ANNUAL REPORT ON GEOTRACES ACTIVITIES IN UNITED …

1 ANNUAL REPORT ON GEOTRACES ACTIVITIES IN UNITED kingdom May 1st, 2016 to April 30th, 2017 New scientific results Bloom and Bust! 2016-7 was the year in which the key role of Southern Ocean diatoms in coupling the global ocean nutrient distributions of silicon and zinc was demonstrated. Published in Nature Geoscience, this new study resolved a long-standing puzzle in ocean biogeochemistry, and serves to reemphasize the importance of the Southern Ocean in whole ocean carbon cycling. Vance, D., Little, et al. (2017), Nature Geoscience. New insights into the functioning of the ocean iron cycle made in recent years has led to a revised view of the controls on the oceanic cycling of iron. This new vision places unique constraints on the ocean biogeochemical models we rely on for exploring hypotheses and projecting the impacts of change.

2 A set of priorities for furthering our understanding in the coming years were articulated that can set the agenda for transformation in understanding that can allow us to ultimately place iron within the context of a unifying theory of resource cycling in the ocean. Tagliabue, A et al. (2017), Nature. The spring-time growth and decomposition of ocean phytoplankton enhances the consumption of oxygen and the release of an important nutrient , dissolved iron, by shelf sediments. Klar and co-workers found dissolved iron that escaped the seafloor was unusually persistent in oxygen-rich shelf seawater of the UK, and suggest it results from the supply of organic compounds from the sediments, which can bind iron and enhance its solubilty in the ocean.

3 Klar, et al. (2017), Biogeochemistry. Following the near complete global cessation of leaded petrol use, Bridgestock and colleagues have found that up to 30-50% of natural Pb, derived from mineral dust, can now be found in tropical Atlantic surface waters. By measuring the Pb isotope signature of surface waters and aerosols, the success of the phase out of leaded gasoline could be documented. The tropical Atlantic is however an area of particularly high mineral dust flux, and overall anthropogenic ACTIVITIES will remain the dominant source of Pb to most other areas in the global ocean. Bridgestock et al., (2016), Nature Communications. What constraints the hydrothermal dissolved iron isotopic signature? Lough, et al. (2017), Geochimica et Cosmochimica Acta.

4 What controls hydrothermal plume transport of iron over 4000 km in the deep Pacific Ocean? Homoky, (2017), Nature Geoscience, News and Views. Figure 18. The dynamic balance of iron dispersed in a hydrothermal plume. New publications (published or in press) Baker, & Jickells, (2016). Atmospheric deposition of soluble trace elements along the Atlantic Meridional Transect (AMT). Progress in Oceanography, Baker, , Landing, , Bucciarelli, E., Cheize, M., Fietz, S., Hayes, , Kadko, D., Morton, , Rogan, N., Sarthou, G., Shelley, , Shi, Z., Shiller, A. & van Hulten, (2016). Trace element and isotope deposition across the air-sea interface: progress and research needs. Phil. Trans. R. Soc. A, 374 (2081), Boyd, , Ellwood, M.

5 , Tagliabue, A. & Twining, (2017). Biotic and abiotic retention, recycling, and remineralisation of metals in the ocean. Nature Geoscience, Bridgestock, L., van de Flierdt, T., Rehk mper, M., Paul, M., Middag, R., Milne, A., Lohan, , Baker, , Chance, R., Khondoker, R., Strekopytov, S., Humphreys-Williams, E., Achterberg, , Rijkenberg, , Gerringa, & de Baar, (2016), Return of naturally sourced Pb to Atlantic surface waters. Nature Communications, 7, Bridgestock, L., Rehk mper, M., van de Flierdt, T., Murphy, K., Khondoker, R., Baker, , Chance, R. & Achterberg, (2017), The Cd isotope composition of atmospheric aerosols from the Tropical Atlantic Ocean. Geophysical Research Letters, 44, Casacuberta, N.

6 , Masqu , P., Henderson, G., Rutgers van der Loeff, M., Bauch, D., Vockenhuber, C., Daraoui, A., Walther, C., Synal, & Christl, M. (2016). First 236U data from the Arctic Ocean and use of 236U/238U and 129I/236U as a new dual tracer. Earth and Planetary Science Letters, 440, Charette, , Lam, , Lohan, , Kwon, , Hatje. V., Jeandel, C., Shiller, , Cutter, , Thomas, A., Boyd, , Homoky, , Milne, A., Andersson, , Porcelli, D., Geibert, W. & Orellana, (2016). Coastal ocean and shelf-sea biogeochemical cycling of trace elements and isotopes: lessons learnt from GEOTRACES . Phil. Trans. R. Soc. A, 374 (2081), German, , Casciotti, , Dutay, , Heimb rger, , Jenkins, , Measures, , Mills, , Obata, H., Schlitzer, R., Tagliabue, A.

