Cullen
Jay T.
Cullen
Jay T.
No Thumbnail Available
Search Results
Now showing
1 - 4 of 4
-
ArticleElevated sources of cobalt in the Arctic Ocean(European Geosciences Union, 2020-10-01) Bundy, Randelle M. ; Tagliabue, Alessandro ; Hawco, Nicholas J. ; Morton, Peter L. ; Twining, Benjamin S. ; Hatta, Mariko ; Noble, Abigail E. ; Cape, Mattias R. ; John, Seth G. ; Cullen, Jay T. ; Saito, Mak A.Cobalt (Co) is an important bioactive trace metal that is the metal cofactor in cobalamin (vitamin B12) which can limit or co-limit phytoplankton growth in many regions of the ocean. Total dissolved and labile Co measurements in the Canadian sector of the Arctic Ocean during the U.S. GEOTRACES Arctic expedition (GN01) and the Canadian International Polar Year GEOTRACES expedition (GIPY14) revealed a dynamic biogeochemical cycle for Co in this basin. The major sources of Co in the Arctic were from shelf regions and rivers, with only minimal contributions from other freshwater sources (sea ice, snow) and eolian deposition. The most striking feature was the extremely high concentrations of dissolved Co in the upper 100 m, with concentrations routinely exceeding 800 pmol L−1 over the shelf regions. This plume of high Co persisted throughout the Arctic basin and extended to the North Pole, where sources of Co shifted from primarily shelf-derived to riverine, as freshwater from Arctic rivers was entrained in the Transpolar Drift. Dissolved Co was also strongly organically complexed in the Arctic, ranging from 70 % to 100 % complexed in the surface and deep ocean, respectively. Deep-water concentrations of dissolved Co were remarkably consistent throughout the basin (∼55 pmol L−1), with concentrations reflecting those of deep Atlantic water and deep-ocean scavenging of dissolved Co. A biogeochemical model of Co cycling was used to support the hypothesis that the majority of the high surface Co in the Arctic was emanating from the shelf. The model showed that the high concentrations of Co observed were due to the large shelf area of the Arctic, as well as to dampened scavenging of Co by manganese-oxidizing (Mn-oxidizing) bacteria due to the lower temperatures. The majority of this scavenging appears to have occurred in the upper 200 m, with minimal additional scavenging below this depth. Evidence suggests that both dissolved Co (dCo) and labile Co (LCo) are increasing over time on the Arctic shelf, and these limited temporal results are consistent with other tracers in the Arctic. These elevated surface concentrations of Co likely lead to a net flux of Co out of the Arctic, with implications for downstream biological uptake of Co in the North Atlantic and elevated Co in North Atlantic Deep Water. Understanding the current distributions of Co in the Arctic will be important for constraining changes to Co inputs resulting from regional intensification of freshwater fluxes from ice and permafrost melt in response to ongoing climate change.
-
Working PaperPaths forward for exploring ocean iron fertilization(Woods Hole Oceanographic Institution, 2023-10-26) Buesseler, Kenneth O. ; Bianchi, Daniele ; Chai, Fei ; Cullen, Jay T. ; Estapa, Margaret L. ; Hawco, Nicholas J. ; John, Seth G. ; McGillicuddy, Dennis J. ; Nawaz, Sara ; Ramakrishna, Kilaparti ; Siegel, David A. ; Smith, Sarah R. ; Steinberg, Deborah K. ; Turk-Kubo, Kendra A. ; Twining, Benjamin S. ; Webb, Romany ; Wells, Mark L. ; White, Angelicque E. ; Yoon, Joo-EunWe need a new way of talking about global warming. UN Secretary General António Guterres underscored this when he said the “era of global boiling” has arrived. Although we have made remarkable progress on a very complex problem over the past thirty years, we have a long way to go before we can keep the global temperature increase to below 2°C relative to the pre-industrial times. Climate models suggest that this next decade is critical if we are to avert the worst consequences of climate change. The world must continue to reduce greenhouse gas emissions, and find ways to adapt and build resilience among vulnerable communities. At the same time, we need to find new ways to remove carbon dioxide from the atmosphere in order to chart a “net negative” emissions pathway. Given their large capacity for carbon storage, the oceans must be included in consideration of our multiple carbon dioxide removal (CDR) options. This report focused on ocean iron fertilization (OIF) for marine CDR. This is by no means a new scientific endeavor. Several members of ExOIS (Exploring Ocean Iron Solutions) have been studying this issue for decades, but the emergence of runaway climate impacts has motivated this group to consider a responsible path forward for marine CDR. That path needs to ensure that future choices are based upon the best science and social considerations required to reduce human suffering and counter economic and ecological losses, while limiting and even reversing the negative impacts that climate change is already having on the ocean and the rest of the planet. Prior studies have confirmed that the addition of small amounts of iron in some parts of the ocean is effective at stimulating phytoplankton growth. Through enhanced photosynthesis, carbon dioxide can not only be removed from the atmosphere but a fraction can also be transferred to durable storage in the deep sea. However, prior studies were not designed to quantify how effective this storage can be, or how wise OIF might be as a marine CDR approach. ExOIS is a consortium that was created in 2022 to consider what OIF studies are needed to answer critical questions about the potential efficiency and ecological impacts of marine CDR (http://oceaniron.org). Owing to concerns surrounding the ethics of marine CDR, ExOIS is organized around a responsible code of conduct that prioritizes activities for the collective benefit of our planet with