Articles | Volume 18, issue 7
https://doi.org/10.5194/bg-18-2301-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-18-2301-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
09 Apr 2021
Research article |
| 09 Apr 2021
| 09 Apr 2021
Spatial patterns of ectoenzymatic kinetics in relation to biogeochemical properties in the Mediterranean Sea and the concentration of the fluorogenic substrate used
France Van Wambeke
CORRESPONDING AUTHOR
Aix-Marseille Université, CNRS/INSU, Université de Toulon,
IRD, Mediterranean Institute of Oceanography (MIO) UM110, 13288, Marseille,
France
Elvira Pulido
Aix-Marseille Université, CNRS/INSU, Université de Toulon,
IRD, Mediterranean Institute of Oceanography (MIO) UM110, 13288, Marseille,
France
Philippe Catala
Sorbonne Universités, UPMC University Paris 6, Laboratoire
d'Océanographie Microbienne (LOMIC), Observatoire Océanologique,
66650, Banyuls/mer, France
Julie Dinasquet
Marine Biology Research Division, Scripps Institution of Oceanography,
UCSD, La Jolla, CA, USA
Sorbonne Universités, UPMC University Paris 6, Laboratoire
d'Océanographie Microbienne (LOMIC), Observatoire Océanologique,
66650, Banyuls/mer, France
Kahina Djaoudi
Aix-Marseille Université, CNRS/INSU, Université de Toulon,
IRD, Mediterranean Institute of Oceanography (MIO) UM110, 13288, Marseille,
France
Molecular and Cellular Biology, The University of Arizona, Tucson, AZ, USA
Anja Engel
GEOMAR, Helmholtz Centre for Ocean Research, Kiel, Germany
Marc Garel
Aix-Marseille Université, CNRS/INSU, Université de Toulon,
IRD, Mediterranean Institute of Oceanography (MIO) UM110, 13288, Marseille,
France
Sophie Guasco
Aix-Marseille Université, CNRS/INSU, Université de Toulon,
IRD, Mediterranean Institute of Oceanography (MIO) UM110, 13288, Marseille,
France
Barbara Marie
Sorbonne Universités, UPMC University Paris 6, Laboratoire
d'Océanographie Microbienne (LOMIC), Observatoire Océanologique,
66650, Banyuls/mer, France
Sandra Nunige
Aix-Marseille Université, CNRS/INSU, Université de Toulon,
IRD, Mediterranean Institute of Oceanography (MIO) UM110, 13288, Marseille,
France
Vincent Taillandier
CNRS, Sorbonne Universités, Laboratoire d'Océanographie de
Villefranche (LOV), UMR7093, 06230 Villefranche-sur-Mer, France
Birthe Zäncker
CNRS, Sorbonne Universités, Laboratoire d'Océanographie de
Villefranche (LOV), UMR7093, 06230 Villefranche-sur-Mer, France
The Marine Biological Association of the UK, Plymouth, United Kingdom
Christian Tamburini
Aix-Marseille Université, CNRS/INSU, Université de Toulon,
IRD, Mediterranean Institute of Oceanography (MIO) UM110, 13288, Marseille,
France
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Saharan dust deposition of nutrients and trace metals is crucial to microbes in the Mediterranean Sea. Here, we tested the response of microbial and viral communities to simulated dust deposition under present and future conditions of temperature and pH. Overall, the effect of the deposition was dependent on the initial microbial assemblage, and future conditions will intensify microbial responses. We observed effects on trophic interactions, cascading all the way down to viral processes.
Karine Desboeufs, Franck Fu, Matthieu Bressac, Antonio Tovar-Sánchez, Sylvain Triquet, Jean-François Doussin, Chiara Giorio, Patrick Chazette, Julie Disnaquet, Anaïs Feron, Paola Formenti, Franck Maisonneuve, Araceli Rodríguez-Romero, Pascal Zapf, François Dulac, and Cécile Guieu
Atmos. Chem. Phys., 22, 2309–2332, https://doi.org/10.5194/acp-22-2309-2022, https://doi.org/10.5194/acp-22-2309-2022, 2022
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This article reports the first concurrent sampling of wet deposition samples and surface seawater and was performed during the PEACETIME cruise in the remote Mediterranean (May–June 2017). Through the chemical composition of trace metals (TMs) in these samples, it emphasizes the decrease of atmospheric metal pollution in this area during the last few decades and the critical role of wet deposition as source of TMs for Mediterranean surface seawater, especially for intense dust deposition events.