7 , Turner, , Whitby, H. (2016). Hydrothermal impacts on trace element and isotope ocean biogeochemistry. Phil. Trans. R. Soc. A., 374, (2081), doi:1098 Henderson, G M. (2016). Ocean Trace Element Cycles. Phil. Trans. R. Soc. A, 374 (2081), Homoky, (2017). Biogeochemistry: Deep ocean iron balance. Nature Geoscience, 10, 162-163, doi:1038/ngeo2908. Homoky, , Weber, , Berelson, , Conway, , Henderson, , van Hulten, M., Jeandel, C., Severmann, S. & Tagliabue, A. (2016). Quantifying Trace Element and Isotope Fluxes at the Ocean-sediment Boundary: A Review. Phil. Trans. R. Soc. A, 374 (2081), Jickells, , Buitenhuis, , Altieri, K., Baker, , Capone, D., Duce, , Dentener, F., Fennel, K., Kanakidou, M., LaRoche, J., Lee, K., Liss, , Middelburg, J J.

8 , Moore, , Okin, G., Oschlies, A., Sarin, M., Seitzinger, S., Sharples, J, Singh, A., Suntharalingam, P., Uematsu, M. & Zamora, (2017). A re-evaluation of the magnitude and impacts of anthropogenic atmospheric nitrogen inputs on the ocean. Global Biogeochemical Cycles, 31, Klar, , Homoky, , Statham, , Birchill, , Harris, , Woodward, , Silburn, B., Cooper, , James, , Connelly, , Chever, F., Lichtschlag, A. & Graves, C. (2017). Stability of dissolved and soluble Fe(II) in shelf sediment pore waters and release to an oxic water column. Biogeochemistry, 1-19, Lough, , Klar, , Homoky, , Comer-Warner, , Milton, , Connelly, , James, & Mills, (2017). Opposing authigenic controls on the isotopic signature of dissolved iron in hydrothermal plumes.

9 Geochimica et Cosmochimica Acta, 202, 1-20, Milne, , Schlosser, C., Wake, B., Achterberg, , Chance, R., Baker, A., Forryan, A. & Lohan, (2017). Particulate phases are key in controlling dissolved iron concentrations in the (sub)tropical North Atlantic. Geophysical Research Letters, 44, Moore, (2016). Diagnosing oceanic nutrient deficiency. Phil. Trans. R. Soc. A, 374 (2081), doi:1098 Myriokefalitakis, S., Nenes, A., Baker, , Mihalopoulos, N. & Kanakidou, M. (2016). Bioavailable atmospheric phosphorous supply to the global ocean: a 3-D global modelling study. Biogeosciences, 13, 6519-6543, Osborne , Hathorne, , Schijf, J., Plancherel, Y., Boening, P. & Frank M. (2017). The potential of sedimentary foraminiferal rare earth element patterns to trace water masses in the , Geophysics, Geosystems, Shelley, , Wyatt, , Tarran, , Rees, , Worsfold, & Lohan, (2016).

10 A tale of two gyres: Contrasting distributions of dissolved cobalt and iron in the Atlantic Ocean. Progress in Oceanography, Tachikawa K., Arsouze, T. Bayon, G., Bory, A., Colin, C. Dutay, , Frank, N., Giraud, X., Gourlan,T., Jeandel, C., Lacan, F., Meynardier, , Montagna, P., Piotrowski, A., Plancherel, Y., Puceat, E., Roy-Barman, M. & Waelbroeck, C. (2017). The large-scale evolution of neodymium isotopic composition in the global modern and Holocene ocean revealed from seawater and archive data. Chemical Geology, Tagliabue, A. & Resing, J. (2016). Impact of hydrothermalism on the ocean iron cycle. Phil. Trans. R. Soc. A, 374 (2081), doi:1098 Tagliabue, A., Bowie, , Boyd, , Buck, , Johnson, & Saito, (2017). The integral role of iron in ocean biogeochemistry, Nature, Vance, D.