Atmospheric deposition constitutes an important input of trace elements to the surface ocean. The input of trace elements is of interest because some can be nutrients or toxicants, and others can serve to trace a wide range of oceanographic processes. This project is part of the US GEOTRACES program and its goal is to collect and characterize atmospheric deposition (dry and wet) during the US GEOTRACES Eastern Pacific Zonal Section cruise. The cruise track is along a region receiving one of the lowest atmospheric deposition in the global ocean, and provides a contrasting regime to characterize aerosol and rainfall chemistry as compared to the high atmospheric deposition region encountered and sampled during the US GEOTRACES North Atlantic Zonal Section. Additionally, collaborative studies are aimed to enhance chemical characterization, address the quantification of atmospheric deposition via chemical tracers, and to identifying the solubility and speciation of key trace elements and their isotopes after deposition.
Figure 1. Sampling Equipment used during the Pacific Zonal Section Cruise.
High volume (~1 m3 air/min) aerosol samplers deployed on 03 Deck of the R/V Thomas G. Thompson (~12 m above sea level), and the adaptors with filters used for aerosol collection.
Figure 2. Sampling region.
Map showing the percent of small aerosol particle along the cruise track (data from www.earthobservatory.nasa.gov). Map showing locations of aerosol sample collection (white numbers) and GEOTRACES station locations (black numbers).