À partir d’une série exceptionnelle de 41 mois de mesures directes des dépôts atmosphériques en Guadeloupe, cette étude menée par Xu-Yang et al. quantifie les flux de 33 éléments traces et cherche à en déterminer l’origine. Les signatures isotopiques du strontium et du néodyme confirment que l’essentiel des poussières sahariennes atteignant la Guadeloupe provient de la région Libye–Algérie–Mali. D’autres éléments, notamment Se, Sb, Cu, Mo, As et Pb, témoignent en revanche de contributions anthropiques ou biologiques : les trajectoires atmosphériques suggèrent par exemple une origine nord-américaine ou européenne pour une partie de l’antimoine, tandis que le sélénium pourrait notamment provenir d’émissions biologiques de la mer des Sargasses. PDF
Abstract Dust, sea salt, and anthropogenic and biogenic particles in total atmospheric deposition are
sources of essential elements that can significantly impact biogeochemical cycles in the Atlantic Ocean and in
islands of the Caribbean region. This unique 41‐month data set records direct sampling of total atmospheric
deposition from March 2015 to August 2018 in Guadeloupe (North Tropical Atlantic Ocean). It quantifies the
total atmospheric deposition fluxes of 33 trace elements. Results on deposition samples for Sr and Nd isotopic
signatures are consistent with previous studies conducted in the Caribbean region based on aerosol samples,
confirming that trans‐Atlantic Saharan dust originated predominantly in the Libya‐Algeria‐Mali region of North
Africa. The REE composition is stable for the majority of samples, though some slight inter‐annual variation
was observed. Samples collected in 2016 present slightly different REE patterns compared to those collected in
2015, 2017, and 2018. A large fraction of some trace elements (Se, Sb, Cu, Mo, As, and Pb) may come from
biogenic sources or from atmospheric pollution occurring at the global level. Lead isotope ratios reveal a
mixture of transatlantic dust from the Libya‐Algeria‐Mali region, and anthropogenic sources with no clearly
defined region of origin. This result highlights the need for updated reviews of aerosol lead isotopic signatures
worldwide. Backward trajectory analysis suggests that atmospheric pollution from North America and Europe
may be a significant source of Sb, whereas biogenic gas from the Sargasso Sea may contribute to high levels
of Se.