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

O Arnalds,P Dagsson-Waldhauserova,H Olafsson

doi:10.5194/bg-11-6623-2014

O Arnalds, P Dagsson-Waldhauserova + Show 1 more

Open Access

https://doi.org/10.5194/bg-11-6623-2014

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Abstract

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.

Highlights

Dust emissions from barren areas have pronounced influences on Earth’s terrestrial and oceanic ecosystems, the atmosphere, climate and human health (Field et al, 2010; Ayris and Delmelle, 2012a)
Research shows frequent dust storms in South Iceland moving into the North Atlantic Ocean (Arnalds and Metúsalemsson, 2004; Prospero et al, 2012) and into the Arctic from Northeast Iceland (Dagsson-Waldhauserova et al, 2013a), and it has been suggested that Iceland is among the world’s most active dust sources (Arnalds, 2010; Prospero et al, 2012; Blechschmidt et al, 2012; Bullard, 2013)
Our research indicates that total emissions of dust from Icelandic dust sources are in the range of 30–40 million tons annually, with the majority of the sediments deposited on land

Summary

Introduction

Dust emissions from barren areas have pronounced influences on Earth’s terrestrial and oceanic ecosystems, the atmosphere, climate and human health (Field et al, 2010; Ayris and Delmelle, 2012a). Global estimates of mean annual dust emissions range from 500 to 5000 million tons per year, with most estimates between 1000 and 2000 million tons, but the global oceans are commonly estimated to receive 300–500 million tons (reviewed by Engelstaedter et al, 2006). Dust production is mainly attributed to unstable barren areas in dry climates, with northern Africa being the largest contributor of dust to the atmosphere (Engelstaedter et al, 2006). Dust emissions from the Arctic and Antarctic have received increased attention (Arnalds, 2010; Bullard, 2013; Gillies et al, 2013; Muhs et al, 2013). Research shows frequent dust storms in South Iceland moving into the North Atlantic Ocean (Arnalds and Metúsalemsson, 2004; Prospero et al, 2012) and into the Arctic from Northeast Iceland (Dagsson-Waldhauserova et al, 2013a), and it has been suggested that Iceland is among the world’s most active dust sources (Arnalds, 2010; Prospero et al, 2012; Blechschmidt et al, 2012; Bullard, 2013)

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