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ArticleCarbon cycling in the North American coastal ocean: a synthesis(European Geosciences Union, 2019-03-27) Fennel, Katja ; Alin, Simone R. ; Barbero, Leticia ; Evans, Wiley ; Bourgeois, Timothée ; Cooley, Sarah R. ; Dunne, John P. ; Feely, Richard A. ; Hernandez-Ayon, Jose Martin ; Hu, Xinping ; Lohrenz, Steven E. ; Muller-Karger, Frank E. ; Najjar, Raymond G. ; Robbins, Lisa ; Shadwick, Elizabeth H. ; Siedlecki, Samantha A. ; Steiner, Nadja ; Sutton, Adrienne J. ; Turk, Daniela ; Vlahos, Penny ; Wang, Zhaohui AleckA quantification of carbon fluxes in the coastal ocean and across its boundaries with the atmosphere, land, and the open ocean is important for assessing the current state and projecting future trends in ocean carbon uptake and coastal ocean acidification, but this is currently a missing component of global carbon budgeting. This synthesis reviews recent progress in characterizing these carbon fluxes for the North American coastal ocean. Several observing networks and high-resolution regional models are now available. Recent efforts have focused primarily on quantifying the net air–sea exchange of carbon dioxide (CO2). Some studies have estimated other key fluxes, such as the exchange of organic and inorganic carbon between shelves and the open ocean. Available estimates of air–sea CO2 flux, informed by more than a decade of observations, indicate that the North American Exclusive Economic Zone (EEZ) acts as a sink of 160±80 Tg C yr−1, although this flux is not well constrained. The Arctic and sub-Arctic, mid-latitude Atlantic, and mid-latitude Pacific portions of the EEZ account for 104, 62, and −3.7 Tg C yr−1, respectively, while making up 51 %, 25 %, and 24 % of the total area, respectively. Combining the net uptake of 160±80 Tg C yr−1 with an estimated carbon input from land of 106±30 Tg C yr−1 minus an estimated burial of 65±55 Tg C yr−1 and an estimated accumulation of dissolved carbon in EEZ waters of 50±25 Tg C yr−1 implies a carbon export of 151±105 Tg C yr−1 to the open ocean. The increasing concentration of inorganic carbon in coastal and open-ocean waters leads to ocean acidification. As a result, conditions favoring the dissolution of calcium carbonate occur regularly in subsurface coastal waters in the Arctic, which are naturally prone to low pH, and the North Pacific, where upwelling of deep, carbon-rich waters has intensified. Expanded monitoring and extension of existing model capabilities are required to provide more reliable coastal carbon budgets, projections of future states of the coastal ocean, and quantification of anthropogenic carbon contributions.
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ArticleImpact of seabed resuspension on oxygen and nitrogen dynamics in the northern Gulf of Mexico : a numerical modeling study(John Wiley & Sons, 2018-10-15) Moriarty, Julia M. ; Harris, Courtney K. ; Friedrichs, Marjorie A. M. ; Fennel, Katja ; Xu, KehuiResuspension affects water quality in coastal environments by entraining seabed organic matter into the water column, which can increase remineralization, alter seabed fluxes, decrease water clarity, and affect oxygen and nutrient dynamics. Nearly all numerical models of water column biogeochemistry, however, simplify seabed and bottom boundary layer processes and neglect resuspension. Here we implemented HydroBioSed, a coupled hydrodynamic‐sediment transport‐biogeochemical model to examine the role of resuspension in regulating oxygen and nitrogen dynamics on timescales of a day to a month. The model was implemented for the northern Gulf of Mexico, where the extent of summertime hypoxia is sensitive to seabed and bottom boundary layer processes. Results indicated that particulate organic matter remineralization in the bottom water column increased by an order of magnitude during resuspension events. This increased sediment oxygen consumption and ammonium production, which were defined as the sum of seabed fluxes of oxygen and ammonium, plus oxygen consumption and ammonium production in the water column due to resuspended organic matter. The increases in remineralization impacted biogeochemical dynamics to a greater extent than resuspension‐induced seabed fluxes and oxidation of reduced chemical species. The effect of resuspension on bottom water biogeochemistry increased with particulate organic matter availability, which was modulated by sediment transport patterns. Overall, when averaged over the shelf and on timescales of a month in the numerical model, cycles of erosion and deposition accounted for about two thirds of sediment oxygen consumption and almost all of the sediment ammonium production.
