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Volume 13, issue 20
Biogeosciences, 13, 5865–5881, 2016
https://doi.org/10.5194/bg-13-5865-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/bg-13-5865-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Special issue: Hydrography, biogeochemistry, and biology of "dead-zone eddies"...
Biogeosciences, 13, 5865–5881, 2016
https://doi.org/10.5194/bg-13-5865-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/bg-13-5865-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article 28 Oct 2016
Research article | 28 Oct 2016
Characterization of “dead-zone” eddies in the eastern tropical North Atlantic
Florian Schütte et al.
Related authors
Rena Czeschel, Florian Schütte, Robert A. Weller, and Lothar Stramma
Ocean Sci., 14, 731–750, https://doi.org/10.5194/os-14-731-2018, https://doi.org/10.5194/os-14-731-2018, 2018
Short summary
Short summary
The mean circulation on the poleward side of the oxygen minimum zone is overlain by eddy activity playing an important role in the distribution of water masses and oxygen within the OMZ. The activity of different types of eddies was investigated during their westward propagation from the formation area off Peru/Chile into the open ocean. The focus was on the development of eddies, seasonal conditions during their formation, and the change of water mass properties transported within the eddies.
Johannes Karstensen, Florian Schütte, Alice Pietri, Gerd Krahmann, Björn Fiedler, Damian Grundle, Helena Hauss, Arne Körtzinger, Carolin R. Löscher, Pierre Testor, Nuno Vieira, and Martin Visbeck
Biogeosciences, 14, 2167–2181, https://doi.org/10.5194/bg-14-2167-2017, https://doi.org/10.5194/bg-14-2167-2017, 2017
Short summary
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High-resolution observational data from underwater gliders and ships are used to investigate drivers and pathways of nutrient upwelling in high-productive whirling ecosystems (eddies). The data suggest that the upwelling is created by the interaction of wind-induced internal waves with the local rotation of the eddy. Because of differences in nutrient and oxygen pathways, a low-oxygen core is established at shallow depth in the high-productive eddies.
Björn Fiedler, Damian S. Grundle, Florian Schütte, Johannes Karstensen, Carolin R. Löscher, Helena Hauss, Hannes Wagner, Alexandra Loginova, Rainer Kiko, Péricles Silva, Toste Tanhua, and Arne Körtzinger
Biogeosciences, 13, 5633–5647, https://doi.org/10.5194/bg-13-5633-2016, https://doi.org/10.5194/bg-13-5633-2016, 2016
Short summary
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Oxygen-depleted mesoscale features in the open eastern tropical North Atlantic, which are formed in the Mauritanian upwelling region, were discovered recently. This study examines biogeochemical structure and magnitudes of related processes within these isolated water masses. We found very low oxygen concentrations and strongly enhanced acidity at near-surface depth. Oxygen utilization and downward carbon export were found to exceed known values for this ocean region.
Florian Schütte, Peter Brandt, and Johannes Karstensen
Ocean Sci., 12, 663–685, https://doi.org/10.5194/os-12-663-2016, https://doi.org/10.5194/os-12-663-2016, 2016
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We want to examine the characteristics of mesoscale eddies in the tropical northeastern Atlantic. They serve as transport agents, exporting water from the coast into the open ocean. Traditionally eddies are categorized with respect to their rotation: cyclonic and anticyclonic. But we could identify, with a combination of different satellite products, a third type called "anticyclonic mode-water eddy" transporting much larger anomalies. We propose a distinction into three classes for further studies.
Helena Hauss, Svenja Christiansen, Florian Schütte, Rainer Kiko, Miryam Edvam Lima, Elizandro Rodrigues, Johannes Karstensen, Carolin R. Löscher, Arne Körtzinger, and Björn Fiedler
Biogeosciences, 13, 1977–1989, https://doi.org/10.5194/bg-13-1977-2016, https://doi.org/10.5194/bg-13-1977-2016, 2016
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In a low-oxygen eddy in the tropical Atlantic, total zooplankton biomass was increased. Larger plankton avoided the oxygen minimum zone (OMZ, < 20 µmol O2 kg−1). We identified four strategies by different plankton groups: (i) shallow OMZ avoidance and compression at surface, (ii) migration to shallow OMZ core during daytime, migration to surface at nighttime, (iii) residing in shallow OMZ day and night and (iv) migration through the shallow OMZ from oxygenated depths to surface and back.
C. R. Löscher, M. A. Fischer, S. C. Neulinger, B. Fiedler, M. Philippi, F. Schütte, A. Singh, H. Hauss, J. Karstensen, A. Körtzinger, S. Künzel, and R. A. Schmitz
Biogeosciences, 12, 7467–7482, https://doi.org/10.5194/bg-12-7467-2015, https://doi.org/10.5194/bg-12-7467-2015, 2015
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The waters of the tropical Atlantic Open Ocean usually contain comparably high concentrations of oxygen. Now, it became clear that there are watermasses related to eddies that are nearly anoxic. We surveyed one of those eddies and found a biosphere that largely differed from the usual biosphere present in this area with a specific community responsible for primary production and for degradation processes. Further, we found the very first indication for active nitrogen loss in the open Atlantic.
J. Karstensen, B. Fiedler, F. Schütte, P. Brandt, A. Körtzinger, G. Fischer, R. Zantopp, J. Hahn, M. Visbeck, and D. Wallace
Biogeosciences, 12, 2597–2605, https://doi.org/10.5194/bg-12-2597-2015, https://doi.org/10.5194/bg-12-2597-2015, 2015
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This study is the first report of the formation of dead zones in the open ocean. A combination of multiple ocean observing system elements (mooring, floats, satellites, ships) allowed us to reconstruct the generation of the dead zones and to connect the formation to enhanced respiration within mesoscale ocean eddies. The dead zones present specific threats to the ecosystem, such as the interruption of the diurnal migration of zooplankters.
Josefine Herrford, Peter Brandt, Torsten Kanzow, Rebecca Hummels, Moacyr Araujo, and Jonathan V. Durgadoo
Ocean Sci. Discuss., https://doi.org/10.5194/os-2020-55, https://doi.org/10.5194/os-2020-55, 2020
Revised manuscript has not been submitted
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The Atlantic Meridional Overturning Circulation (AMOC) is an important component of the climate system. Understanding its structure and variability is a key priority for many scientists. Here, we present the first estimate of AMOC variations for the tropical South Atlantic – from the TRACOS array at 11° S. Over the observed period, the AMOC is dominated by seasonal variability. We investigate the respective mechanisms with an ocean model and find different wind-forced waves to play a big role.
Manuela van Pinxteren, Khanneh Wadinga Fomba, Nadja Triesch, Christian Stolle, Oliver Wurl, Enno Bahlmann, Xianda Gong, Jens Voigtländer, Heike Wex, Tiera-Brandy Robinson, Stefan Barthel, Sebastian Zeppenfeld, Erik Hans Hoffmann, Marie Roveretto, Chunlin Li, Benoit Grosselin, Veronique Daële, Fabian Senf, Dominik van Pinxteren, Malena Manzi, Nicolás Zabalegui, Sanja Frka, Blaženka Gašparović, Ryan Pereira, Tao Li, Liang Wen, Jiarong Li, Chao Zhu, Hui Chen, Jianmin Chen, Björn Fiedler, Wolf von Tümpling, Katie Alana Read, Shalini Punjabi, Alastair Charles Lewis, James Roland Hopkins, Lucy Jane Carpenter, Ilka Peeken, Tim Rixen, Detlef Schulz-Bull, María Eugenia Monge, Abdelwahid Mellouki, Christian George, Frank Stratmann, and Hartmut Herrmann
Atmos. Chem. Phys., 20, 6921–6951, https://doi.org/10.5194/acp-20-6921-2020, https://doi.org/10.5194/acp-20-6921-2020, 2020
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An introduction to a comprehensive field campaign performed at the Cape Verde Atmospheric Observatory regarding ocean–atmosphere interactions is given. Chemical, physical, biological and meteorological techniques were applied, and measurements of bulk water, the sea surface microlayer, cloud water and ambient aerosol particles took place. Oceanic compounds were found to be transferred to atmospheric aerosol and to the cloud level; however, sea spray contributions to CCN and INPs were limited.
Anna Canning, Arne Körtzinger, Peer Fietzek, and Gregor Rehder
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-128, https://doi.org/10.5194/bg-2020-128, 2020
Revised manuscript under review for BG
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The manuscript describes a novel, fully autonomous, multi-gas flow-through setup for multiple gases that combines established high-quality oceanographic sensors in a small and robust system, designed to use across all salinities from all types of platforms. We describe the system and its performance in all relevant detail, including corrections, which improve the accuracy of these sensors. Illustrating how simultaneous multi-gas set up can provide extremely high spatiotemporal resolution.
Katharina Seelmann, Martha Gledhill, Steffen Aßmann, and Arne Körtzinger
Ocean Sci., 16, 535–544, https://doi.org/10.5194/os-16-535-2020, https://doi.org/10.5194/os-16-535-2020, 2020
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We investigated the impact of indicator dye impurities on spectrophotometric seawater measurements, especially how they may influence the drift behavior and the measurement quality of an autonomous analyzer using this indicator. These measurements are important for ocean carbon observations. This work revealed that impurities up to a quantity of 2 % do not influence the measurement drift and quality. Higher impurity levels lead to a changing drift behavior and quality deteriorations.
Henk-Jan Hoving, Svenja Christiansen, Eduard Fabrizius, Helena Hauss, Rainer Kiko, Peter Linke, Philipp Neitzel, Uwe Piatkowski, and Arne Körtzinger
Ocean Sci., 15, 1327–1340, https://doi.org/10.5194/os-15-1327-2019, https://doi.org/10.5194/os-15-1327-2019, 2019
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The pelagic in situ observation system (PELAGIOS) is a towed observation system with HD video camera and environmental sensors. It is used for pelagic video transects down to 3000 m. The system enables the visualization and exploration of pelagic organisms (> 1 cm), in particular delicate gelatinous fauna, which cannot be captured by nets. The video and hydrographic data give insight into the biodiversity, abundance, and distribution of oceanic pelagic organisms from the surface to the deep sea.
