Ohnemus
Daniel C.
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Daniel C.
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PreprintIntensity of Th and Pa scavenging partitioned by particle chemistry in the North Atlantic Ocean( 2015-01) Hayes, Christopher T. ; Anderson, Robert F. ; Fleisher, Martin Q. ; Vivancos, Sebastian M. ; Lam, Phoebe J. ; Ohnemus, Daniel C. ; Huang, Kuo-Fang ; Robinson, Laura F. ; Lu, Yanbin ; Cheng, Hai ; Edwards, R. Lawrence ; Moran, S. BradleyThe natural radionuclides 231Pa and 230Th are incorporated into the marine sediment record by scavenging, or adsorption to various particle types, via chemical reactions that are not fully understood. Because these isotopes have potential value in tracing several oceanographic processes, we investigate the nature of scavenging using trans-Atlantic measurements of dissolved (<0.45 μm) and particulate (0.8-51 μm) 231Pa and 230Th, together with major particle composition. We find widespread impact of intense scavenging by authigenic Fe/Mn (hydr)oxides, in the form of hydrothermal particles emanating from the Mid-Atlantic ridge and particles resuspended from reducing conditions near the seafloor off the coast of West Africa. Biogenic opal was not found to be a significant scavenging phase for either element in this sample set, essentially because of its low abundance and small dynamic range at the studied sites. Distribution coefficients in shallow (< 200 m) depths are anomalously low which suggests either the unexpected result of a low scavenging intensity for organic matter or that, in water masses containing abundant organic-rich particles, a greater percentage of radionuclides exist in the colloidal or complexed phase. In addition to particle concentration, the oceanic distribution of particle types likely plays a significant role in the ultimate distribution of sedimentary 230Th and 231Pa.
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ArticleThe GEOTRACES Intermediate Data Product 2014(Elsevier, 2015-04-16) Mawji, Edward ; Schlitzer, Reiner ; Dodas, Elena Masferrer ; Abadie, Cyril ; Abouchami, Wafa ; Anderson, Robert F. ; Baars, Oliver ; Bakker, Karel ; Baskaran, Mark ; Bates, Nicholas R. ; Bluhm, Katrin ; Bowie, Andrew R. ; Bown, Johann ; Boye, Marie ; Marie, Edward A. ; Branellec, Pierre ; Bruland, Kenneth W. ; Brzezinski, Mark A. ; Bucciarelli, Eva ; Buesseler, Ken O. ; Butler, Edward ; Cai, Pinghe ; Cardinal, Damien ; Casciotti, Karen L. ; Chaves, Joaquin E. ; Cheng, Hai ; Chever, Fanny ; Church, Thomas M. ; Colman, Albert S. ; Conway, Tim M. ; Croot, Peter L. ; Cutter, Gregory A. ; Baar, Hein J. W. de ; de Souza, Gregory F. ; Dehairs, Frank ; Deng, Feifei ; Dieu, Huong Thi ; Dulaquais, Gabriel ; Echegoyen-Sanz, Yolanda ; Edwards, R. Lawrence ; Fahrbach, Eberhard ; Fitzsimmons, Jessica N. ; Fleisher, Martin Q. ; Frank, Martin ; Friedrich, Jana ; Fripiat, Francois ; Galer, Stephen J. G. ; Gamo, Toshitaka ; Garcia Solsona, Ester ; Gerringa, Loes J. A. ; Godoy, Jose Marcus ; Gonzalez, Santiago ; Grossteffan, Emilie ; Hatta, Mariko ; Hayes, Christopher T. ; Heller, Maija Iris ; Henderson, Gideon M. ; Huang, Kuo-Fang ; Jeandel, Catherine ; Jenkins, William J. ; John, Seth G. ; Kenna, Timothy C. ; Klunder, Maarten ; Kretschmer, Sven ; Kumamoto, Yuichiro ; Laan, Patrick ; Labatut, Marie ; Lacan, Francois ; Lam, Phoebe J. ; Lannuzel, Delphine ; le Moigne, Frederique ; Lechtenfeld, Oliver J. ; Lohan, Maeve C. ; Lu, Yanbin ; Masqué, Pere ; McClain, Charles R. ; Measures, Christopher I. ; Middag, Rob ; Moffett, James W. ; Navidad, Alicia ; Nishioka, Jun ; Noble, Abigail E. ; Obata, Hajime ; Ohnemus, Daniel C. ; Owens, Stephanie A. ; Planchon, Frederic ; Pradoux, Catherine ; Puigcorbe, Viena ; Quay, Paul D. ; Radic, Amandine ; Rehkamper, Mark ; Remenyi, Tomas A. ; Rijkenberg, Micha J. A. ; Rintoul, Stephen R. ; Robinson, Laura F. ; Roeske, Tobias ; Rosenberg, Mark ; Rutgers van der Loeff, Michiel M. ; Ryabenko, Evgenia ; Saito, Mak A. ; Roshan, Saeed ; Salt, Lesley ; Sarthou, Geraldine ; Schauer, Ursula ; Scott, Peter M. ; Sedwick, Peter N. ; Sha, Lijuan ; Shiller, Alan M. ; Sigman, Daniel M. ; Smethie, William M. ; Smith, Geoffrey J. ; Sohrin, Yoshiki ; Speich, Sabrina ; Stichel, Torben ; Stutsman, Johnny ; Swift, James H. ; Tagliabue, Alessandro ; Thomas, Alexander L. ; Tsunogai, Urumu ; Twining, Benjamin S. ; van Aken, Hendrik M. ; van Heuven, Steven ; van Ooijen, Jan ; van Weerlee, Evaline ; Venchiarutti, Celia ; Voelker, Antje H. L. ; Wake, Bronwyn ; Warner, Mark J. ; Woodward, E. Malcolm S. ; Wu, Jingfeng ; Wyatt, Neil ; Yoshikawa, Hisayuki ; Zheng, Xin-Yuan ; Xue, Zichen ; Zieringer, Moritz ; Zimmer, Louise A.The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEIs) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in the IDP2014 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at cross-over stations. The digital data are provided in several formats, including ASCII spreadsheet, Excel spreadsheet, netCDF, and Ocean Data View collection. In addition to the actual data values the IDP2014 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering. Metadata about data originators, analytical methods and original publications related to the data are linked to the data in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2014 data providing section plots and a new kind of animated 3D scenes. The basin-wide 3D scenes allow for viewing of data from many cruises at the same time, thereby providing quick overviews of large-scale tracer distributions. In addition, the 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of observed tracer plumes, as well as for making inferences about controlling processes.
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ArticleFlux of particulate elements in the North Atlantic Ocean constrained by multiple radionuclides(American Geophysical Union, 2018-11-22) Hayes, Christopher T. ; Black, Erin E. ; Anderson, Robert F. ; Baskaran, Mark ; Buesseler, Ken O. ; Charette, Matthew A. ; Cheng, Hai ; Cochran, J. Kirk ; Edwards, R. Lawrence ; Fitzgerald, Patrick ; Lam, Phoebe J. ; Lu, Yanbin ; Morris, Stephanie O. ; Ohnemus, Daniel C. ; Pavia, Frank ; Stewart, Gillian ; Tang, YiSinking particles strongly regulate the distribution of reactive chemical substances in the ocean, including particulate organic carbon and other elements (e.g., P, Cd, Mn, Cu, Co, Fe, Al, and 232Th). Yet, the sinking fluxes of trace elements have not been well described in the global ocean. The U.S. GEOTRACES campaign in the North Atlantic (GA03) offers the first data set in which the sinking flux of carbon and trace elements can be derived using four different radionuclide pairs (238U:234Th ;210Pb:210Po; 228Ra:228Th; and 234U:230Th) at stations co‐located with sediment trap fluxes for comparison. Particulate organic carbon, particulate P, and particulate Cd fluxes all decrease sharply with depth below the euphotic zone. Particulate Mn, Cu, and Co flux profiles display mixed behavior, some cases reflecting biotic remineralization, and other cases showing increased flux with depth. The latter may be related to either lateral input of lithogenic material or increased scavenging onto particles. Lastly, particulate Fe fluxes resemble fluxes of Al and 232Th, which all have increasing flux with depth, indicating a dominance of lithogenic flux at depth by resuspended sediment transported laterally to the study site. In comparing flux estimates derived using different isotope pairs, differences result from different timescales of integration and particle size fractionation effects. The range in flux estimates produced by different methods provides a robust constraint on the true removal fluxes, taking into consideration the independent uncertainties associated with each method. These estimates will be valuable targets for biogeochemical modeling and may also offer insight into particle sinking processes.