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ArticleOn the future of Argo: A global, full-depth, multi-disciplinary array(Frontiers Media, 2019-08-02) Roemmich, Dean ; Alford, Matthew H. ; Claustre, Hervé ; Johnson, Kenneth S. ; King, Brian ; Moum, James N. ; Oke, Peter ; Owens, W. Brechner ; Pouliquen, Sylvie ; Purkey, Sarah G. ; Scanderbeg, Megan ; Suga, Koushirou ; Wijffels, Susan E. ; Zilberman, Nathalie ; Bakker, Dorothee ; Baringer, Molly O. ; Belbeoch, Mathieu ; Bittig, Henry C. ; Boss, Emmanuel S. ; Calil, Paulo H. R. ; Carse, Fiona ; Carval, Thierry ; Chai, Fei ; Conchubhair, Diarmuid Ó. ; d’Ortenzio, Fabrizio ; Dall'Olmo, Giorgio ; Desbruyeres, Damien ; Fennel, Katja ; Fer, Ilker ; Ferrari, Raffaele ; Forget, Gael ; Freeland, Howard ; Fujiki, Tetsuichi ; Gehlen, Marion ; Geenan, Blair ; Hallberg, Robert ; Hibiya, Toshiyuki ; Hosoda, Shigeki ; Jayne, Steven R. ; Jochum, Markus ; Johnson, Gregory C. ; Kang, KiRyong ; Kolodziejczyk, Nicolas ; Körtzinger, Arne ; Le Traon, Pierre-Yves ; Lenn, Yueng-Djern ; Maze, Guillaume ; Mork, Kjell Arne ; Morris, Tamaryn ; Nagai, Takeyoshi ; Nash, Jonathan D. ; Naveira Garabato, Alberto C. ; Olsen, Are ; Pattabhi Rama Rao, Eluri ; Prakash, Satya ; Riser, Stephen C. ; Schmechtig, Catherine ; Schmid, Claudia ; Shroyer, Emily L. ; Sterl, Andreas ; Sutton, Philip J. H. ; Talley, Lynne D. ; Tanhua, Toste ; Thierry, Virginie ; Thomalla, Sandy J. ; Toole, John M. ; Troisi, Ariel ; Trull, Thomas W. ; Turton, Jon ; Velez-Belchi, Pedro ; Walczowski, Waldemar ; Wang, Haili ; Wanninkhof, Rik ; Waterhouse, Amy F. ; Waterman, Stephanie N. ; Watson, Andrew J. ; Wilson, Cara ; Wong, Annie P. S. ; Xu, Jianping ; Yasuda, IchiroThe Argo Program has been implemented and sustained for almost two decades, as a global array of about 4000 profiling floats. Argo provides continuous observations of ocean temperature and salinity versus pressure, from the sea surface to 2000 dbar. The successful installation of the Argo array and its innovative data management system arose opportunistically from the combination of great scientific need and technological innovation. Through the data system, Argo provides fundamental physical observations with broad societally-valuable applications, built on the cost-efficient and robust technologies of autonomous profiling floats. Following recent advances in platform and sensor technologies, even greater opportunity exists now than 20 years ago to (i) improve Argo’s global coverage and value beyond the original design, (ii) extend Argo to span the full ocean depth, (iii) add biogeochemical sensors for improved understanding of oceanic cycles of carbon, nutrients, and ecosystems, and (iv) consider experimental sensors that might be included in the future, for example to document the spatial and temporal patterns of ocean mixing. For Core Argo and each of these enhancements, the past, present, and future progression along a path from experimental deployments to regional pilot arrays to global implementation is described. The objective is to create a fully global, top-to-bottom, dynamically complete, and multidisciplinary Argo Program that will integrate seamlessly with satellite and with other in situ elements of the Global Ocean Observing System (Legler et al., 2015). The integrated system will deliver operational reanalysis and forecasting capability, and assessment of the state and variability of the climate system with respect to physical, biogeochemical, and ecosystems parameters. It will enable basic research of unprecedented breadth and magnitude, and a wealth of ocean-education and outreach opportunities.