Tim Fischer, Annette Kock, Damian L. Arévalo-Martínez, Marcus Dengler, Peter Brandt, and Hermann W. Bange
Biogeosciences, 16, 2307–2328, https://doi.org/10.5194/bg-16-2307-2019, https://doi.org/10.5194/bg-16-2307-2019, 2019
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We investigated air–sea gas exchange in oceanic upwelling regions for the case of nitrous oxide off Peru. In this region, routine concentration measurements from ships at 5 m or 10 m depth prove to overestimate surface (bulk) concentration. Thus, standard estimates of gas exchange will show systematic error. This is due to very shallow stratified layers that inhibit exchange between surface water and waters below and can exist for several days. Maximum bias occurs in moderate wind conditions.
Soeren Thomsen, Johannes Karstensen, Rainer Kiko, Gerd Krahmann, Marcus Dengler, and Anja Engel
Biogeosciences, 16, 979–998, https://doi.org/10.5194/bg-16-979-2019, https://doi.org/10.5194/bg-16-979-2019, 2019
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Physical and biogeochemical observations from an autonomous underwater vehicle in combination with ship-based measurements are used to investigate remote and local drivers of the oxygen and nutrient variability off Mauritania. Beside the transport of oxygen and nutrients characteristics from remote areas towards Mauritania also local remineralization of organic material close to the seabed seems to be important for the distribution of oxygen and nutrients.
Mochamad Furqon Azis Ismail, Joachim Ribbe, Johannes Karstensen, and Vincent Rossi
Ocean Sci. Discuss., https://doi.org/10.5194/os-2018-142, https://doi.org/10.5194/os-2018-142, 2019
Publication in OS not foreseen
Jürgen Fischer, Johannes Karstensen, Marilena Oltmanns, and Sunke Schmidtko
Ocean Sci., 14, 1167–1183, https://doi.org/10.5194/os-14-1167-2018, https://doi.org/10.5194/os-14-1167-2018, 2018
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Based on nearly 17 years of profiling (Argo) float data, high-resolution (~ 25 km grid) maps of mean flow and eddy kinetic energy (EKE) were constructed for the intermediate to deep subpolar North Atlantic. Robust boundary currents along topographic slopes, mid-basin advective pathways, and stagnation regimes were identified. The ratio of mean flow vs. the square root of EKE indicates regions dominated by advection, and large regions in which eddy diffusion prevails.
Rena Czeschel, Florian Schütte, Robert A. Weller, and Lothar Stramma
Ocean Sci., 14, 731–750, https://doi.org/10.5194/os-14-731-2018, https://doi.org/10.5194/os-14-731-2018, 2018
Short summary
Short summary
The mean circulation on the poleward side of the oxygen minimum zone is overlain by eddy activity playing an important role in the distribution of water masses and oxygen within the OMZ. The activity of different types of eddies was investigated during their westward propagation from the formation area off Peru/Chile into the open ocean. The focus was on the development of eddies, seasonal conditions during their formation, and the change of water mass properties transported within the eddies.
Yao Fu, Johannes Karstensen, and Peter Brandt
Ocean Sci., 14, 589–616, https://doi.org/10.5194/os-14-589-2018, https://doi.org/10.5194/os-14-589-2018, 2018
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Hydrographic analysis in the Atlantic along 14.5° N and 24.5° N shows that between the periods of 1989/92 and 2013/15, the Antarctic Intermediate Water became warmer and saltier at 14.5° N, and that the Antarctic Bottom Water became lighter at both latitudes. By applying a box inverse model, the Atlantic Meridional Overturning Circulation (AMOC) was determined. Comparison among the inverse solution, GECCO2, RAPID, and MOVE shows that the AMOC has not significantly changed in the past 20 years.
Fabrice Ardhuin, Yevgueny Aksenov, Alvise Benetazzo, Laurent Bertino, Peter Brandt, Eric Caubet, Bertrand Chapron, Fabrice Collard, Sophie Cravatte, Jean-Marc Delouis, Frederic Dias, Gérald Dibarboure, Lucile Gaultier, Johnny Johannessen, Anton Korosov, Georgy Manucharyan, Dimitris Menemenlis, Melisa Menendez, Goulven Monnier, Alexis Mouche, Frédéric Nouguier, George Nurser, Pierre Rampal, Ad Reniers, Ernesto Rodriguez, Justin Stopa, Céline Tison, Clément Ubelmann, Erik van Sebille, and Jiping Xie
Ocean Sci., 14, 337–354, https://doi.org/10.5194/os-14-337-2018, https://doi.org/10.5194/os-14-337-2018, 2018
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The Sea surface KInematics Multiscale (SKIM) monitoring mission is a proposal for a future satellite that is designed to measure ocean currents and waves. Using a Doppler radar, the accurate measurement of currents requires the removal of the mean velocity due to ocean wave motions. This paper describes the main processing steps needed to produce currents and wave data from the radar measurements. With this technique, SKIM can provide unprecedented coverage and resolution, over the global ocean.
Corinne Le Quéré, Robbie M. Andrew, Pierre Friedlingstein, Stephen Sitch, Julia Pongratz, Andrew C. Manning, Jan Ivar Korsbakken, Glen P. Peters, Josep G. Canadell, Robert B. Jackson, Thomas A. Boden, Pieter P. Tans, Oliver D. Andrews, Vivek K. Arora, Dorothee C. E. Bakker, Leticia Barbero, Meike Becker, Richard A. Betts, Laurent Bopp, Frédéric Chevallier, Louise P. Chini, Philippe Ciais, Catherine E. Cosca, Jessica Cross, Kim Currie, Thomas Gasser, Ian Harris, Judith Hauck, Vanessa Haverd, Richard A. Houghton, Christopher W. Hunt, George Hurtt, Tatiana Ilyina, Atul K. Jain, Etsushi Kato, Markus Kautz, Ralph F. Keeling, Kees Klein Goldewijk, Arne Körtzinger, Peter Landschützer, Nathalie Lefèvre, Andrew Lenton, Sebastian Lienert, Ivan Lima, Danica Lombardozzi, Nicolas Metzl, Frank Millero, Pedro M. S. Monteiro, David R. Munro, Julia E. M. S. Nabel, Shin-ichiro Nakaoka, Yukihiro Nojiri, X. Antonio Padin, Anna Peregon, Benjamin Pfeil, Denis Pierrot, Benjamin Poulter, Gregor Rehder, Janet Reimer, Christian Rödenbeck, Jörg Schwinger, Roland Séférian, Ingunn Skjelvan, Benjamin D. Stocker, Hanqin Tian, Bronte Tilbrook, Francesco N. Tubiello, Ingrid T. van der Laan-Luijkx, Guido R. van der Werf, Steven van Heuven, Nicolas Viovy, Nicolas Vuichard, Anthony P. Walker, Andrew J. Watson, Andrew J. Wiltshire, Sönke Zaehle, and Dan Zhu
Earth Syst. Sci. Data, 10, 405–448, https://doi.org/10.5194/essd-10-405-2018, https://doi.org/10.5194/essd-10-405-2018, 2018
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The Global Carbon Budget 2017 describes data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. It is the 12th annual update and the 6th published in this journal.
Vincent Saderne, Peer Fietzek, Jens Daniel Müller, Arne Körtzinger, and Claas Hiebenthal
Biogeosciences Discuss., https://doi.org/10.5194/bg-2017-351, https://doi.org/10.5194/bg-2017-351, 2017
Preprint withdrawn
Yao Fu, Johannes Karstensen, and Peter Brandt
Ocean Sci., 13, 531–549, https://doi.org/10.5194/os-13-531-2017, https://doi.org/10.5194/os-13-531-2017, 2017
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Meridional Ekman transport in the tropical Atlantic was estimated directly by using observed ageostrophic velocity, and indirectly by using wind stress data. The direct and indirect methods agree well with each other. The top of the pycnocline represents the Ekman depth better than the mixed layer depth and a constant depth. The Ekman heat and salt fluxes calculated from sea surface temperature and salinity or from high-resolution temperature and salinity profile data differ only marginally.
Johannes Hahn, Peter Brandt, Sunke Schmidtko, and Gerd Krahmann
Ocean Sci., 13, 551–576, https://doi.org/10.5194/os-13-551-2017, https://doi.org/10.5194/os-13-551-2017, 2017
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Recent studies have shown that the eastern tropical North Atlantic is subject to a strong decrease of the oceanic oxygen concentration in the upper 1000 m from the 1960s to today. By analyzing a broad observational data set, this study found an even stronger oxygen decrease in the upper 400 m throughout the past decade, whereas oxygen increase was found below (400–1000 m). Changes in the strength of the zonal currents are the most likely reason for the observed decadal oxygen changes.
Johannes Karstensen, Florian Schütte, Alice Pietri, Gerd Krahmann, Björn Fiedler, Damian Grundle, Helena Hauss, Arne Körtzinger, Carolin R. Löscher, Pierre Testor, Nuno Vieira, and Martin Visbeck
Biogeosciences, 14, 2167–2181, https://doi.org/10.5194/bg-14-2167-2017, https://doi.org/10.5194/bg-14-2167-2017, 2017
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High-resolution observational data from underwater gliders and ships are used to investigate drivers and pathways of nutrient upwelling in high-productive whirling ecosystems (eddies). The data suggest that the upwelling is created by the interaction of wind-induced internal waves with the local rotation of the eddy. Because of differences in nutrient and oxygen pathways, a low-oxygen core is established at shallow depth in the high-productive eddies.
