Abstract
A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river-influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high-resolution pan-Arctic survey of carbon, nutrients, and a suite of trace elements and isotopes (TEIs). The cruises bisected the TPD at two locations in the central basin, which were defined by maxima in meteoric water and dissolved organic carbon concentrations that spanned 600 km horizontally and ~25–50 m vertically. Dissolved TEIs such as Fe, Co, Ni, Cu, Hg, Nd, and Th, which are generally particle-reactive but can be complexed by organic matter, were observed at concentrations much higher than expected for the open ocean setting. Other trace element concentrations such as Al, V, Ga, and Pb were lower than expected due to scavenging over the productive East Siberian and Laptev shelf seas. Using a combination of radionuclide tracers and ice drift modeling, the transport rate for the core of the TPD was estimated at 0.9 ± 0.4 Sv (106 m3 s−1). This rate was used to derive the mass flux for TEIs that were enriched in the TPD, revealing the importance of lateral transport in supplying materials beneath the ice to the central Arctic Ocean and potentially to the North Atlantic Ocean via Fram Strait. Continued intensification of the Arctic hydrologic cycle and permafrost degradation will likely lead to an increase in the flux of TEIs into the Arctic Ocean.
| Original language | English (US) |
|---|---|
| Article number | e2019JC015920 |
| Journal | Journal of Geophysical Research: Oceans |
| Volume | 125 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 1 2020 |
Bibliographical note
Funding Information:The authors thank the Editor and two anonymous reviewers for their constructive comments and feedback. This study would not have been possible without the dedication of the captains and crews of the USCGC and R/V . The authors also thank the many members of the shipboard scientific parties, including the chief scientists, who enabled sample collection via the various CTD rosette and in situ pumping systems, as well as the sample analyses on the ship and back in their home laboratories. Funding for Arctic GEOTRACES was provided by the U.S. National Science Foundation, Swedish Research Council Formas, French Agence Nationale de la Recherche and LabexMER, Netherlands Organization for Scientific Research, and Independent Research Fund Denmark. Data from GEOTRACES cruises GN01 (HLY1502) and GN04 (PS94) have been archived at the Biological and Chemical Oceanography Data Management Office (Biological and Chemical Oceanography Data Management Office (BCO‐DMO); https://www.bco-dmo.org/deployment/638807 ) and PANGAEA ( https://www.pangaea.de/?q=PS94&f.campaign%5B%5D=PS94 ) websites, respectively. The inorganic carbon data are available at the NOAA Ocean Carbon Data System (OCADS; doi: 10.3334/CDIAC/OTG.CLIVAR_ARC01_33HQ20150809 ). In addition to these national data archives, the data used in this paper is available as supporting information. Healy Polarstern
Funding Information:
The authors thank the Editor and two anonymous reviewers for their constructive comments and feedback. This study would not have been possible without the dedication of the captains and crews of the USCGC Healy and R/V Polarstern. The authors also thank the many members of the shipboard scientific parties, including the chief scientists, who enabled sample collection via the various CTD rosette and in situ pumping systems, as well as the sample analyses on the ship and back in their home laboratories. Funding for Arctic GEOTRACES was provided by the U.S. National Science Foundation, Swedish Research Council Formas, French Agence Nationale de la Recherche and LabexMER, Netherlands Organization for Scientific Research, and Independent Research Fund Denmark. Data from GEOTRACES cruises GN01 (HLY1502) and GN04 (PS94) have been archived at the Biological and Chemical Oceanography Data Management Office (Biological and Chemical Oceanography Data Management Office (BCO-DMO); https://www.bco-dmo.org/deployment/638807) and PANGAEA (https://www.pangaea.de/?q=PS94&f.campaign%5B%5D=PS94) websites, respectively. The inorganic carbon data are available at the NOAA Ocean Carbon Data System (OCADS; doi:10.3334/CDIAC/OTG.CLIVAR_ARC01_33HQ20150809). In addition to these national data archives, the data used in this paper is available as supporting information.
Publisher Copyright:
©2020. American Geophysical Union. All Rights Reserved.
Keywords
- Arctic Ocean
- GEOTRACES]
- Transpolar Drift
- carbon
- nutrients
- trace elements