Atmospheric deposition fluxes of 26 elements over the Southern Indian Ocean: Time series on Kerguelen and Crozet Islands

Atmospheric deposition of dust is suspected to have a significant impact on biogeochemical processes in high-nutrient-low-chlorophyll waters of the open ocean. In this study, we report time series of atmospheric deposition samples collected over two years at three different sites on Kerguelen and Crozet Islands in the Southern Indian Ocean. Total atmospheric deposition fluxes were measured for a large suite of elements (Al, As, Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Nd, Ni, Pb, Rb, S, Si, Sr, Ti, U, V, and Zn). Most of them are identified as coming from sea-salt or crustal sources, but enrichment factor variabilities of Pb, As, Cr, Cu, and V highlight an anthropogenic contribution during the austral winter for these five elements. For Al, Fe, Mn, and Si, deposition fluxes are similar for both Kerguelen and Crozet Islands. Fluxes for the other non-sea-salt elements exhibit differences below a factor of five with a decreasing gradient from Crozet to Kerguelen.