Henry C. Bittig and Arne Körtzinger
Ocean Sci., 13, 1–11, https://doi.org/10.5194/os-13-1-2017, https://doi.org/10.5194/os-13-1-2017, 2017
Corinne Le Quéré, Robbie M. Andrew, Josep G. Canadell, Stephen Sitch, Jan Ivar Korsbakken, Glen P. Peters, Andrew C. Manning, Thomas A. Boden, Pieter P. Tans, Richard A. Houghton, Ralph F. Keeling, Simone Alin, Oliver D. Andrews, Peter Anthoni, Leticia Barbero, Laurent Bopp, Frédéric Chevallier, Louise P. Chini, Philippe Ciais, Kim Currie, Christine Delire, Scott C. Doney, Pierre Friedlingstein, Thanos Gkritzalis, Ian Harris, Judith Hauck, Vanessa Haverd, Mario Hoppema, Kees Klein Goldewijk, Atul K. Jain, Etsushi Kato, Arne Körtzinger, Peter Landschützer, Nathalie Lefèvre, Andrew Lenton, Sebastian Lienert, Danica Lombardozzi, Joe R. Melton, Nicolas Metzl, Frank Millero, Pedro M. S. Monteiro, David R. Munro, Julia E. M. S. Nabel, Shin-ichiro Nakaoka, Kevin O'Brien, Are Olsen, Abdirahman M. Omar, Tsuneo Ono, Denis Pierrot, Benjamin Poulter, Christian Rödenbeck, Joe Salisbury, Ute Schuster, Jörg Schwinger, Roland Séférian, Ingunn Skjelvan, Benjamin D. Stocker, Adrienne J. Sutton, Taro Takahashi, Hanqin Tian, Bronte Tilbrook, Ingrid T. van der Laan-Luijkx, Guido R. van der Werf, Nicolas Viovy, Anthony P. Walker, Andrew J. Wiltshire, and Sönke Zaehle
Earth Syst. Sci. Data, 8, 605–649, https://doi.org/10.5194/essd-8-605-2016, https://doi.org/10.5194/essd-8-605-2016, 2016
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The Global Carbon Budget 2016 is the 11th annual update of emissions of carbon dioxide (CO2) and their partitioning among the atmosphere, land, and ocean. This data synthesis brings together measurements, statistical information, and analyses of model results in order to provide an assessment of the global carbon budget and their uncertainties for years 1959 to 2015, with a projection for year 2016.
Meike Becker, Nils Andersen, Helmut Erlenkeuser, Matthew P. Humphreys, Toste Tanhua, and Arne Körtzinger
Earth Syst. Sci. Data, 8, 559–570, https://doi.org/10.5194/essd-8-559-2016, https://doi.org/10.5194/essd-8-559-2016, 2016
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The stable carbon isotope composition of dissolved inorganic carbon (δ13C-DIC) can be used to quantify fluxes within the marine carbon system such as the exchange between ocean and atmosphere or the amount of anthropogenic carbon in the water column. In this study, an internally consistent δ13C-DIC dataset for the North Atlantic is presented. The data have undergone a secondary quality control during which systematic biases between the respective cruises have been quantified and adjusted.
Björn Fiedler, Damian S. Grundle, Florian Schütte, Johannes Karstensen, Carolin R. Löscher, Helena Hauss, Hannes Wagner, Alexandra Loginova, Rainer Kiko, Péricles Silva, Toste Tanhua, and Arne Körtzinger
Biogeosciences, 13, 5633–5647, https://doi.org/10.5194/bg-13-5633-2016, https://doi.org/10.5194/bg-13-5633-2016, 2016
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Oxygen-depleted mesoscale features in the open eastern tropical North Atlantic, which are formed in the Mauritanian upwelling region, were discovered recently. This study examines biogeochemical structure and magnitudes of related processes within these isolated water masses. We found very low oxygen concentrations and strongly enhanced acidity at near-surface depth. Oxygen utilization and downward carbon export were found to exceed known values for this ocean region.
Dorothee C. E. Bakker, Benjamin Pfeil, Camilla S. Landa, Nicolas Metzl, Kevin M. O'Brien, Are Olsen, Karl Smith, Cathy Cosca, Sumiko Harasawa, Stephen D. Jones, Shin-ichiro Nakaoka, Yukihiro Nojiri, Ute Schuster, Tobias Steinhoff, Colm Sweeney, Taro Takahashi, Bronte Tilbrook, Chisato Wada, Rik Wanninkhof, Simone R. Alin, Carlos F. Balestrini, Leticia Barbero, Nicholas R. Bates, Alejandro A. Bianchi, Frédéric Bonou, Jacqueline Boutin, Yann Bozec, Eugene F. Burger, Wei-Jun Cai, Robert D. Castle, Liqi Chen, Melissa Chierici, Kim Currie, Wiley Evans, Charles Featherstone, Richard A. Feely, Agneta Fransson, Catherine Goyet, Naomi Greenwood, Luke Gregor, Steven Hankin, Nick J. Hardman-Mountford, Jérôme Harlay, Judith Hauck, Mario Hoppema, Matthew P. Humphreys, Christopher W. Hunt, Betty Huss, J. Severino P. Ibánhez, Truls Johannessen, Ralph Keeling, Vassilis Kitidis, Arne Körtzinger, Alex Kozyr, Evangelia Krasakopoulou, Akira Kuwata, Peter Landschützer, Siv K. Lauvset, Nathalie Lefèvre, Claire Lo Monaco, Ansley Manke, Jeremy T. Mathis, Liliane Merlivat, Frank J. Millero, Pedro M. S. Monteiro, David R. Munro, Akihiko Murata, Timothy Newberger, Abdirahman M. Omar, Tsuneo Ono, Kristina Paterson, David Pearce, Denis Pierrot, Lisa L. Robbins, Shu Saito, Joe Salisbury, Reiner Schlitzer, Bernd Schneider, Roland Schweitzer, Rainer Sieger, Ingunn Skjelvan, Kevin F. Sullivan, Stewart C. Sutherland, Adrienne J. Sutton, Kazuaki Tadokoro, Maciej Telszewski, Matthias Tuma, Steven M. A. C. van Heuven, Doug Vandemark, Brian Ward, Andrew J. Watson, and Suqing Xu
Earth Syst. Sci. Data, 8, 383–413, https://doi.org/10.5194/essd-8-383-2016, https://doi.org/10.5194/essd-8-383-2016, 2016
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Version 3 of the Surface Ocean CO2 Atlas (www.socat.info) has 14.5 million CO2 (carbon dioxide) values for the years 1957 to 2014 covering the global oceans and coastal seas. Version 3 is an update to version 2 with a longer record and 44 % more CO2 values. The CO2 measurements have been made on ships, fixed moorings and drifting buoys. SOCAT enables quantification of the ocean carbon sink and ocean acidification, as well as model evaluation, thus informing climate negotiations.
Lothar Stramma, Tim Fischer, Damian S. Grundle, Gerd Krahmann, Hermann W. Bange, and Christa A. Marandino
Ocean Sci., 12, 861–873, https://doi.org/10.5194/os-12-861-2016, https://doi.org/10.5194/os-12-861-2016, 2016
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Results from a research cruise on R/V Sonne to the eastern tropical Pacific in October 2015 during the 2015–2016 El Niño show the transition of current, hydrographic, and nutrient conditions to El Niño conditions in the eastern tropical Pacific in October 2015. Although in early 2015 the El Niño was strong and in October 2015 showed a clear El Niño influence on the EUC, in the eastern tropical Pacific the measurements only showed developing El Niño water mass distributions.
Carolin R. Löscher, Hermann W. Bange, Ruth A. Schmitz, Cameron M. Callbeck, Anja Engel, Helena Hauss, Torsten Kanzow, Rainer Kiko, Gaute Lavik, Alexandra Loginova, Frank Melzner, Judith Meyer, Sven C. Neulinger, Markus Pahlow, Ulf Riebesell, Harald Schunck, Sören Thomsen, and Hannes Wagner
Biogeosciences, 13, 3585–3606, https://doi.org/10.5194/bg-13-3585-2016, https://doi.org/10.5194/bg-13-3585-2016, 2016
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The ocean loses oxygen due to climate change. Addressing this issue in tropical ocean regions (off Peru and Mauritania), we aimed to understand the effects of oxygen depletion on various aspects of marine biogeochemistry, including primary production and export production, the nitrogen cycle, greenhouse gas production, organic matter fluxes and remineralization, and the role of zooplankton and viruses.
Gerhard Fischer, Johannes Karstensen, Oscar Romero, Karl-Heinz Baumann, Barbara Donner, Jens Hefter, Gesine Mollenhauer, Morten Iversen, Björn Fiedler, Ivanice Monteiro, and Arne Körtzinger
Biogeosciences, 13, 3203–3223, https://doi.org/10.5194/bg-13-3203-2016, https://doi.org/10.5194/bg-13-3203-2016, 2016
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Particle fluxes at the Cape Verde Ocean Observatory in the eastern tropical North Atlantic for the period December 2009 until May 2011 are discussed based on deep sediment trap time-series data collected at 1290 and 3439 m water depths. The typically open-ocean flux pattern with weak seasonality is modified by the appearance of a highly productive and low oxygen eddy in winter 2010. The eddy passage was accompanied by high biogenic and lithogenic fluxes, lasting from December 2009 to May 2010.
Marcela Cornejo D'Ottone, Luis Bravo, Marcel Ramos, Oscar Pizarro, Johannes Karstensen, Mauricio Gallegos, Marco Correa-Ramirez, Nelson Silva, Laura Farias, and Lee Karp-Boss
Biogeosciences, 13, 2971–2979, https://doi.org/10.5194/bg-13-2971-2016, https://doi.org/10.5194/bg-13-2971-2016, 2016
Florian Schütte, Peter Brandt, and Johannes Karstensen
Ocean Sci., 12, 663–685, https://doi.org/10.5194/os-12-663-2016, https://doi.org/10.5194/os-12-663-2016, 2016
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We want to examine the characteristics of mesoscale eddies in the tropical northeastern Atlantic. They serve as transport agents, exporting water from the coast into the open ocean. Traditionally eddies are categorized with respect to their rotation: cyclonic and anticyclonic. But we could identify, with a combination of different satellite products, a third type called "anticyclonic mode-water eddy" transporting much larger anomalies. We propose a distinction into three classes for further studies.
