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Atmospheric deposition over the Caribbean region: sea salt and Saharan dust are sources of essential elements on the island of Guadeloupe
  • Yangjunjie XU,
  • Celine Dessert,
  • Rémi Losno
Yangjunjie XU
Université Paris Cité, Institut de Physisque du Globe de Paris

Corresponding Author:[email protected]

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Celine Dessert
Univ. Paris Diderot - Sorbonne Paris Cite- IPGP
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Rémi Losno
Universite de Paris - IPGP
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Abstract

Dust emitted from North Africa is transported over long distances and has a strong impact on large areas over the North Tropical Atlantic Ocean. Sea salt emitted by the sea surface is the second source of essential elements transported in the atmosphere and plays a major role in the cycles of alkaline-earth metals in the ecosystems of tropical North Atlantic Islands. The total atmospheric deposition fluxes were continuously sampled on a weekly basis in Guadeloupe, Lesser Antilles, from March 2015 to August 2018 (41 months). Elemental deposition fluxes including Al, Ca, K, Mg, Fe, Na, P, S, and Zn were measured for all samples in order to provide the first long time series of atmospheric elemental deposition fluxes over the Lesser Antilles region. It is shown that: (i) the three sources of atmospheric deposits in Guadeloupe for the presented elements are sea salt (for K, Ca, Mg, Na, S), long-range transported Saharan dust (for Al, Ca, K, Fe), and biogenic particles (for P and Zn); (ii) the average deposition mass fluxes of sea salt and Saharan dust are 16.7 g.m-2.year-1 and 10.6 g.m-2.year-1, respectively, without noticeable inter-annual variations; (iii) a pronounced seasonality is found for the Saharan dust deposition, for which maximum flux values are observed between June and July each year and 85% of the annual deposition flux occurs between April and September; (iv) the deposition flux of sea salt is strongly correlated to local wind speed, without seasonality.