Enhanced primary production following the eruption of an Icelandic volcano

Hallo MOOCers,

This article is brought to you by Ms Jessica Klar, a PhD. candidate (Geochemistry Group) here at the National Oceanography Centre.
Jessica’s Klar NOC profile page: http://noc.ac.uk/people/jk2e09

Many of you might remember the European flight disruptions caused by the volcanic eruption of Eyjafjallajökull (Iceland) from the 14th of April to the 22nd of May 2010. Approximately 270 ± 70 ⋅ 106 m3 of volcanic ash loaded with metals got expelled into the atmosphere and spread south-eastward over the Ocean and Europe.

Satellite image of the volcanic ash plume spreading in the atmosphere over the ocean

 

Ash fall-out might have had a significant influence on the primary production in the high latitude North Atlantic Ocean. We had the very rare opportunity to investigate trace metal distributions and primary production rates in this area at the time of eruption during three cruises on the RRS Discovery.

View of the erupting volcano from RRS Discovery
View of the erupting volcano from RRS Discovery

 

The high latitude North Atlantic Ocean is described as a seasonal HNLC (high nutrient, low chlorophyll) region, where iron stress develops in the peak and post bloom stages during summer. Primary production can only be stimulated by ash if it adds a previously limiting nutrient to the surface ocean. During the volcanic eruption highly elevated concentrations of dissolved iron (an essential micronutrient for marine phytoplankton) and dissolved aluminium (a tracer for aerosol inputs), as well as high photosynthetic efficiencies, were observed directly under the plume. Ash addition experiments have also shown enhancement of primary production.

Modeled dissolved iron enhancement (nM) as a result of ash deposition
Modeled dissolved iron enhancement (nM) as a result of ash deposition

 

Due to the intermittent and unpredictable nature of volcanic eruptions it is difficult to quantify its impacts on trace metal cycling in the oceans. Volcanic ash is loaded in metals and its supply to the surface ocean promotes primary production on a local and sporadic scale, hence enhancing atmospheric carbon drawdown.

Sampling directly under the volcanic ash plume in the Atlantic Ocean
Sampling directly under the volcanic ash plume in the Atlantic Ocean

 

You can find more information about this study in the following article:

Achterberg, E P, Moore, C M, Henson, S A, Steigenberger, S, Stohl, A, Eckhardt, S, Avendano, L C, Cassidy, M, Hembury, D, Klar, J K, Lucas, M I, Macey, A I, Marsay, C M and Ryan-Keogh, T J, 2013. Natural iron fertilization by the Eyjafjallajökull volcanic eruption. Geophysical Research Letters, 40, 921-926.

 

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