Rainer Kiko, Helena Hauss, Friedrich Buchholz, and Frank Melzner
Biogeosciences, 13, 2241–2255, https://doi.org/10.5194/bg-13-2241-2016, https://doi.org/10.5194/bg-13-2241-2016, 2016
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The diel vertical migration of zooplankton and nekton results in an active export of carbon and nitrogen from the oceans surface layer. In vast areas of the ocean the daytime distribution depth of migrating organisms corresponds to the core of an oxygen minimum zone (OMZ). We show that exposure to OMZ conditions can result in a strong depression of respiration and ammonium excretion in zooplankton, a fact that needs to be considered when calculating carbon and nitrogen fluxes in OMZ regions.
Helena Hauss, Svenja Christiansen, Florian Schütte, Rainer Kiko, Miryam Edvam Lima, Elizandro Rodrigues, Johannes Karstensen, Carolin R. Löscher, Arne Körtzinger, and Björn Fiedler
Biogeosciences, 13, 1977–1989, https://doi.org/10.5194/bg-13-1977-2016, https://doi.org/10.5194/bg-13-1977-2016, 2016
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In a low-oxygen eddy in the tropical Atlantic, total zooplankton biomass was increased. Larger plankton avoided the oxygen minimum zone (OMZ, < 20 µmol O2 kg−1). We identified four strategies by different plankton groups: (i) shallow OMZ avoidance and compression at surface, (ii) migration to shallow OMZ core during daytime, migration to surface at nighttime, (iii) residing in shallow OMZ day and night and (iv) migration through the shallow OMZ from oxygenated depths to surface and back.
J. Meyer, C. R. Löscher, S. C. Neulinger, A. F. Reichel, A. Loginova, C. Borchard, R. A. Schmitz, H. Hauss, R. Kiko, and U. Riebesell
Biogeosciences, 13, 781–794, https://doi.org/10.5194/bg-13-781-2016, https://doi.org/10.5194/bg-13-781-2016, 2016
L. Stramma, R. Czeschel, T. Tanhua, P. Brandt, M. Visbeck, and B. S. Giese
Ocean Sci., 12, 153–167, https://doi.org/10.5194/os-12-153-2016, https://doi.org/10.5194/os-12-153-2016, 2016
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The subsurface circulation in the eastern tropical North Atlantic OMZ is derived from velocity, float and tracer data and data assimilation results, and shows a cyclonic flow around the Guinea Dome reaching into the oxygen minimum zone. The stronger cyclonic flow around the Guinea Dome in 2009 seem to be connected to a strong Atlantic Meridional Mode (AMM) event.
A continuous deoxygenation trend of the low oxygen layer was confirmed.
Eddy influence is weak south of the Cape Verde Islands.
S. Walter, A. Kock, T. Steinhoff, B. Fiedler, P. Fietzek, J. Kaiser, M. Krol, M. E. Popa, Q. Chen, T. Tanhua, and T. Röckmann
Biogeosciences, 13, 323–340, https://doi.org/10.5194/bg-13-323-2016, https://doi.org/10.5194/bg-13-323-2016, 2016
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Oceans are a source of H2, an indirect greenhouse gas. Measurements constraining the temporal and spatial patterns of oceanic H2 emissions are sparse and although H2 is assumed to be produced mainly biologically, direct evidence for biogenic marine production was lacking. By analyzing the H2 isotopic composition (δD) we were able to constrain the global H2 budget in more detail, verify biogenic production and point to additional sources. We also showed that current models are reasonably working.
C. R. Löscher, M. A. Fischer, S. C. Neulinger, B. Fiedler, M. Philippi, F. Schütte, A. Singh, H. Hauss, J. Karstensen, A. Körtzinger, S. Künzel, and R. A. Schmitz
Biogeosciences, 12, 7467–7482, https://doi.org/10.5194/bg-12-7467-2015, https://doi.org/10.5194/bg-12-7467-2015, 2015
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The waters of the tropical Atlantic Open Ocean usually contain comparably high concentrations of oxygen. Now, it became clear that there are watermasses related to eddies that are nearly anoxic. We surveyed one of those eddies and found a biosphere that largely differed from the usual biosphere present in this area with a specific community responsible for primary production and for degradation processes. Further, we found the very first indication for active nitrogen loss in the open Atlantic.
A. N. Loginova, C. Borchard, J. Meyer, H. Hauss, R. Kiko, and A. Engel
Biogeosciences, 12, 6897–6914, https://doi.org/10.5194/bg-12-6897-2015, https://doi.org/10.5194/bg-12-6897-2015, 2015
A. Engel, C. Borchard, A. Loginova, J. Meyer, H. Hauss, and R. Kiko
Biogeosciences, 12, 5647–5665, https://doi.org/10.5194/bg-12-5647-2015, https://doi.org/10.5194/bg-12-5647-2015, 2015
V. Saderne, P. Fietzek, S. Aßmann, A. Körtzinger, and C. Hiebenthal
Biogeosciences Discuss., https://doi.org/10.5194/bgd-12-11423-2015, https://doi.org/10.5194/bgd-12-11423-2015, 2015
Revised manuscript not accepted
J. Karstensen, B. Fiedler, F. Schütte, P. Brandt, A. Körtzinger, G. Fischer, R. Zantopp, J. Hahn, M. Visbeck, and D. Wallace
Biogeosciences, 12, 2597–2605, https://doi.org/10.5194/bg-12-2597-2015, https://doi.org/10.5194/bg-12-2597-2015, 2015
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This study is the first report of the formation of dead zones in the open ocean. A combination of multiple ocean observing system elements (mooring, floats, satellites, ships) allowed us to reconstruct the generation of the dead zones and to connect the formation to enhanced respiration within mesoscale ocean eddies. The dead zones present specific threats to the ecosystem, such as the interruption of the diurnal migration of zooplankters.
P. Brandt, H. W. Bange, D. Banyte, M. Dengler, S.-H. Didwischus, T. Fischer, R. J. Greatbatch, J. Hahn, T. Kanzow, J. Karstensen, A. Körtzinger, G. Krahmann, S. Schmidtko, L. Stramma, T. Tanhua, and M. Visbeck
Biogeosciences, 12, 489–512, https://doi.org/10.5194/bg-12-489-2015, https://doi.org/10.5194/bg-12-489-2015, 2015
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Our observational study looks at the structure of the eastern tropical North Atlantic (ETNA) oxygen minimum zone (OMZ) in comparison with the less-ventilated, eastern tropical South Pacific OMZ. We quantify the OMZ’s oxygen budget composed of consumption, advection, lateral and vertical mixing. Substantial oxygen variability is observed on interannual to multidecadal timescales. The deoxygenation of the ETNA OMZ during the last decades represents a substantial imbalance of the oxygen budget.
J. Karstensen, T. Liblik, J. Fischer, K. Bumke, and G. Krahmann
Biogeosciences, 11, 3603–3617, https://doi.org/10.5194/bg-11-3603-2014, https://doi.org/10.5194/bg-11-3603-2014, 2014
C. Le Quéré, G. P. Peters, R. J. Andres, R. M. Andrew, T. A. Boden, P. Ciais, P. Friedlingstein, R. A. Houghton, G. Marland, R. Moriarty, S. Sitch, P. Tans, A. Arneth, A. Arvanitis, D. C. E. Bakker, L. Bopp, J. G. Canadell, L. P. Chini, S. C. Doney, A. Harper, I. Harris, J. I. House, A. K. Jain, S. D. Jones, E. Kato, R. F. Keeling, K. Klein Goldewijk, A. Körtzinger, C. Koven, N. Lefèvre, F. Maignan, A. Omar, T. Ono, G.-H. Park, B. Pfeil, B. Poulter, M. R. Raupach, P. Regnier, C. Rödenbeck, S. Saito, J. Schwinger, J. Segschneider, B. D. Stocker, T. Takahashi, B. Tilbrook, S. van Heuven, N. Viovy, R. Wanninkhof, A. Wiltshire, and S. Zaehle
Earth Syst. Sci. Data, 6, 235–263, https://doi.org/10.5194/essd-6-235-2014, https://doi.org/10.5194/essd-6-235-2014, 2014
D. C. E. Bakker, B. Pfeil, K. Smith, S. Hankin, A. Olsen, S. R. Alin, C. Cosca, S. Harasawa, A. Kozyr, Y. Nojiri, K. M. O'Brien, U. Schuster, M. Telszewski, B. Tilbrook, C. Wada, J. Akl, L. Barbero, N. R. Bates, J. Boutin, Y. Bozec, W.-J. Cai, R. D. Castle, F. P. Chavez, L. Chen, M. Chierici, K. Currie, H. J. W. de Baar, W. Evans, R. A. Feely, A. Fransson, Z. Gao, B. Hales, N. J. Hardman-Mountford, M. Hoppema, W.-J. Huang, C. W. Hunt, B. Huss, T. Ichikawa, T. Johannessen, E. M. Jones, S. D. Jones, S. Jutterström, V. Kitidis, A. Körtzinger, P. Landschützer, S. K. Lauvset, N. Lefèvre, A. B. Manke, J. T. Mathis, L. Merlivat, N. Metzl, A. Murata, T. Newberger, A. M. Omar, T. Ono, G.-H. Park, K. Paterson, D. Pierrot, A. F. Ríos, C. L. Sabine, S. Saito, J. Salisbury, V. V. S. S. Sarma, R. Schlitzer, R. Sieger, I. Skjelvan, T. Steinhoff, K. F. Sullivan, H. Sun, A. J. Sutton, T. Suzuki, C. Sweeney, T. Takahashi, J. Tjiputra, N. Tsurushima, S. M. A. C. van Heuven, D. Vandemark, P. Vlahos, D. W. R. Wallace, R. Wanninkhof, and A. J. Watson
Earth Syst. Sci. Data, 6, 69–90, https://doi.org/10.5194/essd-6-69-2014, https://doi.org/10.5194/essd-6-69-2014, 2014
D. L. Arévalo-Martínez, M. Beyer, M. Krumbholz, I. Piller, A. Kock, T. Steinhoff, A. Körtzinger, and H. W. Bange
Ocean Sci., 9, 1071–1087, https://doi.org/10.5194/os-9-1071-2013, https://doi.org/10.5194/os-9-1071-2013, 2013
P. J. Llanillo, J. Karstensen, J. L. Pelegrí, and L. Stramma
Biogeosciences, 10, 6339–6355, https://doi.org/10.5194/bg-10-6339-2013, https://doi.org/10.5194/bg-10-6339-2013, 2013
T. Fischer, D. Banyte, P. Brandt, M. Dengler, G. Krahmann, T. Tanhua, and M. Visbeck
Biogeosciences, 10, 5079–5093, https://doi.org/10.5194/bg-10-5079-2013, https://doi.org/10.5194/bg-10-5079-2013, 2013
W. Cheah, B. B. Taylor, S. Wiegmann, S. Raimund, G. Krahmann, B. Quack, and A. Bracher
Biogeosciences Discuss., https://doi.org/10.5194/bgd-10-12115-2013, https://doi.org/10.5194/bgd-10-12115-2013, 2013
Revised manuscript not accepted
Related subject area
Biogeophysics: Physical - Biological Coupling
Abundance and viability of particle-attached and free-floating bacteria in dusty and nondusty air
Linking tundra vegetation, snow, soil temperature, and permafrost
Drivers of the spatial phytoplankton gradient in estuarine–coastal systems: generic implications of a case study in a Dutch tidal bay
