Global transport of airborne microbes over the tropical and subtropical oceans

The 9th International Workshop on Sand - Dust storm and Associated Dustfall (DUSTWORKSHOP9), 22-24 May 2018, Tenerife, Spain.-- 2 pagesAirborne particles comprise not only mineral dust but also a significant fraction of microbes and biogenic particles. Surveys of microbial diversity conducted in the last decades across all kinds of marine and terrestrial ecosystems have uncovered a striking diversity of microbial life. Yet, the abundance and composition of airborne microbial assemblages have received little attention as compared to terrestrial and marine environments. The few studies available focus mostly on continental or coastal air masses, while the organisms suspended in the atmosphere over the open oceans, which cover most of the Earth’s surface, remain unexplored. This study presents the first global survey of airborne microbes conducted over the Atlantic, Indian and Pacific Oceans during the Malaspina Circumnavigation Expedition. Thousands of taxonomically different microbes were found, uncovering a large diversity of airborne microbes comparable to that of terrestrial and marine environments. Our results show a large contribution of marine organisms to the total found in the global atmosphere, but also that terrestrial contributions make a large fraction of the airborne microorganisms found at remote marine locations. We estimate that atmospheric circulation may transfer microbes as fast as thousands of kilometers per day, sufficient to allow for intercontinental transport of microbesThis is a contribution to the Malaspina Expedition 2010, funded by the INGENIO 2010 CONSOLIDER program (ref. CDS2008-00077) of the Spanish Ministry of Economy and CompetitivenessPeer Reviewe