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So it appears that the authors actually don't know. Specifically they say: Whereas questions remain concerning this potential mechanism (such as the identity o

So it appears that the authors actually don't know. Specifically they say: Whereas questions remain concerning this potential mechanism (such as the identity of the energy source(s), longevity of DOP, catalytic stabilities, electrochemical conditions on exposed versus buried nodules surfaces and the influence of different chemistries within the nodule layers And after reading their explanation for why they discount microbial sourcing of the oxygen, I am inclined to join other commenters in their skepticism. Given no good mechanistic understanding, I think they are being too quick to rule out microbes. That's not to say that they are wrong, just that I think their current evidence isn't strong enough to support the claims they are making (admittedly this is a completely subjective assessment)

aaron695 2y ago
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simpaticoder 2y ago
I believe electrolysis occurs between any two metals in a fluid conductor (like salt water). This happens in boats, which is why you put a "sacraficial zinc" on the hull so that your prop and prop shaft and through-hulls don't erode. Maybe this could generate small amounts of O2 at depth, but not a chemist so I don't know.
- MostlyStable 2y ago
  As you point out, that causes corrosion, using up the metals (well, using up their galvanic potential energy anyways). These nodules are A) extremely old and B) extremely slow growing/generating. If that were the source of the electric fields, it couldn't be sustained long enough to be a stable source and it would result in the nodules corroding away (or at least one of the metals corroding until there was no longer electrochemical potential, which would end the effect). In other words, for that to be the source, then that would imply that something about our understanding of how these nodules form would be off by many orders of magnitude. They would have to be forming so quickly, that the concerns about using them up would almost go away (assuming that harvesting didn't disrupt the process of formation that is). Part of the reason why there is concern here is that these nodules (as we currently understand it) form so slowly (literally millions of years), that if we harvest them, then they are, for all intents and purposes, gone forever. So if they do have important ecological functions, then those functions are completely wiped out. But if they are actually forming on the order years (and I can't imagine that it could possibly be any slower than that for galvanic/corrosive processes to be the answer, and in fact probably faster), then that concern goes away. Harvest one section of a field, go away for a decade, and it's restored.

aaron695 2y ago

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simpaticoder 2y ago

I believe electrolysis occurs between any two metals in a fluid conductor (like salt water). This happens in boats, which is why you put a "sacraficial zinc" on the hull so that your prop and prop shaft and through-hulls don't erode. Maybe this could generate small amounts of O2 at depth, but not a chemist so I don't know.

MostlyStable 2y ago
As you point out, that causes corrosion, using up the metals (well, using up their galvanic potential energy anyways). These nodules are A) extremely old and B) extremely slow growing/generating. If that were the source of the electric fields, it couldn't be sustained long enough to be a stable source and it would result in the nodules corroding away (or at least one of the metals corroding until there was no longer electrochemical potential, which would end the effect). In other words, for that to be the source, then that would imply that something about our understanding of how these nodules form would be off by many orders of magnitude. They would have to be forming so quickly, that the concerns about using them up would almost go away (assuming that harvesting didn't disrupt the process of formation that is). Part of the reason why there is concern here is that these nodules (as we currently understand it) form so slowly (literally millions of years), that if we harvest them, then they are, for all intents and purposes, gone forever. So if they do have important ecological functions, then those functions are completely wiped out. But if they are actually forming on the order years (and I can't imagine that it could possibly be any slower than that for galvanic/corrosive processes to be the answer, and in fact probably faster), then that concern goes away. Harvest one section of a field, go away for a decade, and it's restored.