Biological and biogeochemical methods for estimating bioirrigation: a case study in the Oosterschelde estuary
Evidence of eddy-related deep ocean current variability in the North-East Tropical Pacific Ocean induced by remote gap winds
Dissolved inorganic nitrogen and particulate organic nitrogen budget in the Yucatán shelf: driving mechanisms through a physical–biogeochemical coupled model
Bacterial and fungal predator – prey interactions modulate soil aggregation
Basal thermal regime affects the biogeochemistry of subglacial systems
Influence of oceanic conditions in the energy transfer efficiency estimation of a micronekton model
Interactive impacts of meteorological and hydrological conditions on the physical and biogeochemical structure of a coastal system
Modulation of the North Atlantic deoxygenation by the slowdown of the nutrient stream
Stand age and species composition effects on surface albedo in a mixedwood boreal forest
Assessing the peatland hummock–hollow classification framework using high-resolution elevation models: implications for appropriate complexity ecosystem modeling
Tidal and seasonal forcing of dissolved nutrient fluxes in reef communities
Ideas and perspectives: Development of nascent autotrophic carbon fixation systems in various redox conditions of the fluid degassing on early Earth
Vertical distribution of chlorophyll in dynamically distinct regions of the southern Bay of Bengal
Remote and local drivers of oxygen and nitrate variability in the shallow oxygen minimum zone off Mauritania in June 2014
Longitudinal contrast in turbulence along a ∼ 19° S section in the Pacific and its consequences for biogeochemical fluxes
Ideas and perspectives: Strengthening the biogeosciences in environmental research networks
Imprint of Southern Ocean mesoscale eddies on chlorophyll
Grazing increases litter decomposition rate but decreases nitrogen release rate in an alpine meadow
Large- to submesoscale surface circulation and its implications on biogeochemical/biological horizontal distributions during the OUTPACE cruise (southwest Pacific)
OUTPACE long duration stations: physical variability, context of biogeochemical sampling, and evaluation of sampling strategy
Reviews and syntheses: on the roles trees play in building and plumbing the critical zone
Effects of shrub and tree cover increase on the near-surface atmosphere in northern Fennoscandia
Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize
Amplification of global warming through pH dependence of DMS production simulated with a fully coupled Earth system model
Physical control of interannual variations of the winter chlorophyll bloom in the northern Arabian Sea
Tree growth and its climate signal along latitudinal and altitudinal gradients: comparison of tree rings between Finland and the Tibetan Plateau
Biogeochemical versus ecological consequences of modeled ocean physics
Analytical solution of the nitracline with the evolution of subsurface chlorophyll maximum in stratified water columns
Upwelling and isolation in oxygen-depleted anticyclonic modewater eddies and implications for nitrate cycling
Positive Indian Ocean Dipole events prevent anoxia off the west coast of India
Linking diverse nutrient patterns to different water masses within anticyclonic eddies in the upwelling system off Peru
Can terrestrial laser scanners (TLSs) and hemispherical photographs predict tropical dry forest succession with liana abundance?
Multi-frequency electrical impedance tomography as a non-invasive tool to characterize and monitor crop root systems
The growth of shrubs on high Arctic tundra at Bylot Island: impact on snow physical properties and permafrost thermal regime
Linking the distribution of microbial deposits from the Great Salt Lake (Utah, USA) to tectonic and climatic processes
Physical and biogeochemical spatial scales of variability in the East Australian Current separation from shelf glider measurements
The influence of warm-season precipitation on the diel cycle of the surface energy balance and carbon dioxide at a Colorado subalpine forest site
New insights into the organic carbon export in the Mediterranean Sea from 3-D modeling
Wind-driven interannual variability of sea ice algal production in the western Arctic Chukchi Borderland
Growth response of temperate mountain grasslands to inter-annual variations in snow cover duration
Sensitivity of the regional European boreal climate to changes in surface properties resulting from structural vegetation perturbations
Modeling forest lines and forest distribution patterns with remote-sensing data in a mountainous region of semiarid central Asia
Diatom flux reflects water-mass conditions on the southern Northwind Abyssal Plain, Arctic Ocean
Steady-state solutions for subsurface chlorophyll maximum in stratified water columns with a bell-shaped vertical profile of chlorophyll
Wind-induced upwelling in the Kerguelen Plateau region
Disentangling the response of forest and grassland energy exchange to heatwaves under idealized land–atmosphere coupling
Surface circulation and upwelling patterns around Sri Lanka
Wei Hu, Kotaro Murata, Chunlan Fan, Shu Huang, Hiromi Matsusaki, Pingqing Fu, and Daizhou Zhang
Biogeosciences, 17, 4477–4487, https://doi.org/10.5194/bg-17-4477-2020, https://doi.org/10.5194/bg-17-4477-2020, 2020
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This paper reports the first estimate of the status of bacteria in long-distance-transported Asian dust, demonstrating that airborne dust, which can carry viable and nonviable bacteria on particle surfaces, is an efficient medium for constantly spreading bacteria at regional and even global scales. Such data are essential to better model and understand the roles and activities of bioaerosols in environmental evolution and climate change and the potential risks of bioaerosols to human health.
Inge Grünberg, Evan J. Wilcox, Simon Zwieback, Philip Marsh, and Julia Boike
Biogeosciences, 17, 4261–4279, https://doi.org/10.5194/bg-17-4261-2020, https://doi.org/10.5194/bg-17-4261-2020, 2020
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Based on topsoil temperature data for different vegetation types at a low Arctic tundra site, we found large small-scale variability. Winter temperatures were strongly influenced by vegetation through its effects on snow. Summer temperatures were similar below most vegetation types and not consistently related to late summer permafrost thaw depth. Given that vegetation type defines the relationship between winter and summer soil temperature and thaw depth, it controls permafrost vulnerability.
Long Jiang, Theo Gerkema, Jacco C. Kromkamp, Daphne van der Wal, Pedro Manuel Carrasco De La Cruz, and Karline Soetaert
Biogeosciences, 17, 4135–4152, https://doi.org/10.5194/bg-17-4135-2020, https://doi.org/10.5194/bg-17-4135-2020, 2020
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A seaward increasing chlorophyll-a gradient is observed during the spring bloom in a Dutch tidal bay. Biophysical model runs indicate the roles of bivalve grazing and tidal import in shaping the gradient. Five common spatial phytoplankton patterns are summarized in global estuarine–coastal ecosystems: seaward increasing, seaward decreasing, concave with a chlorophyll maximum, weak spatial gradients, and irregular patterns.
Emil De Borger, Justin Tiano, Ulrike Braeckman, Tom Ysebaert, and Karline Soetaert
Biogeosciences, 17, 1701–1715, https://doi.org/10.5194/bg-17-1701-2020, https://doi.org/10.5194/bg-17-1701-2020, 2020
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By applying a novel technique to quantify organism-induced sediment–water column fluid exchange (bioirrigation), we show that organisms in subtidal (permanently submerged) areas have similar bioirrigation rates as those that inhabit intertidal areas (not permanently submerged), but organisms in the latter irrigate deeper burrows in this study. Our results expand on traditional methods to quantify bioirrigation rates and broaden the pool of field measurements of bioirrigation rates.
Kaveh Purkiani, André Paul, Annemiek Vink, Maren Walter, Michael Schulz, and Matthias Haeckel
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-77, https://doi.org/10.5194/bg-2020-77, 2020
Revised manuscript accepted for BG
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There has been a steady increase of interest in mining of deep-sea minerals in the eastern Pacific Ocean recently. The ocean state in this region is known to be highly influenced by rotating body of water (eddies) which some of them can travel long distances in the ocean and impact the deeper layers of the ocean. A better insight of variability of eddy activity in this region is of great help to mitigate the impact of the benthic ecosystem from future potential deep sea mining activity.
Sheila N. Estrada-Allis, Julio Sheinbaum Pardo, Joao M. Azevedo Correia de Souza, Cecilia Elizabeth Enríquez Ortiz, Ismael Mariño Tapia, and Jorge A. Herrera-Silveira
Biogeosciences, 17, 1087–1111, https://doi.org/10.5194/bg-17-1087-2020, https://doi.org/10.5194/bg-17-1087-2020, 2020
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Continental shelves are the most productive areas in the ocean and can have an important impact on the nutrient cycle as well as the climate system. The one in Yucatán is the largest shelf in the Gulf of Mexico. However, its nutrient budget remains unidentifiable. Here we propose not only a general nutrient budget for the Yucatán Shelf but also the physical processes responsible for its pathway modulation through a physical–biogeochemical coupled model of the whole Gulf of Mexico.
