How do the nodules form? I'm not sure of the mechanism but I can speculate that it may be that they form as a result of biological action of microorganisms whic

How do the nodules form? I'm not sure of the mechanism but I can speculate that it may be that they form as a result of biological action of microorganisms which take in seawater and secrete heavy metals. Colonies of these microorganisms could coalesce to the point where their presence is indicated by the presence of these nodules. Perhaps using thin sections of the nodules will provide a clue about their origin and whether they are a biological type of sedimentary deposit or something that occurs due to chemical or electrochemical diagenesis of existing sediments or alteration of suspended particulates in the water column. It's interesting that they are only found in areas where the seafloor is oxygenated according to the EOS article linked and quoted below. >Nodule provinces are not typically found in low-oxygen areas, she said. “However, there could be microenvironments where oxygen is depleted and dark oxygen production enables certain microbes, protozoa, or fauna.” If it is being produced down there, something is using it. Everything is part of a cycle and works in concert with all the other parts keep the wheels turning. If we remove enough parts the cycle ends. I think we need to understand the role these nodules play in their environments before commercial interests start crowing the familiar "national security interests" argument to allow them to bypass any scrutiny.