Delaney B. Kilgour, Gordon A. Novak, Jon S. Sauer, Alexia N. Moore, Julie Dinasquet, Sarah Amiri, Emily B. Franklin, Kathryn Mayer, Margaux Winter, Clare K. Morris, Tyler Price, Francesca Malfatti, Daniel R. Crocker, Christopher Lee, Christopher D. Cappa, Allen H. Goldstein, Kimberly A. Prather, and Timothy H. Bertram
Atmos. Chem. Phys., 22, 1601–1613, https://doi.org/10.5194/acp-22-1601-2022, https://doi.org/10.5194/acp-22-1601-2022, 2022
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We report measurements of gas-phase volatile organosulfur molecules made during a mesocosm phytoplankton bloom experiment. Dimethyl sulfide (DMS), methanethiol (MeSH), and benzothiazole accounted for on average over 90 % of total gas-phase sulfur emissions. This work focuses on factors controlling the production and emission of DMS and MeSH and the role of non-DMS molecules (such as MeSH and benzothiazole) in secondary sulfate formation in coastal marine environments.
Céline Ridame, Julie Dinasquet, Søren Hallstrøm, Estelle Bigeard, Lasse Riemann, France Van Wambeke, Matthieu Bressac, Elvira Pulido-Villena, Vincent Taillandier, Fréderic Gazeau, Antonio Tovar-Sanchez, Anne-Claire Baudoux, and Cécile Guieu
Biogeosciences, 19, 415–435, https://doi.org/10.5194/bg-19-415-2022, https://doi.org/10.5194/bg-19-415-2022, 2022
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We show that in the Mediterranean Sea spatial variability in N2 fixation is related to the diazotrophic community composition reflecting different nutrient requirements among species. Nutrient supply by Saharan dust is of great importance to diazotrophs, as shown by the strong stimulation of N2 fixation after a simulated dust event under present and future climate conditions; the magnitude of stimulation depends on the degree of limitation related to the diazotrophic community composition.
Matthieu Bressac, Thibaut Wagener, Nathalie Leblond, Antonio Tovar-Sánchez, Céline Ridame, Vincent Taillandier, Samuel Albani, Sophie Guasco, Aurélie Dufour, Stéphanie H. M. Jacquet, François Dulac, Karine Desboeufs, and Cécile Guieu
Biogeosciences, 18, 6435–6453, https://doi.org/10.5194/bg-18-6435-2021, https://doi.org/10.5194/bg-18-6435-2021, 2021
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Phytoplankton growth is limited by the availability of iron in about 50 % of the ocean. Atmospheric deposition of desert dust represents a key source of iron. Here, we present direct observations of dust deposition in the Mediterranean Sea. A key finding is that the input of iron from dust primarily occurred in the deep ocean, while previous studies mainly focused on the ocean surface. This new insight will enable us to better represent controls on global marine productivity in models.
Stéphanie H. M. Jacquet, Christian Tamburini, Marc Garel, Aurélie Dufour, France Van Vambeke, Frédéric A. C. Le Moigne, Nagib Bhairy, and Sophie Guasco
Biogeosciences, 18, 5891–5902, https://doi.org/10.5194/bg-18-5891-2021, https://doi.org/10.5194/bg-18-5891-2021, 2021
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We compared carbon remineralization rates (MRs) in the western and central Mediterranean Sea in late spring during the PEACETIME cruise, as assessed using the barium tracer. We reported higher and deeper (up to 1000 m depth) MRs in the western basin, potentially sustained by an additional particle export event driven by deep convection. The central basin is the site of a mosaic of blooming and non-blooming water masses and showed lower MRs that were restricted to the upper mesopelagic layer.
Elvira Pulido-Villena, Karine Desboeufs, Kahina Djaoudi, France Van Wambeke, Stéphanie Barrillon, Andrea Doglioli, Anne Petrenko, Vincent Taillandier, Franck Fu, Tiphanie Gaillard, Sophie Guasco, Sandra Nunige, Sylvain Triquet, and Cécile Guieu
Biogeosciences, 18, 5871–5889, https://doi.org/10.5194/bg-18-5871-2021, https://doi.org/10.5194/bg-18-5871-2021, 2021
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We report on phosphorus dynamics in the surface layer of the Mediterranean Sea. Highly sensitive phosphate measurements revealed vertical gradients above the phosphacline. The relative contribution of diapycnal fluxes to total external supply of phosphate to the mixed layer decreased towards the east, where atmospheric deposition dominated. Taken together, external sources of phosphate contributed little to total supply, which was mainly sustained by enzymatic hydrolysis of organic phosphorus.
France Van Wambeke, Vincent Taillandier, Karine Desboeufs, Elvira Pulido-Villena, Julie Dinasquet, Anja Engel, Emilio Marañón, Céline Ridame, and Cécile Guieu
Biogeosciences, 18, 5699–5717, https://doi.org/10.5194/bg-18-5699-2021, https://doi.org/10.5194/bg-18-5699-2021, 2021
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Simultaneous in situ measurements of (dry and wet) atmospheric deposition and biogeochemical stocks and fluxes in the sunlit waters of the open Mediterranean Sea revealed complex physical and biological processes occurring within the mixed layer. Nitrogen (N) budgets were computed to compare the sources and sinks of N in the mixed layer. The transitory effect observed after a wet dust deposition impacted the microbial food web down to the deep chlorophyll maximum.