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DatasetDIC, TA, pH from R/V Pelican cruise conducted in the northern Gulf of Mexico in April 2017(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2019-07-11) Cai, Wei-Jun ; Rabalais, Nancy ; Fennel, KatjaDissolved inorganic carbon, total alkalinity and pH from an R/V Pelican cruise conducted in the northern Gulf of Mexico (27.5 N, 30 N, 88 W, 94 W ) from April 5th to 16th, 2017. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/772513
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DatasetDIC, TA, pH from R/V Pelican cruise conducted in the northern Gulf of Mexico in April and July 2017(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-01-28) Cai, Wei-Jun ; Rabalais, Nancy ; Fennel, KatjaDissolved inorganic carbon, total alkalinity and pH from R/V Pelican cruises conducted in the northern Gulf of Mexico (27.5 N, 30 N, 88 W, 94 W ) from April 5 to 16 and July 7 to 21 in 2017 For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/772513
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PreprintModeling denitrification in aquatic sediments( 2008-10-10) Fennel, Katja ; Brady, Damian C. ; DiToro, Dominic ; Fulweiler, Robinson W. ; Gardner, Wayne S. ; Giblin, Anne E. ; McCarthy, Mark J. ; Rao, Alexandra ; Seitzinger, Sybil P. ; Thouvenot-Korppoo, Marie ; Tobias, Craig R.Sediment denitrification is a major pathway of fixed nitrogen loss from aquatic systems. Due to technical difficulties in measuring this process and its spatial and temporal variability, estimates of local, regional and global denitrification have to rely on a combination of measurements and models. Here we review approaches to describing denitrification in aquatic sediments, ranging from mechanistic diagenetic models to empirical parameterizations of nitrogen fluxes across the sediment-water interface. We also present a compilation of denitrification measurements and ancillary data for different aquatic systems, ranging from freshwater to marine. Based on this data compilation we reevaluate published parameterizations of denitrification. We recommend that future models of denitrification use (1) a combination of mechanistic diagenetic models and measurements where bottom waters are temporally hypoxic or anoxic, and (2) the much simpler correlations between denitrification and sediment oxygen consumption for oxic bottom waters. For our data set, inclusion of bottom water oxygen and nitrate concentrations in a multivariate regression did not improve the statistical fit.
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DatasetUnderway pCO2 from the R/V Pelican cruise GOM_UW_1704 conducted in the Northern Gulf of Mexico in April 2017.(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2019-07-10) Cai, Wei-Jun ; Rabalais, Nancy ; Fennel, KatjaUnderway pCO2 from R/V Pelican cruise conducted in the northern Gulf of Mexico (27.5 N, 30 N, 88 W, 94 W) from April 5th to 16th in 2017. The precision of pCO2 is ±2 µatm. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/770864
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ArticleGlobally consistent quantitative observations of planktonic ecosystems(Frontiers Media, 2019-04-25) Lombard, Fabien ; Boss, Emmanuel S. ; Waite, Anya M. ; Vogt, Meike ; Uitz, Julia ; Stemmann, Lars ; Sosik, Heidi M. ; Schulz, Jan ; Romagnan, Jean-Baptiste ; Picheral, Marc ; Pearlman, Jay ; Ohman, Mark D. ; Niehoff, Barbara ; Möller, Klas O. ; Miloslavich, Patricia ; Lara-Lpez, Ana ; Kudela, Raphael M. ; Lopes, Rubens M. ; Kiko, Rainer ; Karp-Boss, Lee ; Jaffe, Jules S. ; Iversen, Morten H. ; Irisson, Jean-Olivier ; Fennel, Katja ; Hauss, Helena ; Guidi, Lionel ; Gorsky, Gabriel ; Giering, Sarah L. C. ; Gaube, Peter ; Gallager, Scott M. ; Dubelaar, George ; Cowen, Robert K. ; Carlotti, François ; Briseño-Avena, Christian ; Berline, Leo ; Benoit-Bird, Kelly J. ; Bax, Nicholas ; Batten, Sonia ; Ayata, Sakina Dorothée ; Artigas, Luis Felipe ; Appeltans, WardIn this paper we review the technologies available to make globally quantitative observations of particles in general—and plankton in particular—in the world oceans, and for sizes varying from sub-microns to centimeters. Some of these technologies have been available for years while others have only recently emerged. Use of these technologies is critical to improve understanding of the processes that control abundances, distributions and composition of plankton, provide data necessary to constrain and improve ecosystem and biogeochemical models, and forecast changes in marine ecosystems in light of climate change. In this paper we begin by providing the motivation for plankton observations, quantification and diversity qualification on a global scale. We then expand on the state-of-the-art, detailing a variety of relevant and (mostly) mature technologies and measurements, including bulk measurements of plankton, pigment composition, uses of genomic, optical and acoustical methods as well as analysis using particle counters, flow cytometers and quantitative imaging devices. We follow by highlighting the requirements necessary for a plankton observing system, the approach to achieve it and associated challenges. We conclude with ranked action-item recommendations for the next 10 years to move toward our vision of a holistic ocean-wide plankton observing system. Particularly, we suggest to begin with a demonstration project on a GO-SHIP line and/or a long-term observation site and expand from there, ensuring that issues associated with methods, observation tools, data analysis, quality assessment and curation are addressed early in the implementation. Global coordination is key for the success of this vision and will bring new insights on processes associated with nutrient regeneration, ocean production, fisheries and carbon sequestration.
