[Terry_Roll]

Biologically its a fantastic Super Oxide Dismutase, but if it gets into a mammalian system without being bound in Metallothionein, you'll end up with Parkinson's like symptoms.

Its possibly one of the reasons why some sea born mammals (whales) live for so long, considering its transported in much the same way as Iron.

I sometimes think the Victorians with their sea bathing were onto a thing or two because for humans, their greatest environmental exposure to Manganese is bathing in the sea, the concentration of Manganese is highest in coastal regions, despite the fact you can find the Manganese nodules out to sea on the sea bed. Cant help but notice that Uranium can also be found in similar sized nodules in certain geographical environments.

In terms of damage, this perhaps should be tackled like Oyster farming, so its a perfect case for using specialist drone equipment to do the harvesting, you cant deep sea dive farm these nodules.