Amandine Erktan, Matthias C. Rillig, Andrea Carminati, Alexandre Jousset, and Stefan Scheu
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-48, https://doi.org/10.5194/bg-2020-48, 2020
Revised manuscript accepted for BG
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Soil aggregation is crucial for protecting soils from erosion, a major worldwide threat. While the role of bacteria and fungi in soil aggregation is well established, how predators feeding on microbes modify soil aggregation has hardly been investigated. We showed for the first time that protists modify soil aggregation, presumably through changes in the production of bacterial mucilage, and that collembolans reduce soil aggregation, presumably by reducing the abundance of saproptrophic fungi.
Ashley Dubnick, Martin Sharp, Brad Danielson, Alireza Saidi-Mehrabad, and Joel Barker
Biogeosciences, 17, 963–977, https://doi.org/10.5194/bg-17-963-2020, https://doi.org/10.5194/bg-17-963-2020, 2020
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We found that glaciers with basal temperatures near the melting point mobilize more solutes, nutrients, and microbes from the underlying substrate and are more likely to promote in situ biogeochemical activity than glaciers with basal temperatures well below the melting point. The temperature at the base of glaciers is therefore an important control on the biogeochemistry of ice near glacier beds, and, ultimately, the potential solutes, nutrients, and microbes exported from glaciated watersheds.
Audrey Delpech, Anna Conchon, Olivier Titaud, and Patrick Lehodey
Biogeosciences, 17, 833–850, https://doi.org/10.5194/bg-17-833-2020, https://doi.org/10.5194/bg-17-833-2020, 2020
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Micronekton is an important, yet poorly known, component of the trophic chain, which partly contributes to the storage of CO2 in the deep ocean thanks to biomass vertical migrations. In this study, we characterize the ideal sampling regions to estimate the amount of biomass that undergoes theses migrations. We find that observations made in warm, nondynamic and productive waters reduce the error of the estimation by 20 %. This result should likely serve for future in situ network deployment.
Onur Kerimoglu, Yoana G. Voynova, Fatemeh Chegini, Holger Brix, Ulrich Callies, Richard Hofmeister, Knut Klingbeil, Corinna Schrum, and Justus E. E. van Beusekom
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-1, https://doi.org/10.5194/bg-2020-1, 2020
Revised manuscript accepted for BG
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In this study, using extensive field observations and a numerical model, we analyzed the physical and biogeochemical structure of a coastal system following an extreme flood event. Our results suggest that a number of anomalous observations were driven by a co-occurrence of peculiar meteorological conditions and increased riverine discharges. Our results call for attention to the combined effects of hydrological and meteorological extremes that are anticipated to increase in frequency.
Filippos Tagklis, Takamitsu Ito, and Annalisa Bracco
Biogeosciences, 17, 231–244, https://doi.org/10.5194/bg-17-231-2020, https://doi.org/10.5194/bg-17-231-2020, 2020
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Deoxygenation of the oceans is potentially one of the most severe ecosystem stressors resulting from global warming given the high sensitivity of dissolved oxygen to ocean temperatures. Climate models suggest that despite the thermodynamic tendency of the oceans to lose oxygen, certain regions experience significant changes in the biologically driven O2 consumption, resulting in a resistance against deoxygenation. Overturning circulation changes are responsible for such a behavior.
Mohammad Abdul Halim, Han Y. H. Chen, and Sean C. Thomas
Biogeosciences, 16, 4357–4375, https://doi.org/10.5194/bg-16-4357-2019, https://doi.org/10.5194/bg-16-4357-2019, 2019
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Using field data collected over 4 years across a range of stand ages, we investigated how seasonal surface albedo in boreal forest varies with stand age, stand structure, and composition. Our results indicate that successional change in species composition is a key driver of age–related patterns in albedo, with hardwood species associated with higher albedo. The patterns described have important implications for both climate modeling and
climate–smartboreal forest management.
Paul A. Moore, Maxwell C. Lukenbach, Dan K. Thompson, Nick Kettridge, Gustaf Granath, and James M. Waddington
Biogeosciences, 16, 3491–3506, https://doi.org/10.5194/bg-16-3491-2019, https://doi.org/10.5194/bg-16-3491-2019, 2019
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Using very-high-resolution digital elevation models (DEMs), we assessed the basic structure and microtopographic variability of hummock–hollow plots at boreal and hemi-boreal sites primarily in North America. Using a simple model of peatland biogeochemical function, our results suggest that both surface heating and moss productivity may not be adequately resolved in models which only consider idealized hummock–hollow units.
Renee K. Gruber, Ryan J. Lowe, and James L. Falter
Biogeosciences, 16, 1921–1935, https://doi.org/10.5194/bg-16-1921-2019, https://doi.org/10.5194/bg-16-1921-2019, 2019
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Researchers from the University of Western Australia's Oceans Institute are studying large tides (up to 12 m range) that occur in the Kimberley region of Australia. These tides flush coral reefs with water rich in nutrients, which supports the growth of reef organisms. In this paper, we show how tidal cycles and seasons control nutrient availability on reefs. This study is among the first published accounts of reefs and water quality data in the remote and pristine Kimberley region.
Sergey A. Marakushev and Ol'ga V. Belonogova
Biogeosciences, 16, 1817–1828, https://doi.org/10.5194/bg-16-1817-2019, https://doi.org/10.5194/bg-16-1817-2019, 2019
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Among the existing theories of the autotrophic origin of life, CO2 is usually considered to be the carbon source for nascent autotrophic metabolism. However, ancestral carbon used in metabolism may have been derived from CH4 if the outflow of magma fluid to the surface of the Earth consisted mainly of methane. The hydrothermal system model is considered in the form of a phase diagram, which demonstrates the area of redox and P and T conditions favorable to development of primary methanotroph.
Venugopal Thushara, Puthenveettil Narayana Menon Vinayachandran, Adrian J. Matthews, Benjamin G. M. Webber, and Bastien Y. Queste
Biogeosciences, 16, 1447–1468, https://doi.org/10.5194/bg-16-1447-2019, https://doi.org/10.5194/bg-16-1447-2019, 2019
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Chlorophyll distribution in the ocean remains to be explored in detail, despite its climatic significance. Here, we document the vertical structure of chlorophyll in the Bay of Bengal using observations and a model. The shape of chlorophyll profiles, characterized by prominent deep chlorophyll maxima, varies in dynamically different regions, controlled by the monsoonal forcings. The present study provides new insights into the vertical distribution of chlorophyll, rarely observed by satellites.
Soeren Thomsen, Johannes Karstensen, Rainer Kiko, Gerd Krahmann, Marcus Dengler, and Anja Engel
Biogeosciences, 16, 979–998, https://doi.org/10.5194/bg-16-979-2019, https://doi.org/10.5194/bg-16-979-2019, 2019
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Physical and biogeochemical observations from an autonomous underwater vehicle in combination with ship-based measurements are used to investigate remote and local drivers of the oxygen and nutrient variability off Mauritania. Beside the transport of oxygen and nutrients characteristics from remote areas towards Mauritania also local remineralization of organic material close to the seabed seems to be important for the distribution of oxygen and nutrients.
Pascale Bouruet-Aubertot, Yannis Cuypers, Andrea Doglioli, Mathieu Caffin, Christophe Yohia, Alain de Verneil, Anne Petrenko, Dominique Lefèvre, Hervé Le Goff, Gilles Rougier, Marc Picheral, and Thierry Moutin
Biogeosciences, 15, 7485–7504, https://doi.org/10.5194/bg-15-7485-2018, https://doi.org/10.5194/bg-15-7485-2018, 2018
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The OUTPACE cruise took place between New Caledonia and French Polynesia. The main purpose was to understand how micro-organisms can survive in a very poor environment. One main source of nutrients is at depth, below the euphotic layer where micro-organisms live. The purpose of the turbulence measurements was to determine to which extent turbulence may
upliftnutrients into the euphotic layer. The origin of the turbulence that was found contrasted along the transect was also determined.
Daniel D. Richter, Sharon A. Billings, Peter M. Groffman, Eugene F. Kelly, Kathleen A. Lohse, William H. McDowell, Timothy S. White, Suzanne Anderson, Dennis D. Baldocchi, Steve Banwart, Susan Brantley, Jean J. Braun, Zachary S. Brecheisen, Charles W. Cook, Hilairy E. Hartnett, Sarah E. Hobbie, Jerome Gaillardet, Esteban Jobbagy, Hermann F. Jungkunst, Clare E. Kazanski, Jagdish Krishnaswamy, Daniel Markewitz, Katherine O'Neill, Clifford S. Riebe, Paul Schroeder, Christina Siebe, Whendee L. Silver, Aaron Thompson, Anne Verhoef, and Ganlin Zhang
Biogeosciences, 15, 4815–4832, https://doi.org/10.5194/bg-15-4815-2018, https://doi.org/10.5194/bg-15-4815-2018, 2018
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As knowledge in biology and geology explodes, science becomes increasingly specialized. Given the overlap of the environmental sciences, however, the explosion in knowledge inevitably creates opportunities for interconnecting the biogeosciences. Here, 30 scientists emphasize the opportunities for biogeoscience collaborations across the world’s remarkable long-term environmental research networks that can advance science and engage larger scientific and public audiences.
Ivy Frenger, Matthias Münnich, and Nicolas Gruber
Biogeosciences, 15, 4781–4798, https://doi.org/10.5194/bg-15-4781-2018, https://doi.org/10.5194/bg-15-4781-2018, 2018
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Although mesoscale ocean eddies are ubiquitous in the Southern Ocean (SO), their regional and seasonal association with phytoplankton has not been quantified. We identify over 100 000 eddies and determine the associated phytoplankton biomass anomalies using satellite-based chlorophyll (Chl) as a proxy. The emerging Chl anomalies can be explained largely by lateral advection of Chl by eddies. This impact of eddies on phytoplankton may implicate downstream effects on SO biogeochemical properties.
