Dissolved and Particulate Trace Elements in Late Summer Arctic Melt Ponds

Authors

Chris M. Marsay, University of Georgia
Ana Aguilar-Islas, University of Alaska, Fairbanks
Jessica N. Fitzsimmons, Texas A&M UniversityFollow
Mariko Hatta, University of Hawaii, ManoaFollow
Laramie T. Jensen, Texas A&M University
Seth G. John, University of Southern CaliforniaFollow
David Kadko, Florida International UniversityFollow
William M. Landing, Florida State University
Nathan T. Lanning, Texas A&M University
Peter L. Morton, National High Magnetic Field Laboratory
Angelica Pasqualini, Columbia University
Sara Rauschenberg, Bigelow Laboratory for Ocean Sciences
Robert M. Sherrell, Rutgers University
Alan M. Shiller, University of Southern MississippiFollow
Benjamin S. Twining, Bigelow Laboratory for Ocean SciencesFollow
Laura M. Whitmore, University of Southern MississippiFollow
Ruifeng Zhang, University of Southern California
Clifton S. Buck, University of GeorgiaFollow

Document Type

Article

Publication Date

8-20-2018

Department

Marine Science

Abstract

Melt ponds are a prominent feature of Arctic sea ice during the summer and play a role in the complex interface between the atmosphere, cryosphere and surface ocean. During melt pond formation and development, micronutrient and contaminant trace elements (TEs) from seasonally accumulated atmospheric deposition are mixed with entrained sedimentary and marine-derived material before being released to the surface ocean during sea ice melting. Here we present particulate and size-fractionated dissolved (truly soluble and colloidal) TE data from five melt ponds sampled in late summer 2015, during the US Arctic GEOTRACES (GN01) cruise. Analyses of salinity, δ¹⁸O, and ⁷Be indicate variable contributions to the melt ponds from snowmelt, melting sea ice, and surface seawater. Our data highlight the complex TE biogeochemistry of late summer Arctic melt ponds and the variable importance of different sources for specific TEs. Dissolved TE concentrations indicate a strong influence from seawater intrusion for V, Ni, Cu, Cd, and Ba. Ultrafiltration methods reveal dissolved Fe, Zn, and Pb to be mostly colloidal (0.003–0.2 μm), while Mn, Co, Ni, Cu, and Cd are dominated by a truly soluble (aerosols and/or sedimentary material, with significant enrichments for some elements, including Ni, Cu, Zn, Cd and Pb, that may result from anthropogenic aerosols, biogenic material, and/or in situ scavenging of dissolved TEs. Our results indicate that melt ponds represent a transitional environment in which some atmospherically-derived TEs undergo physical and/or chemical changes before their release to the surface ocean. As a result, the ongoing changes in sea ice areal extent, thickness, and melt season length are likely to influence the bioavailability of atmospheric TE input to the surface Arctic Ocean, with material released from snow and sea ice via melt ponds earlier in the summer and with more extensive direct deposition to the ocean surface.

Publication Title

Marine Chemistry

Volume

204

First Page

70

Last Page

85

Recommended Citation

Marsay, C. M., Aguilar-Islas, A., Fitzsimmons, J. N., Hatta, M., Jensen, L. T., John, S. G., Kadko, D., Landing, W. M., Lanning, N. T., Morton, P. L., Pasqualini, A., Rauschenberg, S., Sherrell, R. M., Shiller, A. M., Twining, B. S., Whitmore, L. M., Zhang, R., Buck, C. S. (2018). Dissolved and Particulate Trace Elements in Late Summer Arctic Melt Ponds. Marine Chemistry, 204, 70-85.
Available at: https://aquila.usm.edu/fac_pubs/15420