Overview

• The PLOS Biology study explains how the west Pacific vent worm precipitates arsenic sulfide inside epidermal vacuoles as bright yellow granules.
• Microscopy, spectroscopy and Raman analyses identified the granules as orpiment (As2S3), forming a microscopic protective layer on the worm’s skin and along internal tissues.
• Arsenic burdens can surpass 1% of body weight in this species, with the mineralized form considered less bioavailable than dissolved arsenic and sulfide.
• Proteomic evidence implicates membrane transporters and hemoglobin-bearing vacuoles in shuttling arsenic and hydrogen sulfide into sites of mineral formation.
• The worm is the only animal reported from the hottest vent zones, and similar arsenic hyperaccumulation in related worms and some snails suggests the tactic may be broader even as the exact transport pathways remain unknown.