an emphasis on open and transparent studies that include public engagement. Our goal is to establish open-source conventions for implementing OIF for marine CDR that can be assessed with appropriate monitoring, reporting, and verification (MRV) protocols, going beyond just carbon accounting, to assess ecological and other non-carbon environmental effects (eMRV). As urgent as this is, it will still take 5 to 10 years of intensive work and considerable resources to accomplish this goal. We present here a “Paths Forward’’ report that stems from a week-long workshop held at the Moss Landing Marine Laboratories in May 2023 that was attended by international experts spanning atmospheric, oceanographic, and social sciences as well as legal specialists (see inside back cover). At the workshop, we reviewed prior OIF studies, distilled the lessons learned, and proposed several paths forward over the next decade to lay the foundation for evaluating OIF for marine CDR. Our discussion very quickly resulted in a recommendation for the need to establish multiple “Ocean Iron Observatories’’ where, through observations and modeling, we would be able to assess with a high degree of certainty both the durable removal of atmospheric carbon dioxide—which we term the “centennial tonne”—and the ecological response of the ocean. In a five-year phase I period, we prioritize five major research activities: 1. Next generation field studies: Studies of long-term (durable) carbon storage will need to be longer (year or more) and larger (>10,000 km2) than past experiments, organized around existing tools and models, but with greater reliance on autonomous platforms. While prior studies suggested that ocean systems return to ambient conditions once iron infusion is stopped, this needs to be verified. We suggest that these next field experiments take place in the NE Pacific to assess the processes controlling carbon removal efficiencies, as well as the intended and unintended ecological and geochemical consequences. 2. Regional, global and field study modeling Incorporation of new observations and model intercomparisons are essential to accurately represent how iron cycling processes regulate OIF effects on marine ecosystems and carbon sequestration, to support experimental planning for large-scale MRV, and to guide decision making on marine CDR choices. 3. New forms of iron and delivery mechanisms Rigorous testing and comparison of new forms of iron and their potential delivery mechanisms is needed to optimize phytoplankton growth while minimizing the financial and carbon costs of OIF. Efficiency gains are expected to generate responses closer to those of natural OIF events. 4. Monitoring, reporting, and verification: Advances in observational technologies and platforms are needed to support the development, validation, and maintenance of models required for MRV of large-scale OIF deployment. In addition to tracking carbon storage and efficiency, prioritizing eMRV will be key to developing regulated carbon markets. 5. Governance and stakeholder engagement: Attention to social dimensions, governance, and stakeholder perceptions will be essential from the start, with particular emphasis on expanding the diversity of groups engaged in marine CDR across the globe. This feedback will be a critical component underlying future decisions about whether to proceed, or not, with OIF for marine CDR. Paramount in the plan is the need to move carefully. Our goal is to conduct these five activities in parallel to inform decisions steering the establishment of ocean iron observatories at multiple locations in phase II. When completed, this decadal plan will provide a rich knowledge base to guide decisions about if, when, where, and under what conditions OIF might be responsibly implemented for marine CDR. The consensus of our workshop and this report is that now is the time for actionable studies to begin. Quite simply, we suggest that some form of marine CDR will be essential to slow down and reverse the most severe consequences of our disrupted climate. OIF has the potential to be one of these climate mitigation strategies. We have the opportunity and obligation to invest in the knowledge necessary to ensure that we can make scientifically and ethically sound decisions for the future of our planet.
-
ArticleNitrous oxide distributions in the oxygenated water column of the Sargasso Sea(Taylor and Francis Group, 2022-12-15) Meyer, Annaliese C. S. ; Cullen, Jay T. ; Grundle, Damian S.This study presents dissolved nitrous oxide (N2O) concentrations in the water column at the Bermuda Atlantic Time-series Study (BATS) station and uses a subset of these measurements to estimate air-to-sea flux for four specific time points between September 2018 and June 2019. N2O concentrations at BATS were in the range of 4.0 nmol L−1-16.9 nmol L−1, with vertical profiles which were the mirror inverse of dissolved oxygen. Regardless of season, N2O concentration maxima were found within the oxygen minimum zone (OMZ). The highest maximum N2O values were observed in November and lowest in October. As the water column at BATS remains consistently at dissolved oxygen concentrations greater than 140 µmol L−1, and therefore aerobic, we assume that the bulk of N2O production occurs through nitrification. A nitrification source is supported by a correlation between excess N2O (ΔN2O) below the mixed layer, apparent oxygen utilization (AOU) and nitrate concentrations. We estimate a pooled average yield of 0.027% to 0.038% N2O from nitrification at BATS. Finally, estimates of air-sea exchange of N2O using regional average monthly wind speeds indicated that this region acts as a weak source or a sink of atmospheric N2O, and varies between months.
-
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 A. ; 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.