Publication Date:
2016-04-27
Description:
Hydrothermal vents emit sulphur and metals to the ocean1.
Particular attention has been paid to hydrothermal fluxes of
iron2–4, a limiting micronutrient of marine primary production5.
Vent-derived ironwas previously thought to rapidly oxidize and
precipitate around vents6. However, organic matter can bind
to and stabilize dissolved and particulate iron in hydrothermal
plumes7–9, facilitating its dispersion into the open ocean10.
Here, we report measurements of the chemical speciation of
sulphide and iron in high-temperature fluids emanating from
vents in the East Pacific Rise and the Eastern Lau Spreading
Center. We show that pyrite nanoparticles—composed of iron
and sulphur—account for up to 10% of the filterable iron
(less than 200nm in size) in these fluids. We suggest that
these particles form before the discharge of the vent fluid.
We estimate that pyrite nanoparticles sink more slowly than
larger plume particles, and are more resistant to oxidation than
dissolved Fe(II) and FeS.We suggest that the discharge of iron
in the form of pyrite nanoparticles increases the probability
that vent-derived iron will be transported over long distances
in the deep ocean.
Type:
Article
,
PeerReviewed
Format:
text
