Benthic weathering of calcite and dunite in benthocosm experiments between Sept. 2022 and Sept. 2023@en

Enhanced benthic weathering has been proposed to serve as a efficient negative emission strategy. The precise weathering behaviour of calcite and dunite was investigated in long-term experiments in benthocosms. These experiments were conducted between Sept. 2022 and Sept. 2023 ashore at the Kiel Fjord. The latter are large plastic containers (~0.8 m²) that are partly filled with sediments, with constant flow-through of Baltic Sea bottom water. The sediments, obtained from Boknis Eck in the Eckernförde Bay in March 2022, were amended with calcite and dunite in triplicate (22 mol/m² equivalent) . Three additional benthocosms were left unamended to serve as controls. The used materials were obtained from Sibelco (dunite) and from the german Lime Stone Association (calcite). These experiments elucidate the actual weathering behavior of calcite and dunite under conditions as close to the natural system as possible. Samples were obtained using benthic chambers (chamber volume of 400 ml) that were placed on the sediment for three hours. Samples were taken at the beginning (_in) and at the end of the deployment (_out).增强型底栖风化（benthic weathering）已被提出作为一种高效的负排放策略。研究人员针对方解石（calcite）与纯橄榄岩（dunite）的精确风化行为，在底栖模拟生态系统（benthocosms）中开展了长期实验。实验于2022年9月至2023年9月间在基尔峡湾（Kiel Fjord）陆上实验场地开展。底栖模拟生态系统为占地面积约0.8平方米的大型塑料容器，内部部分填充沉积物，并持续通入波罗的海（Baltic Sea）底层海水。沉积物于2022年3月采自埃克恩弗尔德湾（Eckernförde Bay）的博克尼斯埃克站（Boknis Eck），以一式三份的平行设置添加了当量为22 mol/m²的方解石与纯橄榄岩；另设置3个未添加任何处理的底栖模拟生态系统作为对照组。所用实验材料分别购自西比科公司（Sibelco，纯橄榄岩）与德国石灰石协会（German Lime Stone Association，方解石）。本系列实验阐明了方解石与纯橄榄岩在尽可能贴近自然系统的条件下的实际风化行为。样品采集采用底栖采样舱（benthic chambers，单舱容积400毫升），将其放置于沉积物表面布设3小时，分别于布设开始时（标记为_in）与布设结束时（标记为_out）采集样品。