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ArticleIntroduction to special section on The U.S. IOOS Coastal and Ocean Modeling Testbed(John Wiley & Sons, 2013-12-11) Luettich, Richard A. ; Wright, L. Donelson ; Signell, Richard P. ; Friedrichs, Carl T. ; Friedrichs, Marjorie A. M. ; Harding, John ; Fennel, Katja ; Howlett, Eoin ; Graves, Sara J. ; Smith, Elizabeth ; Crane, Gary ; Baltes, RebeccaStrong and strategic collaborations among experts from academia, federal operational centers, and industry have been forged to create a U.S. IOOS Coastal and Ocean Modeling Testbed (COMT). The COMT mission is to accelerate the transition of scientific and technical advances from the coastal and ocean modeling research community to improved operational ocean products and services. This is achieved via the evaluation of existing technology or the development of new technology depending on the status of technology within the research community. The initial phase of the COMT has addressed three coastal and ocean prediction challenges of great societal importance: estuarine hypoxia, shelf hypoxia, and coastal inundation. A fourth effort concentrated on providing and refining the cyberinfrastructure and cyber tools to support the modeling work and to advance interoperability and community access to the COMT archive. This paper presents an overview of the initiation of the COMT, the findings of each team and a discussion of the role of the COMT in research to operations and its interface with the coastal and ocean modeling community in general. Detailed technical results are presented in the accompanying series of 16 technical papers in this special issue.
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ArticleIdeas and perspectives: biogeochemistry - some key foci for the future(European Geosciences Union, 2021-05-19) Bianchi, Thomas S. ; Anand, Madhur ; Bauch, Chris T. ; Canfield, Donald E. ; De Meester, Luc ; Fennel, Katja ; Groffman, Peter M. ; Pace, Michael L. ; Saito, Mak A. ; Simpson, Myrna J.Biogeochemistry has an important role to play in many environmental issues of current concern related to global change and air, water, and soil quality. However, reliable predictions and tangible implementation of solutions, offered by biogeochemistry, will need further integration of disciplines. Here, we refocus on how further developing and strengthening ties between biology, geology, chemistry, and social sciences will advance biogeochemistry through (1) better incorporation of mechanisms, including contemporary evolutionary adaptation, to predict changing biogeochemical cycles, and (2) implementing new and developing insights from social sciences to better understand how sustainable and equitable responses by society are achieved. The challenges for biogeochemists in the 21st century are formidable and will require both the capacity to respond fast to pressing issues (e.g., catastrophic weather events and pandemics) and intense collaboration with government officials, the public, and internationally funded programs. Keys to success will be the degree to which biogeochemistry can make biogeochemical knowledge more available to policy makers and educators about predicting future changes in the biosphere, on timescales from seasons to centuries, in response to climate change and other anthropogenic impacts. Biogeochemistry also has a place in facilitating sustainable and equitable responses by society.
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ArticleRecommendations for plankton measurements on OceanSITES moorings with relevance to other observing sites(Frontiers Media, 2022-07-22) Boss, Emmanuel S. ; Waite, Anya M. ; Karstensen, Johannes ; Trull, Thomas W. ; Muller-Karger, Frank E. ; Sosik, Heidi M. ; Uitz, Julia ; Acinas, Silvia G. ; Fennel, Katja ; Berman-Frank, Ilana ; Thomalla, Sandy J. ; Yamazaki, Hidekatsu ; Batten, Sonia ; Gregori, Gerald ; Richardson, Anthony J. ; Wanninkhof, RikMeasuring plankton and associated variables as part of ocean time-series stations has the potential to revolutionize our understanding of ocean biology and ecology and their ties to ocean biogeochemistry. It will open temporal scales (e.g., resolving diel cycles) not typically sampled as a function of depth. In this review we motivate the addition of biological measurements to time-series sites by detailing science questions they could help address, reviewing existing technology that could be deployed, and providing examples of time-series sites already deploying some of those technologies. We consider here the opportunities that exist through global coordination within the OceanSITES network for long-term (climate) time series station in the open ocean. Especially with respect to data management, global solutions are needed as these are critical to maximize the utility of such data. We conclude by providing recommendations for an implementation plan.