The Distribution of Particulate Trace Elements along a Meridional Transact in the Pacific

Particles are a key parameter for the GEOTRACES program because of their role as sources, sinks, and in the internal cycling of so many trace elements and isotopes (TEIs) (Geotraces 2006). Here we will present distribution of particulate trace elements in the 2018 GP15 Pacific Meridional Transect (PMT) from Alaska to Tahiti along 152 ^oW. During this cruise, approximately 390 particle samples were collected in two size fractions (0.8-51μm, >51 μm) using large-volume in-situ pumps. The GP15 transect crosses many hydrographic and productivity gradients, which are expected to cause large gradients in particle concentration, size fractionation, and composition. Moreover, the waters in this transect experience boundary inputs such as 1) runoffs and marginal sediments inputs from the Alaskan margin and Papua New Guinea margin through the Equatorial Undercurrent, 2) atmospheric mineral and anthropogenic aerosol deposition from Asia, and 3) hydrothermal inputs from up to four distinct sources (Juan de Fuca, Loihi, North East Pacific Rise, South East Pacific Rise). Our presentation will show TEIs concentrations in the small size fraction (0.8-51um) particles along the GP15 transect and discuss how the environmental gradients and boundary inputs affect the distribution of particulate TEIs.

Geotraces. 2006. GEOTRACES Science Plan. In Scientific Committee on Oceanic Research. http://www.geotraces.org/libraries/documents/Science_plan.pdf