Organic Matrices Help Preserve Iron At Sea | February 16, 2009 Issue - Vol. 87 Issue 7 | Chemical & Engineering News
Volume 87 Issue 7 | p. 41 | Concentrates
Issue Date: February 16, 2009

Organic Matrices Help Preserve Iron At Sea

Hydrothermal vents appear to pull in organic material from nearby flora and fauna to trap iron, possibly impacting ocean nutrient cycling
Department: Science & Technology
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The seafloor near the Tica hydrothermal vent of the East Pacific Rise.
Credit: Breea Govenar/WHOI
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The seafloor near the Tica hydrothermal vent of the East Pacific Rise.
Credit: Breea Govenar/WHOI
[+]Enlarge
The sediment trap used to collect particulate matter from the Tica hydrothermal vent.
Credit: Christopher German/WHOI
8707Wscon_ship
 
The sediment trap used to collect particulate matter from the Tica hydrothermal vent.
Credit: Christopher German/WHOI
Tube worms and other organisms near hydrothermal plumes may provide organic matter that stabilizes Fe(II).
Credit: Olivier Rouxel/WHOI
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Tube worms and other organisms near hydrothermal plumes may provide organic matter that stabilizes Fe(II).
Credit: Olivier Rouxel/WHOI

Hot-water plumes gushing into the ocean through seafloor hydrothermal vents have historically been viewed as inorganic systems. But new research suggests that the underwater geysers pull in organic material from nearby flora and fauna, a finding with implications for the geochemical cycling of nutrients (Nat. Geosci., DOI: 10.1038/ngeo433). A research team led by Brandy M. Toner, formerly of Woods Hole Oceanographic Institution and now of the University of Minnesota, Twin Cities, examined samples of particulate matter collected from the Tica vent at the East Pacific Rise by using scanning transmission X-ray microscopy and near-edge X-ray absorption fine structure spectroscopy. By weight, the samples contained an average of 6.7% particulate organic carbon, which likely came from biological debris. Some of the organic carbon was in the form of polymer-like matrices that appear to be composed of lipids, polysaccharides, and proteins. The matrices also incorporate Fe(II) and Fe(III), with the iron likely bound to organic functional groups through sorption or complexation. The researchers propose that the matrices prevent oxidation and precipitation of Fe(II), perhaps increasing its bioavailability as a deep-sea nutrient.

 
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