DISCOL experiment revisited: Assessing the temporal scale of deep-sea mining impacts on sediment biogeochemistry
DISCOL experiment revisited: Assessing the temporal scale of deep-sea mining impacts on sediment biogeochemistry
复制标题
重温 DISCOL 实验：评估深海采矿对沉积物生物地球化学影响的时间尺度
DOI：
--
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
F. Janssen
中科院分区：
文献类型：
--
作者：
L. Haffert;M. Haeckel;H. D. de Stigter;F. Janssen
抽象的。深海多金属结核采矿预计会对环境产生严重影响，因为除了结核之外，海底动物以及上部活性沉积层也会在采矿作业中被移走，并被悬浮沉积物羽流的重新定居物质覆盖。本研究的目的是提供一个整体评估的生物地球化学恢复扰动事件后，应用预测模拟的基础上更新的成岩背景模型和验证新的（微）生物数据。结果发现，恢复强烈地依赖于影响类型，完全去除的反应性表层沉积物减少了海底营养通量几个世纪以来，而地球化学过程后，再悬浮和混合的表层沉积物是接近预影响状态一年后的干扰。此外，在DISCOL地区的地球化学影响将在一定程度上减轻粘土结合的Fe（II）反应层，阻碍向下扩散的氧气，从而稳定的氧化还原分带的沉积物在短暂的影响后恢复。跨学科（地球化学、数值和生物学）方法突出了底栖生态系统功能的密切联系性质，例如通过生物扰动、微生物生物量和养分通量，这对系统恢复也非常重要。
Abstract. Deep-sea mining for polymetallic nodules is expected to have severe environmental impacts because in addition to the nodules, benthic fauna as well as the upper reactive sediment layer is removed through the mining operation, and blanketed by resettling material from the suspended sediment plume. This study aims to provide a holistic assessment of the biogeochemical recovery after a disturbance event by applying prognostic simulations based on an updated diagenetic background model and validated with novel (micro)-biological data. It was found that the recovery strongly depends on the impact type; complete removal of the reactive surface sediment reduces seafloor nutrient fluxes over centuries, while geochemical processes after resuspension and mixing of the surface sediment are near pre-impact state one year after the disturbance. Furthermore, the geochemical impact in the DISCOL area would be mitigated to some degree by a clay-bound Fe(II)-reaction layer, impeding the downward diffusion of oxygen, thus stabilizing the redox zonation of the sediment during transient post-impact recovery. The interdisciplinary (geochemical, numerical and biological) approach highlights the closely linked nature of benthic ecosystem functions, e.g. through bioturbation, microbial biomass and nutrient fluxes, which is also of great importance for the system recovery.