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ArticleDissolved and particulate barium distributions along the US GEOTRACES North Atlantic and East Pacific zonal transects (GA03 and GP16): global implications for the marine barium cycle(American Geophysical Union, 2022-05-23) Rahman, Shaily ; Shiller, Alan M. ; Anderson, Robert F. ; Charette, Matthew A. ; Hayes, Christopher T. ; Gilbert, Melissa ; Grissom, Karen ; Lam, Phoebe J. ; Ohnemus, Daniel C. ; Pavia, Frank ; Twining, Benjamin S. ; Vivancos, Sebastian M.Processes controlling dissolved barium (dBa) were investigated along the GEOTRACES GA03 North Atlantic and GP16 Eastern Tropical Pacific transects, which traversed similar physical and biogeochemical provinces. Dissolved Ba concentrations are lowest in surface waters (∼35–50 nmol kg−1) and increase to 70–80 and 140–150 nmol kg−1 in deep waters of the Atlantic and Pacific transects, respectively. Using water mass mixing models, we estimate conservative mixing that accounts for most of dBa variability in both transects. To examine nonconservative processes, particulate excess Ba (pBaxs) formation and dissolution rates were tracked by normalizing particulate excess 230Th activities. Th-normalized pBaxs fluxes, with barite as the likely phase, have subsurface maxima in the top 1,000 m (∼100–200 μmol m−2 year−1 average) in both basins. Barite precipitation depletes dBa within oxygen minimum zones from concentrations predicted by water mass mixing, whereas inputs from continental margins, particle dissolution in the water column, and benthic diffusive flux raise dBa above predications. Average pBaxs burial efficiencies along GA03 and GP16 are ∼37% and 17%–100%, respectively, and do not seem to be predicated on barite saturation indices in the overlying water column. Using published values, we reevaluate the global freshwater dBa river input as 6.6 ± 3.9 Gmol year−1. Estuarine mixing processes may add another 3–13 Gmol year−1. Dissolved Ba inputs from broad shallow continental margins, previously unaccounted for in global marine summaries, are substantial (∼17 Gmol year−1), exceeding terrestrial freshwater inputs. Revising river and shelf dBa inputs may help bring the marine Ba isotope budget more into balance.
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ArticleThe GEOTRACES Intermediate Data Product 2017(Elsevier, 2018-06-01) Schlitzer, Reiner ; Anderson, Robert F. ; Dodas, Elena Masferrer ; Lohan, Maeve C. ; Geibert, Walter ; Tagliabue, Alessandro ; Bowie, Andrew R. ; Jeandel, Catherine ; Maldonado, Maria T. ; Landing, William M. ; Cockwell, Donna ; Abadie, Cyril ; Abouchami, Wafa ; Achterberg, Eric P. ; Agather, Alison ; Aguliar-Islas, Ana ; van Aken, Hendrik M. ; Andersen, Morten ; Archer, Corey ; Auro, Maureen E. ; Baar, Hein J. W. de ; Baars, Oliver ; Baker, Alex R. ; Bakker, Karel ; Basak, Chandranath ; Baskaran, Mark ; Bates, Nicholas R. ; Bauch, Dorothea ; van Beek, Pieter ; Behrens, Melanie K. ; Black, Erin E. ; Bluhm, Katrin ; Bopp, Laurent ; Bouman, Heather ; Bowman, Katlin ; Bown, Johann ; Boyd, Philip ; Boye, Marie ; Boyle, Edward A. ; Branellec, Pierre ; Bridgestock, Luke ; Brissebrat, Guillaume ; Browning, Thomas ; Bruland, Kenneth W. ; Brumsack, Hans-Jürgen ; Brzezinski, Mark A. ; Buck, Clifton S. ; Buck, Kristen N. ; Buesseler, Ken O. ; Bull, Abby ; Butler, Edward ; Cai, Pinghe ; Cámara Mor, Patricia ; Cardinal, Damien ; Carlson, Craig ; Carrasco, Gonzalo ; Casacuberta, Nuria ; Casciotti, Karen L. ; Castrillejo, Maxi ; Chamizo, Elena ; Chance, Rosie ; Charette, Matthew A. ; Chaves, Joaquin E. ; Cheng, Hai ; Chever, Fanny ; Christl, Marcus ; Church, Thomas M. ; Closset, Ivia ; Colman, Albert S. ; Conway, Tim M. ; Cossa, Daniel ; Croot, Peter L. ; Cullen, Jay T. ; Cutter, Gregory A. ; Daniels, Chris ; Dehairs, Frank ; Deng, Feifei ; Dieu, Huong Thi ; Duggan, Brian ; Dulaquais, Gabriel ; Dumousseaud, Cynthia ; Echegoyen-Sanz, Yolanda ; Edwards, R. Lawrence ; Ellwood, Michael J. ; Fahrbach, Eberhard ; Fitzsimmons, Jessica N. ; Flegal, A. Russell ; Fleisher, Martin Q. ; van de Flierdt, Tina ; Frank, Martin ; Friedrich, Jana ; Fripiat, Francois ; Fröllje, Henning ; Galer, Stephen J. G. ; Gamo, Toshitaka ; Ganeshram, Raja S. ; Garcia-Orellana, Jordi ; Garcia Solsona, Ester ; Gault-Ringold, Melanie ; George, Ejin ; Gerringa, Loes J. A. ; Gilbert, Melissa ; Godoy, Jose Marcus ; Goldstein, Steven L. ; Gonzalez, Santiago ; Grissom, Karen ; Hammerschmidt, Chad R. ; Hartman, Alison ; Hassler, Christel ; Hathorne, Ed C. ; Hatta, Mariko ; Hawco, Nicholas J. ; Hayes, Christopher T. ; Heimbürger, Lars-Eric ; Helgoe, Josh ; Heller, Maija Iris ; Henderson, Gideon M. ; Henderson, Paul B. ; van Heuven, Steven ; Ho, Peng ; Horner, Tristan J. ; Hsieh, Yu-Te ; Huang, Kuo-Fang ; Humphreys, Matthew P. ; Isshiki, Kenji ; Jacquot, Jeremy E. ; Janssen, David J. ; Jenkins, William J. ; John, Seth ; Jones, Elizabeth M. ; Jones, Janice L. ; Kadko, David ; Kayser, Rick ; Kenna, Timothy C. ; Khondoker, Roulin ; Kim, Taejin ; Kipp, Lauren ; Klar, Jessica K. ; Klunder, Maarten ; Kretschmer, Sven ; Kumamoto, Yuichiro ; Laan, Patrick ; Labatut, Marie ; Lacan, Francois ; Lam, Phoebe J. ; Lambelet, Myriam ; Lamborg, Carl H. ; le Moigne, Frederique ; Le Roy, Emilie ; Lechtenfeld, Oliver J. ; Lee, Jong-Mi ; Lherminier, Pascale ; Little, Susan ; López-Lora, Mercedes ; Lu, Yanbin ; Masque, Pere ; Mawji, Edward ; McClain, Charles R. ; Measures, Christopher I. ; Mehic, Sanjin ; Menzel Barraqueta, Jan-Lukas ; Merwe, Pier van der ; Middag, Rob ; Mieruch, Sebastian ; Milne, Angela ; Minami, Tomoharu ; Moffett, James W. ; Moncoiffe, Gwenaelle ; Moore, Willard S. ; Morris, Paul J. ; Morton, Peter L. ; Nakaguchi, Yuzuru ; Nakayama, Noriko ; Niedermiller, John ; Nishioka, Jun ; Nishiuchi, Akira ; Noble, Abigail E. ; Obata, Hajime ; Ober, Sven ; Ohnemus, Daniel C. ; van Ooijen, Jan ; O'Sullivan, Jeanette ; Owens, Stephanie A. ; Pahnke, Katharina ; Paul, Maxence ; Pavia, Frank ; Pena, Leopoldo D. ; Peters, Brian ; Planchon, Frederic ; Planquette, Helene ; Pradoux, Catherine ; Puigcorbé, Viena ; Quay, Paul D. ; Queroue, Fabien ; Radic, Amandine ; Rauschenberg, Sara ; Rehkämper, Mark ; Rember, Robert ; Remenyi, Tomas A. ; Resing, Joseph A. ; Rickli, Joerg ; Rigaud, Sylvain ; Rijkenberg, Micha J. A. ; Rintoul, Stephen R. ; Robinson, Laura F. ; Roca-Martí, Montserrat ; Rodellas, Valenti ; Roeske, Tobias ; Rolison, John M. ; Rosenberg, Mark ; Roshan, Saeed ; Rutgers van der Loeff, Michiel