Yi Sun, Xiong Z. He, Fujiang Hou, Zhaofeng Wang, and Shenghua Chang
Biogeosciences, 15, 4233–4243, https://doi.org/10.5194/bg-15-4233-2018, https://doi.org/10.5194/bg-15-4233-2018, 2018
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To investigate how grazing alters litter composition, quality and decomposition, we collected litter from grazing (GP) and grazing exclusion paddocks (GEP) and incubated them in situ and across sites. Grazing increased litter N and grazing exclusion increased litter mass of palatable species and promoted SOC. Litter decomposed faster in GP and N was opposite. Site environment had more impact on litter decomposition. Results may be helpful in developing strategies to restore degraded grasslands.
Louise Rousselet, Alain de Verneil, Andrea M. Doglioli, Anne A. Petrenko, Solange Duhamel, Christophe Maes, and Bruno Blanke
Biogeosciences, 15, 2411–2431, https://doi.org/10.5194/bg-15-2411-2018, https://doi.org/10.5194/bg-15-2411-2018, 2018
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The patterns of the large- and fine-scale surface circulation on biogeochemical and biological distributions are examined in the western tropical South Pacific (WTSP) in the context of the OUTPACE oceanographic cruise. The combined use of in situ and satellite data allows for the identification of water mass transport pathways and fine-scale structures, such as fronts, that drive surface distribution of tracers and microbial community structures.
Alain de Verneil, Louise Rousselet, Andrea M. Doglioli, Anne A. Petrenko, Christophe Maes, Pascale Bouruet-Aubertot, and Thierry Moutin
Biogeosciences, 15, 2125–2147, https://doi.org/10.5194/bg-15-2125-2018, https://doi.org/10.5194/bg-15-2125-2018, 2018
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Oceanographic campaigns to measure biogeochemical processes popularly deploy drifters with onboard incubations to stay in a single body of water. Here, we aggregate physical data taken during such a cruise, OUTPACE, to independently test in a new approach whether the drifter really stayed in what can be considered a single biological or chemical environment. This study concludes that future campaigns would benefit from similar data collection and analysis to validate their sampling strategy.
Susan L. Brantley, David M. Eissenstat, Jill A. Marshall, Sarah E. Godsey, Zsuzsanna Balogh-Brunstad, Diana L. Karwan, Shirley A. Papuga, Joshua Roering, Todd E. Dawson, Jaivime Evaristo, Oliver Chadwick, Jeffrey J. McDonnell, and Kathleen C. Weathers
Biogeosciences, 14, 5115–5142, https://doi.org/10.5194/bg-14-5115-2017, https://doi.org/10.5194/bg-14-5115-2017, 2017
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This review represents the outcome from an invigorating workshop discussion that involved tree physiologists, geomorphologists, ecologists, geochemists, and hydrologists and developed nine hypotheses that could be tested. We argue these hypotheses point to the essence of issues we must explore if we are to understand how the natural system of the earth surface evolves, and how humans will affect its evolution. This paper will create discussion and interest both before and after publication.
Johanne H. Rydsaa, Frode Stordal, Anders Bryn, and Lena M. Tallaksen
Biogeosciences, 14, 4209–4227, https://doi.org/10.5194/bg-14-4209-2017, https://doi.org/10.5194/bg-14-4209-2017, 2017
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We investigate the atmospheric sensitivity to an expansion in shrub and tree cover in the northern Fennoscandia region. We applied a regional weather and climate model in evaluating biophysical effects of increased shrub cover at a fine resolution. We find that shrub cover increase causes a warming that is sensitive to the shrub and tree heights. Cooling effects include increased snow cover, cloud cover, and precipitation. We show that the net warming will likely increase in the future.
Qian Cai, Yulong Zhang, Zhanxiang Sun, Jiaming Zheng, Wei Bai, Yue Zhang, Yang Liu, Liangshan Feng, Chen Feng, Zhe Zhang, Ning Yang, Jochem B. Evers, and Lizhen Zhang
Biogeosciences, 14, 3851–3858, https://doi.org/10.5194/bg-14-3851-2017, https://doi.org/10.5194/bg-14-3851-2017, 2017
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Large yield gaps exist in rain-fed maize in semi-arid regions caused by frequent droughts halfway through the growing period due to uneven distribution of rainfall. It can be questioned whether irrigation systems are economically and ecologically required. Maize yield was not affected by mild water stress due to the morphological plasticity in root growth. Our results help to mitigate drought risk in dry-land agriculture.
Jörg Schwinger, Jerry Tjiputra, Nadine Goris, Katharina D. Six, Alf Kirkevåg, Øyvind Seland, Christoph Heinze, and Tatiana Ilyina
Biogeosciences, 14, 3633–3648, https://doi.org/10.5194/bg-14-3633-2017, https://doi.org/10.5194/bg-14-3633-2017, 2017
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Transient global warming under the high emission scenario RCP8.5 is amplified by up to 6 % if a pH dependency of marine DMS production is assumed. Importantly, this additional warming is not spatially homogeneous but shows a pronounced north–south gradient. Over the Antarctic continent, the additional warming is almost twice the global average. In the Southern Ocean we find a small DMS–climate feedback that counteracts the original reduction of DMS production due to ocean acidification.
Madhavan Girijakumari Keerthi, Matthieu Lengaigne, Marina Levy, Jerome Vialard, Vallivattathillam Parvathi, Clément de Boyer Montégut, Christian Ethé, Olivier Aumont, Iyyappan Suresh, Valiya Parambil Akhil, and Pillathu Moolayil Muraleedharan
Biogeosciences, 14, 3615–3632, https://doi.org/10.5194/bg-14-3615-2017, https://doi.org/10.5194/bg-14-3615-2017, 2017
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The northern Arabian Sea hosts a winter chlorophyll bloom, which exhibits strong interannual variability. The processes responsible for this interannual variation of the bloom are investigated using observations and a model. The interannual fluctuations of the winter bloom are largely related to the interannual mixed-layer depth (MLD) anomalies, which are driven by net heat flux anomalies. MLD controls the bloom amplitude through a modulation of nutrient turbulent fluxes into the mixed layer.
Lixin Lyu, Susanne Suvanto, Pekka Nöjd, Helena M. Henttonen, Harri Mäkinen, and Qi-Bin Zhang
Biogeosciences, 14, 3083–3095, https://doi.org/10.5194/bg-14-3083-2017, https://doi.org/10.5194/bg-14-3083-2017, 2017
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Our results reveal that the change in the tree growth–climate relationship is similar along latitudinal and altitudinal gradients, especially during growing seasons. Moreover, the critical periods for climatic effects on tree radial growth occurred earlier at lower latitudes and altitudes than at the cold ends of the gradients. We further demonstrate the use of daily climate data, as they may disclose more precise gradient patterns that could not be detected if monthly climate data were used.
Sophie Clayton, Stephanie Dutkiewicz, Oliver Jahn, Christopher Hill, Patrick Heimbach, and Michael J. Follows
Biogeosciences, 14, 2877–2889, https://doi.org/10.5194/bg-14-2877-2017, https://doi.org/10.5194/bg-14-2877-2017, 2017
Xiang Gong, Wensheng Jiang, Linhui Wang, Huiwang Gao, Emmanuel Boss, Xiaohong Yao, Shuh-Ji Kao, and Jie Shi
Biogeosciences, 14, 2371–2386, https://doi.org/10.5194/bg-14-2371-2017, https://doi.org/10.5194/bg-14-2371-2017, 2017
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The subsurface chlorophyll maximum layer (SCML) forms near the nitracline. By incorporating a piecewise function for the approximate Gaussian vertical profile of chlorophyll, we derive analytical solutions of a specified nutrient–phytoplankton model. Nitracline depth is deeper than SCML depth, and a thinner SCML corresponds to a steeper nitracline. A higher light attenuation coefficient leads to a shallower but steeper nitracline. Nitracline steepness is independent of surface light intensity.
Johannes Karstensen, Florian Schütte, Alice Pietri, Gerd Krahmann, Björn Fiedler, Damian Grundle, Helena Hauss, Arne Körtzinger, Carolin R. Löscher, Pierre Testor, Nuno Vieira, and Martin Visbeck
Biogeosciences, 14, 2167–2181, https://doi.org/10.5194/bg-14-2167-2017, https://doi.org/10.5194/bg-14-2167-2017, 2017
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High-resolution observational data from underwater gliders and ships are used to investigate drivers and pathways of nutrient upwelling in high-productive whirling ecosystems (eddies). The data suggest that the upwelling is created by the interaction of wind-induced internal waves with the local rotation of the eddy. Because of differences in nutrient and oxygen pathways, a low-oxygen core is established at shallow depth in the high-productive eddies.
Parvathi Vallivattathillam, Suresh Iyyappan, Matthieu Lengaigne, Christian Ethé, Jérôme Vialard, Marina Levy, Neetu Suresh, Olivier Aumont, Laure Resplandy, Hema Naik, and Wajih Naqvi
Biogeosciences, 14, 1541–1559, https://doi.org/10.5194/bg-14-1541-2017, https://doi.org/10.5194/bg-14-1541-2017, 2017
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During late boreal summer and fall, the west coast of India (WCI) experiences hypoxia, which turns into anoxia during some years. We analyze a coupled physical–biogeochemical simulation over the 1960–2012 period to investigate the physical processes influencing oxycline interannual variability off the WCI. We show that fall WCI oxycline fluctuations are strongly related to Indian Ocean Dipole (IOD), with positive IODs preventing anoxia, while negative IODs do not necessarily result in anoxia.
Yonss Saranga José, Heiner Dietze, and Andreas Oschlies
Biogeosciences, 14, 1349–1364, https://doi.org/10.5194/bg-14-1349-2017, https://doi.org/10.5194/bg-14-1349-2017, 2017
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This study aims to investigate the diverse subsurface nutrient patterns observed within anticyclonic eddies in the upwelling system off Peru. Two simulated anticyclonic eddies with opposing subsurface nitrate concentrations were analysed. The results show that diverse nutrient patterns within anticyclonic eddies are related to the presence of water mass from different origins at different depths, responding to variations in depth of the circulation strength at the edge of the eddy.
