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Dust storm frequencies and strengths were monitored during 2009 at various locations along the coast of the United Arab Emirates (UAE), as representative sites of the Arabian Gulf marine environment. The results have been compared with a pre-2009 five-year data set. Mineralogical components of dust samples collected during the 2009 study period were analyzed using both X-ray diffraction (XRD) and X-ray Fluorescence (XRF) techniques. The comparison of the 2009 and pre-2009 data revealed a shift in the characteristics of dust storms in the Arabian Gulf which may constitute a sensitive indicator of climate change affecting the region. The range of mineral compositions of the collected dust samples is consistent with temporally and spatially variable dust sources, associated with changing wind patterns over the Arabian Gulf From a positive perspective, the dust may deliver mineralogical nutrients enhancing microbial productivity in the marine ecosystem. Increasing productivity and liberation of iron from sediments will lead to an increase of Dimethyl Sulfide (DMS) in the atmosphere, which by oxidation will scatter solar radiation effectively with a consequent decrease in global temperature as a climate feedback.

Mineral dust deposits were collected at Mbour, Senegal, throughout the spring of 2006 and especially during the well-documented March 7-13 large Saharan dust outbreak. During this 7-day period, significant changes in mass flux, grain-size, clay mineralogy and Sr and Nd isotopic compositions were recorded, indicating distinct provenances for the dust transported and deposited during and outside the event. All these terrigenous proxies, as well as freshwater diatom taxa, also showed significant temporal variations during the outbreak, implying contributions from at least two different provenance regions. Tri-dimensional back-trajectories and satellite imaging enabled us to link those distinct signatures to regions increasingly to the southeast within a large area covering Mauritania, Mali and southern Algeria, identified by the Total Ozone Mapping Spectrometer (TOMS) as the main source of the prominent winter/spring plume over the tropical Atlantic. The multiproxy characterization of the March 7-13 dust fall therefore enables us to typify the terrigenous signature of two different regions supplying dust off West Africa, and provide valuable clues for the interpretation of Northeastern Tropical Atlantic Ocean dust sedimentary records in terms of changes in provenance regions and transport systems. Additionally, because dust deposition data are scarce, flux and grain size data obtained in this study, among other parameters such as clay assemblages, provide important constraints for atmospheric transport models and dust deposition budget estimates in this area.