M. ; Ryabenko, Evgenia ; Saito, Mak A. ; Salt, Lesley ; Sanial, Virginie ; Sarthou, Geraldine ; Schallenberg, Christina ; Schauer, Ursula ; Scher, Howie ; Schlosser, Christian ; Schnetger, Bernhard ; Scott, Peter M. ; Sedwick, Peter N. ; Semiletov, Igor P. ; Shelley, Rachel U. ; Sherrell, Robert M. ; Shiller, Alan M. ; Sigman, Daniel M. ; Singh, Sunil Kumar ; Slagter, Hans ; Slater, Emma ; Smethie, William M. ; Snaith, Helen ; Sohrin, Yoshiki ; Sohst, Bettina M. ; Sonke, Jeroen E. ; Speich, Sabrina ; Steinfeldt, Reiner ; Stewart, Gillian ; Stichel, Torben ; Stirling, Claudine H. ; Stutsman, Johnny ; Swarr, Gretchen J. ; Swift, James H. ; Thomas, Alexander ; Thorne, Kay ; Till, Claire P. ; Till, Ralph ; Townsend, Ashley T. ; Townsend, Emily ; Tuerena, Robyn ; Twining, Benjamin S. ; Vance, Derek ; Velazquez, Sue ; Venchiarutti, Celia ; Villa-Alfageme, Maria ; Vivancos, Sebastian M. ; Voelker, Antje H. L. ; Wake, Bronwyn ; Warner, Mark J. ; Watson, Ros ; van Weerlee, Evaline ; Weigand, M. Alexandra ; Weinstein, Yishai ; Weiss, Dominik ; Wisotzki, Andreas ; Woodward, E. Malcolm S. ; Wu, Jingfeng ; Wu, Yingzhe ; Wuttig, Kathrin ; Wyatt, Neil ; Xiang, Yang ; Xie, Ruifang C. ; Xue, Zichen ; Yoshikawa, Hisayuki ; Zhang, Jing ; Zhang, Pu ; Zhao, Ye ; Zheng, Linjie ; Zheng, Xin-Yuan ; Zieringer, Moritz ; Zimmer, Louise A. ; Ziveri, Patrizia ; Zunino, Patricia ; Zurbrick, CherylThe GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the previous IDP2014. For the first time, the IDP2017 contains data for a large suite of biogeochemical parameters as well as aerosol and rain data characterising atmospheric trace element and isotope (TEI) sources. The TEI data in the IDP2017 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at crossover stations. The IDP2017 consists of two parts: (1) a compilation of digital data for more than 450 TEIs as well as standard hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing an on-line atlas that includes more than 590 section plots and 130 animated 3D scenes. The digital data are provided in several formats, including ASCII, Excel spreadsheet, netCDF, and Ocean Data View collection. Users can download the full data packages or make their own custom selections with a new on-line data extraction service. In addition to the actual data values, the IDP2017 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering and for statistical analysis. Metadata about data originators, analytical methods and original publications related to the data are linked in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2017 as section plots and rotating 3D scenes. The basin-wide 3D scenes combine data from many cruises and provide quick overviews of large-scale tracer distributions. These 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of tracer plumes near ocean margins or along ridges. The IDP2017 is the result of a truly international effort involving 326 researchers from 25 countries. This publication provides the critical reference for unpublished data, as well as for studies that make use of a large cross-section of data from the IDP2017. This article is part of a special issue entitled: Conway GEOTRACES - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González.