Holly has just co-authored a short correspondence on Biodiversity Loss from Deep-Sea Mining in Nature Geosciences.  Based on an assessment of the four tiers of mitigation hierarchy (biodiversity loss should be avoided, minimized, remediated and — as a last resort — offset) the paper argues that mining with no net loss of biodiversity in the deep sea is probably an unattainable goal.  The latter aspect (offsetting) is difficult even in shallow waters –  the subject of Holly’s PhD work – and hard to envisage working in the deep-sea/international waters.