Atmospheric Transport and Deposition of Particulate Material to the Oceans

Abstract

Winds carry billions of tons of natural and anthropogenic particulate matter (PM) from the continents to the oceans. The deposition of this eolian material is believed to affect important oceanic processes. Marine and atmospheric scientists are investigating the transport and deposition of PM to the oceans in order to better understand its impact on marine biogeochemical cycles. The flux of PM depends on many factors including the distribution of sources, the physical and chemical properties of the PM, meteorological conditions, and the rates of removal by dry and wet deposition. Atmospheric chemical transport models, coupled with in situ observations, are improving our understanding of the temporal and spatial variability of PM deposition. We present here a summary of the sources and composition of PM, a brief review of the mechanisms by which PM is removed from the atmosphere, and estimates of deposition rates of three classes of PM: mineral dust, selected trace elements, and nitrogen-containing compounds. The deposition of these materials is of great interest because of its suspected impact on primary productivity in the oceans and, in turn, the global carbon cycle. Of particular concern are the effects of climate change and increasing anthropogenic emissions.