North Atlantic Transect









The first major ocean section by the U. S. GEOTRACES program was completed in two legs:

Fall 2010 (Lisbon, Portugal to Mindelo, Cape Verde) and Fall 2011 (Woods Hole, MA to Bermuda to Praia, Cape Verde).

Chief Scientists: Ed Boyle (MIT), Bill Jenkins (WHOI) and Greg Cutter (Old Dominion University)


Within the context of this global survey of trace elements and isotopes (TEIs), our group from L-DEO is collaborating with

groups from the Woods Hole Oceanographic Institute, the University of Minnesota, and the University of Rhode Island

to complete analyses and interpretations of dissolved and particulate 231Pa, 230Th, and 232Th. This large data set will serve

many purposes including  validating 231Pa/230Th as a proxy for ocean circulation, calculating rates of removal by

scavenging, important for biogeochemical cycling of many insoluble trace elements, the chemical fractionation of

 231Pa/230Th due to the chemical composition of marine particles, and 232Th as a tracer of lithogenic supplies, such as

dust deposition.


Selected abstracts:

Hayes, C. T., R. F. Anderson, M. Q. Fleisher, L. F. Robinson, H. Cheng, R. L. Edwards, S. B. Moran (2012) Pa and Th

distributions along the GEOTRACES North Atlantic Transect. 2012 Ocean Sciences Meeting (Salt Lake City, Utah, February)


Robinson, L., K.-F. Huang, M. E. Auro, R. F. Anderson, C. T. Hayes, M. Q. Fleisher, H. Cheng, R. L. Edwards, S. B. Moran,

M. Saito (2012) Sources, sinks and cycling of seawater 232Th in the north and south Atlantic basins. (22nd V. M. Goldschmidt

Conference, Montreal, Canada, June).


Funding for this project from the National Science Foundation is acknowledged.


                                                                                      Photos: (above) The R/V Knorr departing Bermuda in November 2011 (credit B. Longworth)

Home                                                                            (Left) Sampling the Niskin Rossette for dissolved TEIs including Pa/Th (credit B. Sohst)

(Right) Lowering McLane pumps to sample particulate TEIs (credit B. Longworth)