Comparison of the scavenging intensity, remineralization and residence time of Po and Pb at key zones (biotic, sediment-water and hydrothermal) along the East Pacific GEOTRACES transect.

The contrasting geochemical behavior of two long-lived progeny of Rn (daughter product of Ra), Po and Pb, provide valuable insights on the extent of recycling of biogenic particulate matter and their preferential removal from the water column. We collected and analyzed 135 water samples from six vertical profiles for Po and Pb as well as a suite of aerosol samples for Pb along the US GEOTRACES East Pacific Zonal Transect (GP16). Calculated atmospheric depositional flux of Pb from the measured Pb activity in aerosols exhibits an overall decrease from east to west along the cruise track.