic CO2emissions to the atmosphere. Yet, potential leakage, migration and dissolution of externally-supplied CO2from such reservoirs are a cause for concern. The potential impact of CO2leakage on the biogeochemistry of sediments and overlying waters in the North Sea was studied during a controlled subsurface CO2release experiment in 2019 at a potential carbon capture and storage site (Goldeneye). This study describes the natural (unperturbed) biogeochemistry of sediments. They are classified as muddy sand to sandy mud with low organic carbon content (∼0.6 %). Distributions of dissolved inorganic carbon (DIC) and total alkalinity (TA) in sediment porewaters are reported in addition to in situ benthic fluxes of dissolved nutrients and oxygen between the sediments and the overlying water. Oxygen fluxes into the sediment, measured using benthic chambers and eddy covariance, were 6.18 ± 0.58 and 5.73 ± 2.03 mmol m−2d-1, respectively. Diagnostic indicators are discussed that could be used to detect CO2enrichment of sediments due to reservoir leakage at CCS sites. These include the ratio TA and ammonium to sulfate in sediment porewaters, benthic fluxes and chloride-normalized cation distributions. These indicators currently suggest that the organic carbon at Goldeneye has an oxidation state below zero and is mainly degraded via sulfate reduction. Carbonate precipitation is apparently negligible, whereas decreases in Mg2+and K+point toward ongoing alteration of lithogenic sediments by reverse weathering processes.