Eyjafjallajokull's iron-rich ash fertilized North Atlantic Ocean

In about a third of the global ocean, the abundance of life is limited by a dearth of biologically available iron. The supply of iron to a region that is depleted in this important nutrient can stimulate algal productivity, and can result in a temporary boom in biological activity. For much of the surface ocean, the wind-borne transport of iron-rich dust and the upwelling of nutrient-filled water are the major sources of iron.

Another potentially important source is the deposition of the iron-rich ash produced by volcanic eruptions. Though satellite observations and modeling work suggest that could seed life in such a way, there have been only a limited number of direct observations of the effects of ash deposition on waters.

Thanks to a bit of serendipitous scheduling, Achterberg et al. conducted a series of research cruises in the Iceland Basin region of the both during and after the month-long eruption of Iceland's Eyjafjallajökull volcano in the spring of 2010. Three cruises allowed the authors to undertake measurements of surface ocean iron concentration before, during, and after the eruption in a region directly affected by the towering . Beneath the plume, the authors found peak dissolved iron concentrations up to 10.2 nanomolar, compared to 0.23 to 0.45 nanomolar detected before ash deposition.

Using a model of the ash plume trajectory and ash deposition rates, along with measurements of iron dissolution, the authors calculated that up to 570,000 square kilometers (220,000 square miles) of North Atlantic waters could have been seeded with at least 0.2 nanomolar of iron. In controlled biological incubation experiments, the authors added volcanic ash collected under the plume to sea water, and find that iron leached from the ash could drive an increase in and a draw-down of nutrient levels.


Explore further

Scientists measure impact of volcanic ash on ocean biology

More information: Natural iron fertilisation by the Eyjafjallajökull volcanic eruptionGeophysical Research Letters, doi:10.1002/grl.50221, 2013
Journal information: Geophysical Research Letters

Citation: Eyjafjallajokull's iron-rich ash fertilized North Atlantic Ocean (2013, March 12) retrieved 21 September 2019 from https://phys.org/news/2013-03-eyjafjallajokull-iron-rich-ash-fertilized-north.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
0 shares

Feedback to editors

User comments

Mar 13, 2013
So the Sahara had to die so that the oceans could live?

Mar 13, 2013
Only if the Sahara is rich in iron.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more