The importance of shallow hydrothermal island arc systems in ocean biogeochemistry
Hawkes, J.A.; Connelly, D.P.; Rijkenberg, M.J.A.; Achterberg, E.P. (2014). The importance of shallow hydrothermal island arc systems in ocean biogeochemistry. Geophys. Res. Lett. 41(3): 942-947. dx.doi.org/10.1002/2013GL058817 In: Geophysical Research Letters. American Geophysical Union: Washington. ISSN 0094-8276; e-ISSN 1944-8007, more |   |
| Author keywords | iron; hydrothermal; colloid; island arc; scavenging; caldera |
| Authors | | Top | - Hawkes, J.A.
- Connelly, D.P.
- Rijkenberg, M.J.A., more
- Achterberg, E.P.
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| Abstract | Hydrothermal venting often occurs at submarine volcanic calderas on island arc chains, typically at shallower depths than mid-ocean ridges. The effect of these systems on ocean biogeochemistry has been under-investigated to date. Here we show that hydrothermal effluent from an island arc caldera was rich in Fe(III) colloids (0.02-0.2 mu m; 46% of total Fe), contributing to a fraction of hydrothermal Fe that was stable in ocean water. Iron(III) colloids from island arc calderas may be transferred into surrounding waters (generally 0-1500m depth) by ocean currents, thereby potentially stimulating surface ocean primary productivity. Hydrothermal Fe oxyhydroxide particles (>0.2 mu m) were also pervasive in the studied caldera and contained high concentrations of oxyanions of phosphorus (P), vanadium (V), arsenic (As), and manganese (Mn). Hydrothermal island arcs may be responsible for>50% of global hydrothermal P scavenging and>40% V scavenging, despite representing <10% of global hydrothermal fluid flow.
Key Points
A large portion of iron from hydrothermal island arc calderas exists as colloids These colloids coprecipitate important amounts of dissolved oxyanions Iron colloids from hydrothermal island arcs may stimulate primary productivity |
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