Measurement and modelling of deep sea sediment plumes and implications for deep sea mining.
Measurement and modelling of deep sea sediment plumes and implications for deep sea mining.
复制标题
深海沉积物羽流的测量和建模及其对深海采矿的影响。
DOI：
10.1038/s41598-020-61837-y
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发表时间：
2020
影响因子：
4.6
通讯作者：
Spearman J
中科院分区：
文献类型：
--
作者：
Spearman J
深海采矿涉及从海底开采多金属结核、富钴结壳和硫化物矿床。对这些资源的开发将产生不利的生态影响，因为直接去除底物，并可能形成沉积物羽流，从而可能导致在敏感物种上沉积细小的沉积物，或将沉积物、化学品和营养物质夹带到上覆水域。因此，确定深海沉积物羽流的行为对于设计在生态上可接受的采矿作业很重要。在这里，我们介绍了在加那利群岛西南300海里的热带海山上进行的新型深海羽流实验的结果。这些羽流实验伴随着水文和海洋实地调查，并得到详细的数值模拟和实验室内进行的现场高分辨率视频沉降速度测量的支持。羽流实验包括控制海底沉积物羽流的形成，并在一个特别设计的着陆器上测量羽流沉积物浓度，着陆器放置在离羽状物起点一定距离的地方。这些实验被用作验证数值扩散模型的基础，该模型随后被用来预测全面采矿产生的羽流的扩散。结果表明，由于絮凝、背景浑浊和内潮的影响，采矿作业产生的海底沉积物羽流的扩散程度显著降低。在评估海底沉积物羽流的影响和程度时，必须考虑到这些因素。
Deep sea mining concerns the extraction of poly-metallic nodules, cobalt-rich crusts and sulphide deposits from the ocean floor. The exploitation of these resources will result in adverse ecological effects arising from the direct removal of the substrate and, potentially, from the formation of sediment plumes that could result in deposition of fine sediment on sensitive species or entrainment of sediment, chemicals and nutrients into over-lying waters. Hence, identifying the behaviour of deep-sea sediment plumes is important in designing mining operations that are ecologically acceptable. Here, we present the results of novelin situdeep sea plume experiments undertaken on the Tropic seamount, 300 nautical miles SSW of the Canary Islands. These plume experiments were accompanied by hydrographic and oceanographic field surveys and supported by detailed numerical modelling and high resolution video settling velocity measurements of thein situsediment undertaken in the laboratory. The plume experiments involved the controlled formation of benthic sediment plumes and measurement of the plume sediment concentration at a specially designed lander placed at set distances from the plume origin. The experiments were used as the basis for validation of a numerical dispersion model, which was then used to predict the dispersion of plumes generated by full-scale mining. The results highlight that the extent of dispersion of benthic sediment plumes, resulting from mining operations, is significantly reduced by the effects of flocculation, background turbidity and internal tides. These considerations must be taken into account when evaluating the impact and extent of benthic sediment plumes.