The biogeochemical cycling of iron, copper, nickel, cadmium, manganese, cobalt, lead, and scandium in a California Current experimental study Academic Article uri icon

abstract

  • AbstractA 3day shipboard incubation experiment was conducted in the California Current System in July 2014 to investigate the cycling of iron (Fe), copper (Cu), nickel (Ni), cadmium (Cd), manganese (Mn), cobalt (Co), lead (Pb), and scandium (Sc) under a range of light and particle conditions. Filtered (< 0.2 m) and unfiltered treatments were incubated under the following light conditions: Dark, light (UV), and light without the ultraviolet (UV) wavelengths (noUV). The experiment was sampled for carbon and Fe uptake rates, dissolved trace metal concentrations (Fe, Cu, Ni, Cd, Mn, Co, Pb, Sc), Fe and Cu speciation, sizefractionated concentrations of Cd and Fe, and diatom community composition from DNA sequencing. Exposure to UV light increased phytoplankton Fe uptake in the first 24 h of the incubation relative to the noUV treatment, suggesting that a fraction of the ambient ligandbound Fe was photoreactive. Febinding organic ligand production was observed in the unfiltered light treatments in association with increasing chlorophyll a, and evidence for Cubinding ligand production in these treatments was also observed. Biological uptake of Cd and Co was observed along with scavenging of dissolved Pb. Manganese appeared to be rapidly oxidized by Mnoxidizing bacteria with concomitant drawdown of dissolved Ni. Scandium displayed similar trends to Fe, reinforcing the limited observations of the physicochemical similarities between these two elements in seawater. Overall, this study highlights distinct impacts of photochemical processes, scavenging, and biological effects on marine trace metal cycling in an environment characterized by seasonal upwelling.

published proceedings

  • LIMNOLOGY AND OCEANOGRAPHY

altmetric score

  • 1.5

author list (cited authors)

  • Mellett, T., Brown, M. T., Chappell, P. D., Duckham, C., Fitzsimmons, J. N., Till, C. P., ... Buck, K. N.

citation count

  • 17

complete list of authors

  • Mellett, Travis||Brown, Matthew T||Chappell, P Dreux||Duckham, Carolyn||Fitzsimmons, Jessica N||Till, Claire P||Sherrell, Robert M||Maldonado, Maria T||Buck, Kristen N

publication date

  • March 2018

publisher