Ed Boyle Earth Atmospheric and Planetary Sciences Massachusetts Institute of Technology Cambridge MA 02139 With thanks to: The International GEOTRACES Science Teams
GEOTRACES • The mission of the GEOTRACES program is to identify and quantify processes that control the distribution of key trace elements and isotopes in the ocean, and their sensitivity to changing environmental conditions.
What are ‘key elements? They include: • Those acting as micronutrients to control ocean productivity and ecosystems (e. g. Fe, Zn, Cd, Cu, Ni, Co, Mn) • Those tracing modern processes in the ocean (e. g. Al, Rare Earth Elements and Nd isotopes, Ra and Th isotopes, 3 He, 15 N, 230 Th & 232 Th, 13 C ) • Contaminants in the present and future ocean (e. g. Pb, Hg) • Chemical species used as proxies to reconstruct ocean conditions in the past (e. g. 231 Pa, 230 Th, Cd, Zn, 15 N, 30 Si, Ba, 13 C)
GEOTRACES framework
GEOTRACES Sections Yellow: completed sections Red: Forthcoming sections Black: GT contribution to IPY
Countries contributing to the GEOTRACES annual report to SCOR • • • • • • • Australia Belgium Brazil Canada China-Beijing China-Taipei Croatia France Germany India Ireland Italy Israel Japan Netherlands New Zealand Norway Poland Russia Slovenia South Africa Spain Sweden Tunisia United Kingdom United States GEOTRACES data are quality-controlled internationally, with two intercalibration pre-cruises, designated crossover stations, and sample sharing between laboratories GEOTRACES data is publically available, renewed in installments every 3 years Electronic Atlas: sections and 3 D rotating scenes: www. egeotraces. org Data: www. bodc. ac. uk/geotraces/data/idp 2014/
US-GEOTRACES North Atlantic Transect Outcome In total: > 17, 000 samples collected for 41 PIs for the measurement of over 100 properties
GEOTRACES GA-03 The U. S. North Atlantic Transect
Fe and Fe stable isotope ratios in the North Atlantic U. S. GEOTRACES transect Conway and John (2014) Nature 511: 212
230 Th and 231 Pa on the US GEOTRACES North Atlantic Transect Hayes et al. (2015) DSR 2 116: 29
Depth, m GEOTRACES GA 03: US GT 10, 11 North Atlantic Transect Pb Distance, km Noble et al. (2015) DSR 2 116: 208
Pb compared to SF 6 age (compute exponentially rising SF 6 equilibrium solubility with atmosphere and compare to concentration of seawater samples: Bill Smethie Noble et al. (2015) DSR 2 116: 208
3 -dimensional distribution of Pb in the Atlantic Ocean Graphics by Reiner Schlitzer
GEOTRACES GA 03: US GT 10, 11 North Atlantic Transect Pb Isotopes Noble et al. (2015) DSR 2 116: 208
Pb gasoline consumption 19301993 Boyle et al. (2014) Oceanography 27: 69
Bermuda Pb and Pb isotopes, 1880 -2000, from corals and recent seawater samples Boyle et al. (2014) Oceanography 27: 69
GEOTRACES GA 03: USGT 11 deepest stations compared to Bermuda Surface 1880 -2000 Noble et al. (2015) DSR 2 116: 208
3 He in the South Pacific at 2500 m John Lupton
South Pacific 3 He section at 15°S Lupton et al. 2003 John Lupton
East Pacific Rise Hydrothermal Plume seen in Fe, Mn, Al and 3 He Resing, Sedwick, German, Jenkins, Moffett, Sohst & Tagliabue (2015) Nature 523: 200
Pb scavenging in the East Pacific Rise hydrothermal plume Hydrothermal plume
Pb section in Indian Ocean Echegoyen et al. (2013) PNAS 111: 15328 Lee et al. (2015) GCA 170: 126 Lee (2013) Ph. D. thesis MIT/WHOI
Mercury distribution in the North Atlantic Lars-Eric Heimbürger, Daniel Cossa, Jeroen E. Sonke, Yanxu Zhang, Hélène Planquette, Francois Lacan, Pascale Lherminier, Geraldine Sarthou and the GEOVIDE science team
Summary GEOTRACES is halfway through the task mapping the global ocean distributions of hitherto sparsely determined trace elements, stable isotopes, and radioactive isotopes in the ocean. The data quality is excellent. International cooperation has been essential to good coverage and consistent data. Much of the data to date is publically available. • Electronic Atlas: sections and 3 D rotating scenes: www. egeotraces. org • Data: www. bodc. ac. uk/geotraces/data/idp 2014/
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