Marine ferromanganese nodules and crusts containing Mn, Cu, Ni and Co in the most promising resource-grade concentrations and quantities, together with Fe and Zn (all elements of biogeochemical importance) are found far from land on the deep seafloor of the Pacific Ocean. The biogeochemical, chemical and physical mechanisms contributing to their formation, distribution, abundance and – for these six elements – variability in their concentrations in these deposits, are the main focus of the present review. The mechanisms addressed include biological productivity, sedimentation types and rates, bottom water characteristics, the Calcium Carbonate Compensation Depth, the depth and intensity of the oxygen minimum zone, and biogeochemical characteristics of the six focal elements. Particular attention is given to comparisons between the deposits found in the north and the south Pacific, in order to present an overarching view of our current understanding of the mechanisms that apply to both nodules and crusts in both oceanic hemispheres, including examination of the possible existence of a marine ferromanganese oxide continuum. The renewed interest in the commercial exploitation of these deposits has stimulated a welcome increase in scientific research that is essential to informing the public discourse on seabed mining. We briefly reflect on the work addressed in this review in that context.

中文翻译：

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太平洋资源级海洋铁锰结核和结壳的起源和变异：生物地球化学和物理控制综述

在远离陆地的太平洋深海海底发现了海洋铁锰结核和结壳，其中含有最有前景的资源级浓度和数量的锰、铜、镍和钴，以及铁和锌（所有具有生物地球化学重要性的元素）。影响其形成、分布、丰度的生物地球化学、化学和物理机制，以及这六种元素在这些沉积物中浓度的变化，是本综述的主要焦点。所涉及的机制包括生物生产力、沉积类型和速率、底层水特征、碳酸钙补偿深度、最低氧区的深度和强度以及六个焦点元素的生物地球化学特征。特别关注在北太平洋和南太平洋发现的沉积物之间的比较，以便提出我们目前对适用于两个大洋半球结核和地壳的机制的理解的总体观点，包括对可能存在的研究海洋氧化铁锰连续体。人们对这些矿床的商业开采重新产生了兴趣，刺激了科学研究的增加，这对于公众关于海底采矿的讨论至关重要。我们在此背景下简要回顾了本次审查中涉及的工作。