Alkaline mineral addition to anoxic to hypoxic Baltic Sea sediments as a potentially efficient CO2-removal technique

IF 4.3 3区材料科学 Q1 ENGINEERING, ELECTRICAL & ELECTRONIC

ACS Applied Electronic Materials Pub Date : 2024-02-02 DOI:10.3389/fclim.2024.1338556

Michael Fuhr, Klaus Wallmann, Andrew W. Dale, H. T. Kalapurakkal, Mark Schmidt, S. Sommer, C. Deusner, Timo Spiegel, Jannes Kowalski, S. Geilert

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Abstract

Recent studies have begun to explore the potential of enhanced benthic weathering (EBW) in the Baltic Sea as a measure for climate change mitigation. To augment the understanding of EBW under seasonally changing conditions, this study aims to investigate weathering processes under anoxia to hypoxia in corrosive bottom waters, which reflect late summer conditions in the Baltic Sea. Dunite and calcite were added to sediment cores retrieved from Eckernförde Bay (Western Baltic Sea) with a constant flow-through of deoxygenated, CO2-enriched Baltic Sea bottom water. The addition of both materials increased benthic alkalinity release by 2.94 μmol cm−2 d−1 (calcite) and 1.12 μmol cm−2 d−1 (dunite), compared to the unamended control experiment. These excess fluxes are significantly higher than those obtained under winter conditions. The comparison with bottom water oxygen concentrations emphasizes that highest fluxes of alkalinity were associated with anoxic phases of the experiment. An increase in Ca and Si fluxes showed that the enhanced alkalinity fluxes could be attributed to calcite and dunite weathering. First order rate constants calculated based on these data were close to rates published in previous studies conducted under different conditions. This highlights the suitability of these proxies for mineral dissolution and justifies the use of these rate constants in modeling studies investigating EBW in the Baltic Sea and areas with similar chemical conditions. Generally stable pH profiles over the course of the experiment, together with the fact that the added minerals remained on the sediment surface, suggest that corrosive bottom waters were the main driving factor for the dissolution of the added minerals. These factors have important implications for the choice of mineral and timing for EBW as a possible marine carbon dioxide removal method in seasonally hypoxic to anoxic regions of the Baltic Sea.

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在缺氧至缺氧的波罗的海沉积物中添加碱性矿物，作为一种潜在的高效二氧化碳去除技术

最近的研究已开始探索波罗的海海底风化增强（EBW）作为减缓气候变化措施的潜力。为了加深对季节性变化条件下 EBW 的了解，本研究旨在调查腐蚀性底层水缺氧至缺氧条件下的风化过程，这反映了波罗的海夏末的状况。在埃肯富尔德湾（波罗的海西部）捞取的沉积物岩芯中添加了 Dunite 和方解石，并不断流过脱氧、富含 CO2 的波罗的海底层水。与未经改良的对照实验相比，添加这两种材料可使底栖生物碱度释放量分别增加 2.94 μmol cm-2 d-1 （方解石）和 1.12 μmol cm-2 d-1 （白云石）。这些过量通量明显高于冬季条件下获得的通量。与底层水氧浓度的比较表明，碱度通量最高的阶段与实验的缺氧阶段有关。钙和硅通量的增加表明，碱度通量的增加可归因于方解石和白云石的风化。根据这些数据计算出的一阶速率常数与以前在不同条件下进行的研究中公布的速率相近。这突出表明了这些矿物质溶解代用指标的适用性，并证明了在波罗的海和具有类似化学条件地区的 EBW 模拟研究中使用这些速率常数是合理的。在实验过程中，pH 值曲线基本稳定，而且添加的矿物质仍留在沉积物表面，这表明腐蚀性底层水是添加矿物质溶解的主要驱动因素。这些因素对于在波罗的海季节性缺氧至缺氧地区选择 EBW 作为一种可能的海洋二氧化碳去除方法的矿物质和时间具有重要意义。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

ACS Applied Electronic Materials Multiple-

CiteScore

7.20

自引率

4.30%

发文量

567

期刊介绍： ACS Applied Electronic Materials is an interdisciplinary journal publishing original research covering all aspects of electronic materials. The journal is devoted to reports of new and original experimental and theoretical research of an applied nature that integrate knowledge in the areas of materials science, engineering, optics, physics, and chemistry into important applications of electronic materials. Sample research topics that span the journal's scope are inorganic, organic, ionic and polymeric materials with properties that include conducting, semiconducting, superconducting, insulating, dielectric, magnetic, optoelectronic, piezoelectric, ferroelectric and thermoelectric. Indexed/Abstracted： Web of Science SCIE Scopus CAS INSPEC Portico