Articles | Volume 11, issue 23
https://doi.org/10.5194/bg-11-6623-2014
https://doi.org/10.5194/bg-11-6623-2014
Research article
 | 
02 Dec 2014
Research article |  | 02 Dec 2014

Quantification of iron-rich volcanogenic dust emissions and deposition over the ocean from Icelandic dust sources

O. Arnalds, H. Olafsson, and P. Dagsson-Waldhauserova

Abstract. Iceland has extremely active dust sources that result in large-scale emissions and deposition on land and at sea. The dust has a volcanogenic origin of basaltic composition with about 10% Fe content. We used two independent methods to quantify dust emission from Iceland and dust deposition at sea. Firstly, the aerial extent (map) of deposition on land was extended to ocean areas around Iceland. Secondly, surveys of the number of dust events over the past decades and calculations of emissions and sea deposition for the dust storms were made. The results show that total emissions range from 30.5 (dust-event-based calculation) to 40.1 million t yr−1 (map calculation), which places Iceland among the most active dust sources on Earth. Ocean deposition ranges between 5.5 (dust event calculations) and 13.8 million tons (map calculation). Calculated iron deposition from Icelandic dust ranges between 0.567 and 1.4 million tons, which are distributed over wide areas (>370 000 km2) and consist of fine reactive volcanic materials. The paper provides the first quantitative estimate of total dust emissions and oceanic deposition from Iceland. Iron is a limiting nutrient for primary production in the oceans around Iceland, and the dust is likely to affect Fe levels in Icelandic ocean waters.

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Short summary
Iceland is one of the largest dust sources on Earth. Based on two separate methods, we estimate dust emissions to range between 30 and 40 million tons annually. Ocean deposition ranges between 5.5 and 13.8 million tons. Calculated iron deposition in oceans around Iceland ranges between 0.56 to 1.4 million tons, which are distributed over wide areas. Iron is a limiting nutrient for primary production in these waters, and dust is likely to affect oceanic Fe levels around Iceland.
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