Gerardo Arturo Sánchez-Azofeifa, J. Antonio Guzmán-Quesada, Mauricio Vega-Araya, Carlos Campos-Vargas, Sandra Milena Durán, Nikhil D'Souza, Thomas Gianoli, Carlos Portillo-Quintero, and Iain Sharp
Biogeosciences, 14, 977–988, https://doi.org/10.5194/bg-14-977-2017, https://doi.org/10.5194/bg-14-977-2017, 2017
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Lianas (woody vines) tend to respond positively to disturbance and show high densities in secondary forests. Lianas are a key component of tropical forests because they may reduce carbon potential. Identifying tools for liana detection is therefore essential for monitoring changes in tropical forests. In this study, we describe how terrestrial laser scanning can be used to detect the presence of lianas in forest stands of different ages in secondary tropical dry forests at a regional scale.
Maximilian Weigand and Andreas Kemna
Biogeosciences, 14, 921–939, https://doi.org/10.5194/bg-14-921-2017, https://doi.org/10.5194/bg-14-921-2017, 2017
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Root systems are essential in nutrient uptake and translocation, but are difficult to characterize non-invasively with existing methods. We propose electrical impedance tomography (EIT) as a new tool for the imaging and monitoring of crop root systems. In a laboratory experiment we demonstrate the capability of the method to capture physiological responses of root systems with high spatial and temporal resolution. We conclude that EIT is a promising functional imaging technique for crop roots.
Florent Domine, Mathieu Barrere, and Samuel Morin
Biogeosciences, 13, 6471–6486, https://doi.org/10.5194/bg-13-6471-2016, https://doi.org/10.5194/bg-13-6471-2016, 2016
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Warming-induced shrub growth in the Arctic traps snow and modifies snow properties, hence the permafrost thermal regime. In the Canadian high Arctic, we measured snow physical properties in the presence and absence of willow shrubs (Salix richardsonii). Shrubs dramatically reduce snow density and thermal conductivity, seriously limiting soil winter cooling. Simulations taking into account only winter changes show that shrub growth leads to a ground winter warming of up to 13 °C.
Anthony Bouton, Emmanuelle Vennin, Julien Boulle, Aurélie Pace, Raphaël Bourillot, Christophe Thomazo, Arnaud Brayard, Guy Désaubliaux, Tomasz Goslar, Yusuke Yokoyama, Christophe Dupraz, and Pieter T. Visscher
Biogeosciences, 13, 5511–5526, https://doi.org/10.5194/bg-13-5511-2016, https://doi.org/10.5194/bg-13-5511-2016, 2016
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The modern hypersaline Great Salt Lake shows an extended modern and ancient microbial sedimentary system. This study on aerial images and field observations discusses the non-random distribution patterns of microbial deposits along linear alignments following isobaths, polygonal geometry or straight alignments along a topographic drop-off. This particular distribution of microbial deposits brings further insights to the reconstruction of paleoenvironments and paleoclimatic changes.
Amandine Schaeffer, Moninya Roughan, Emlyn M. Jones, and Dana White
Biogeosciences, 13, 1967–1975, https://doi.org/10.5194/bg-13-1967-2016, https://doi.org/10.5194/bg-13-1967-2016, 2016
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The water properties of the coastal ocean such as temperature, salt, oxygen, or chlorophyll content vary spatially, and estimates need to be made regarding the scales of variability. Here, we use statistical techniques to determine the spatial variability of ocean properties from high-resolution measurements by gliders. We show that biological activity is patchy compared to the distribution of physical characteristics, and that the size and shape of this is determined by coastal ocean processes.
S. P. Burns, P. D. Blanken, A. A. Turnipseed, J. Hu, and R. K. Monson
Biogeosciences, 12, 7349–7377, https://doi.org/10.5194/bg-12-7349-2015, https://doi.org/10.5194/bg-12-7349-2015, 2015
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The effect of warm-season precipitation on
environmental conditions and ecosystem-scale fluxes at a
high-elevation subalpine forest site was investigated. As would be
expected (based on the surface energy balance), precipitation caused
an increase in latent heat flux (evapotranspiration) and a decrease in
sensible heat flux. The evaporative component of evapotranspiration
was, on average, estimated to be around 6% in dry conditions and
between 15-25% in partially wet conditions.
A. Guyennon, M. Baklouti, F. Diaz, J. Palmieri, J. Beuvier, C. Lebaupin-Brossier, T. Arsouze, K. Béranger, J.-C. Dutay, and T. Moutin
Biogeosciences, 12, 7025–7046, https://doi.org/10.5194/bg-12-7025-2015, https://doi.org/10.5194/bg-12-7025-2015, 2015
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Dissolved organic carbon (DOC) has already been identified as a potentially significant source of carbon export in the Mediterranean Sea, though in situ export estimations are scarce. This work provides a thorough analysis at basin scale of carbon export with the coupled model NEMO-MED12/Eco3M-MED model. The seasonality and the processes of particulate and dissolved carbon production are also investigated. DOC export appears to be dominant in most regions, especially in the eastern basin.
E. Watanabe, J. Onodera, N. Harada, M. N. Aita, A. Ishida, and M. J. Kishi
Biogeosciences, 12, 6147–6168, https://doi.org/10.5194/bg-12-6147-2015, https://doi.org/10.5194/bg-12-6147-2015, 2015
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The current paper presented findings on seasonal and interannual variability of sea ice algal production and biomass over the western Arctic Chukchi Boderland using a pan-Arctic sea ice-ocean modeling approach. In particular, the relationship with wind pattern was focused on. Coupling of physical and biogeochemical analyses provided originality of this study.
P. Choler
Biogeosciences, 12, 3885–3897, https://doi.org/10.5194/bg-12-3885-2015, https://doi.org/10.5194/bg-12-3885-2015, 2015
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It is shown that inter-annual variations in the primary productivity of mountain grasslands are primarily governed by variations in the length of the snow-free period and to a much lesser extent by temperature and precipitation during the growing season. Meteorological variables controlling snow cover dynamics are thus of paramount importance to understand and model the amount and timing of biomass production in mountain pastures.
J. H. Rydsaa, F. Stordal, and L. M. Tallaksen
Biogeosciences, 12, 3071–3087, https://doi.org/10.5194/bg-12-3071-2015, https://doi.org/10.5194/bg-12-3071-2015, 2015
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MODIS land surface data with WRF V3.5.1 and Noah LSM is used to investigate the sensitivity of the atmosphere to changes in structural vegetation in the boreal ecosystem. Results show that high north evergreen forest expansion leads to larger latent heat fluxes, while increased summer precipitation and reduced wind speed lead to lower sensible heat flux. Replacement of evergreen forest with mixed forest have largely opposite effects, moderating the regional effects on the atmosphere.
M. Klinge, J. Böhner, and S. Erasmi
Biogeosciences, 12, 2893–2905, https://doi.org/10.5194/bg-12-2893-2015, https://doi.org/10.5194/bg-12-2893-2015, 2015
J. Onodera, E. Watanabe, N. Harada, and M. C. Honda
Biogeosciences, 12, 1373–1385, https://doi.org/10.5194/bg-12-1373-2015, https://doi.org/10.5194/bg-12-1373-2015, 2015
X. Gong, J. Shi, H. W. Gao, and X. H. Yao
Biogeosciences, 12, 905–919, https://doi.org/10.5194/bg-12-905-2015, https://doi.org/10.5194/bg-12-905-2015, 2015
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Analytical solutions indicate that subsurface chlorophyll maximum (SCM) occurs at or below the depth of optimal growth of phytoplankton, and the depth of SCM layer deepens logarithmically with an increase in surface light intensity; thickness and intensity of the SCM layer are mainly affected by nutrient supply, but independent of surface light intensity; intensity of the SCM strengthens as a result of this layer being shrunk by a higher light attenuation coefficient or a large sinking velocity
S. T. Gille, M. M. Carranza, R. Cambra, and R. Morrow
Biogeosciences, 11, 6389–6400, https://doi.org/10.5194/bg-11-6389-2014, https://doi.org/10.5194/bg-11-6389-2014, 2014
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The Kerguelen Plateau supports a strong spring chlorophyll bloom, in contrast with most of the Southern Ocean. Throughout the Southern Ocean, including in the Kerguelen area, wind can determine oceanic vertical velocities that may bring nutrients to the surface and contribute to the development of blooms. The Kerguelen Island itself generates a wind shadow that locally enhances upwelling velocities to the north of the main axis of the winds, and chlorophyll is high in this upwelling region.
C. C. van Heerwaarden and A. J. Teuling
Biogeosciences, 11, 6159–6171, https://doi.org/10.5194/bg-11-6159-2014, https://doi.org/10.5194/bg-11-6159-2014, 2014
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This study disentangles the response of forest and grassland to heatwaves, to interpret the findings of Teuling et al. (2010), who found systematically higher temperatures over forests than over grasslands in European heatwaves. By means of a study with a simple coupled land–atmosphere model, we show that the increase in stomatal resistance of vegetation under high values of vapor pressure deficit explains most of the differences and that this increase is enhanced by boundary layer feedbacks.
A. de Vos, C. B. Pattiaratchi, and E. M. S. Wijeratne
Biogeosciences, 11, 5909–5930, https://doi.org/10.5194/bg-11-5909-2014, https://doi.org/10.5194/bg-11-5909-2014, 2014
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Mesoscale eddies with very low–oxygen concentrations at shallow depth have been recently discovered in the eastern tropical North Atlantic. Our analysis shows that low oxygen eddies occur more frequent than expected and are found even close to the equator (8° N). From budget calculations we show that an oxygen reduction of 7 µmol/kg in the depth range of 50–150 m in the eastern tropical North Atlantic (peak reduction is 16 µmol/kg at 100 m depth) can be associated with the dispersion of these eddies.
Mesoscale eddies with very low–oxygen concentrations at shallow depth have been recently...
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