Distinct chemical and mineralogical composition of Icelandic dust compared to northern African and Asian dust
-
Published:2020-11-12
Issue:21
Volume:20
Page:13521-13539
-
ISSN:1680-7324
-
Container-title:Atmospheric Chemistry and Physics
-
language:en
-
Short-container-title:Atmos. Chem. Phys.
Author:
Baldo ClarissaORCID, Formenti PaolaORCID, Nowak Sophie, Chevaillier Servanne, Cazaunau Mathieu, Pangui Edouard, Di Biagio ClaudiaORCID, Doussin Jean-FrancoisORCID, Ignatyev KonstantinORCID, Dagsson-Waldhauserova PavlaORCID, Arnalds Olafur, MacKenzie A. RobertORCID, Shi Zongbo
Abstract
Abstract. Iceland is a highly active source of natural dust.
Icelandic dust has the potential to directly affect the climate via
dust–radiation interaction and indirectly via dust–cloud interaction,
the snow/ice albedo effect and impacts on biogeochemical cycles. The impacts of
Icelandic dust depend on its mineralogical and chemical composition.
However, a lack of data has prevented an accurate assessment of the role of
Icelandic dust in the Earth system. Here, we collected surface sediment
samples from five major Icelandic dust hotspots. Dust aerosols were
generated and suspended in atmospheric chambers, and PM10 and PM20
fractions were collected for further analysis. We found that the dust
samples primarily consist of amorphous basaltic materials ranging from 8 wt %
(from the Hagavatn hotspot) to 60 wt %–90 wt % (other hotspots). Samples
had relatively high total Fe content (10 wt %–13 wt %). Sequential extraction
of Fe to determine its chemical form shows that dithionite Fe (Fe oxides
such as hematite and goethite) and ascorbate Fe (amorphous Fe) contribute
respectively 1 %–6 % and 0.3 %–1.4 % to the total Fe in Icelandic dust. The
magnetite fraction is 7 %–15 % of total Fe and 1 %–2 wt % of PM10,
which is orders of magnitude higher than in mineral dust from northern Africa.
Nevertheless, about 80 %–90% of the Fe is contained in pyroxene and
amorphous glass. The initial Fe solubility (ammonium acetate extraction at
pH 4.7) is from 0.08 % to 0.6 %, which is comparable to low-latitude dust such
as that from northern Africa. The Fe solubility at low pH (i.e. pH 2) is
significantly higher than typical low-latitude dust (up to 30 % at pH 2
after 72 h). Our results revealed the fundamental differences in
composition and mineralogy of Icelandic dust from low-latitude dust. We
attribute these differences to the low degree of chemical weathering, the
basaltic composition of the parent sediments and glacial processes.
Icelandic dust contributes to the atmospheric deposition of soluble Fe and
can impact primary productivity in the North Atlantic Ocean. The distinct
chemical and mineralogical composition, particularly the high magnetite
content (1 wt %–2 wt %), indicates a potentially significant impact of
Icelandic dust on the radiation balance in the subpolar and polar regions.
Funder
European Cooperation in Science and Technology Horizon 2020 Natural Environment Research Council
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference138 articles.
1. 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.: Natural
iron fertilization by the Eyjafjallajökull volcanic eruption,
Geophys. Res. Lett., 40, 921–926, https://doi.org/10.1002/grl.50221, 2013. 2. Arimoto, R.: Eolian dust and climate: relationships to sources, tropospheric
chemistry, transport and deposition, Earth-Sci. Rev., 54, 29–42, https://doi.org/10.1016/s0012-8252(01)00040-x, 2001. 3. Arnalds, O.: Dust sources and deposition of aeolian materials in Iceland,
Iceland. Agr. Sci., 23, 3–21, 2010. 4. Arnalds, O.: The soils of Iceland, World Soils Book Series, Springer,
Dordrecht, ISBN 978-94-017-9620-0, 2015. 5. Arnalds, O., Gisladottir, F. O., and Sigurjonsson, H.: Sandy deserts of
Iceland: an overview, J. Arid Environ., 47, 359–371, https://doi.org/10.1006/jare.2000.0680, 2001.
Cited by
30 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|