Biological, Physical, and Atmospheric Controls on the Distribution of Cadmium and Its Isotopes in the Pacific Ocean Academic Article uri icon

abstract

  • AbstractDespite the Pacific being the location of the earliest seawater Cd studies, the processes which control Cd distributions in this region remain incompletely understood, largely due to the sparsity of data. Here, we present dissolved Cd and 114Cd data from the US GEOTRACES GP15 meridional transect along 152W from the Alaskan margin to the equatorial Pacific. Our examination of this region's surface ocean Cd isotope systematics is consistent with previous observations, showing a stark disparity between northern Cdrich highnutrient lowchlorophyll waters and Cddepleted waters of the subtropical and equatorial Pacific. Away from the margin, an open system model ably describes data in Cddepleted surface waters, but atmospheric inputs of isotopically light Cd likely play an important role in setting surface Cd isotope ratios (114Cd) at the lowest Cd concentrations. Below the surface, Southern Ocean processes and water mass mixing are the dominant control on Pacific Cd and 114Cd distributions. Cddepleted Antarctic Intermediate Water has a farreaching effect on North Pacific intermediate waters as far as 47N, contrasting with northernsourced Cd signatures in North Pacific Intermediate Water. Finally, we show that the previously identified negative Cd* signal at depth in the North Pacific is associated with the PO4 maximum and is thus a consequence of an integrated regeneration signal of Cd and PO4 at a slightly lower Cd:P ratio than the deep ocean ratio (0.35mmolmol1), rather than being related to in situ removal processes in lowoxygen waters.

published proceedings

  • GLOBAL BIOGEOCHEMICAL CYCLES

altmetric score

  • 1.5

author list (cited authors)

  • Sieber, M., Lanning, N. T., Bunnell, Z. B., Bian, X., Yang, S., Marsay, C. M., ... Conway, T. M.

citation count

  • 2

complete list of authors

  • Sieber, Matthias||Lanning, Nathan T||Bunnell, Zachary B||Bian, Xiaopeng||Yang, Shun-Chung||Marsay, Chris M||Landing, William M||Buck, Clifton S||Fitzsimmons, Jessica N||John, Seth G||Conway, Tim M

publication date

  • February 2023