Frédéric Gazeau, France Van Wambeke, Emilio Marañón, Maria Pérez-Lorenzo, Samir Alliouane, Christian Stolpe, Thierry Blasco, Nathalie Leblond, Birthe Zäncker, Anja Engel, Barbara Marie, Julie Dinasquet, and Cécile Guieu
Biogeosciences, 18, 5423–5446, https://doi.org/10.5194/bg-18-5423-2021, https://doi.org/10.5194/bg-18-5423-2021, 2021
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Our study shows that the impact of dust deposition on primary production depends on the initial composition and metabolic state of the tested community and is constrained by the amount of nutrients added, to sustain both the fast response of heterotrophic prokaryotes and the delayed one of phytoplankton. Under future environmental conditions, heterotrophic metabolism will be more impacted than primary production, therefore reducing the capacity of surface waters to sequester anthropogenic CO2.
Frédéric Gazeau, Céline Ridame, France Van Wambeke, Samir Alliouane, Christian Stolpe, Jean-Olivier Irisson, Sophie Marro, Jean-Michel Grisoni, Guillaume De Liège, Sandra Nunige, Kahina Djaoudi, Elvira Pulido-Villena, Julie Dinasquet, Ingrid Obernosterer, Philippe Catala, and Cécile Guieu
Biogeosciences, 18, 5011–5034, https://doi.org/10.5194/bg-18-5011-2021, https://doi.org/10.5194/bg-18-5011-2021, 2021
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This paper shows that the impacts of Saharan dust deposition in different Mediterranean basins are as strong as those observed in coastal waters but differed substantially between the three tested stations, differences attributed to variable initial metabolic states. A stronger impact of warming and acidification on mineralization suggests a decreased capacity of Mediterranean surface communities to sequester CO2 following the deposition of atmospheric particles in the coming decades.
Evelyn Freney, Karine Sellegri, Alessia Nicosia, Leah R. Williams, Matteo Rinaldi, Jonathan T. Trueblood, André S. H. Prévôt, Melilotus Thyssen, Gérald Grégori, Nils Haëntjens, Julie Dinasquet, Ingrid Obernosterer, France Van Wambeke, Anja Engel, Birthe Zäncker, Karine Desboeufs, Eija Asmi, Hilkka Timonen, and Cécile Guieu
Atmos. Chem. Phys., 21, 10625–10641, https://doi.org/10.5194/acp-21-10625-2021, https://doi.org/10.5194/acp-21-10625-2021, 2021
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In this work, we present observations of the organic aerosol content in primary sea spray aerosols (SSAs) continuously generated along a 5-week cruise in the Mediterranean. This information is combined with seawater biogeochemical properties also measured continuously along the ship track to develop a number of parametrizations that can be used in models to determine SSA organic content in oligotrophic waters that represent 60 % of the oceans from commonly measured seawater variables.
Charlotte M. Beall, Jennifer M. Michaud, Meredith A. Fish, Julie Dinasquet, Gavin C. Cornwell, M. Dale Stokes, Michael D. Burkart, Thomas C. Hill, Paul J. DeMott, and Kimberly A. Prather
Atmos. Chem. Phys., 21, 9031–9045, https://doi.org/10.5194/acp-21-9031-2021, https://doi.org/10.5194/acp-21-9031-2021, 2021
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Ice-nucleating particles (INPs) can influence multiple climate-relevant cloud properties by triggering droplet freezing at relative humidities below or temperatures above the freezing point of water. The ocean is a significant INP source; however, the specific identities of marine INPs remain largely unknown. Here, we identify 14 ice-nucleating microbes from aerosol and precipitation samples collected at a coastal site in southern California, two or more of which are likely marine.
Gerd Krahmann, Damian L. Arévalo-Martínez, Andrew W. Dale, Marcus Dengler, Anja Engel, Nicolaas Glock, Patricia Grasse, Johannes Hahn, Helena Hauss, Mark Hopwood, Rainer Kiko, Alexandra Loginova, Carolin R. Löscher, Marie Maßmig, Alexandra-Sophie Roy, Renato Salvatteci, Stefan Sommer, Toste Tanhua, and Hela Mehrtens
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2020-308, https://doi.org/10.5194/essd-2020-308, 2021
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The project "Climate-Biogeochemistry Interactions in the Tropical Ocean" (SFB 754) was a multidisciplinary research project active from 2008 to 2019 aimed at a better understanding of the coupling between the tropical climate and ocean circulation and the ocean's oxygen and nutrient balance. On 34 research cruises, mainly in the Southeast Tropical Pacific and the Northeast Tropical Atlantic, 1071 physical, chemical and biological data sets were collected.
Stéphanie H. M. Jacquet, Dominique Lefèvre, Christian Tamburini, Marc Garel, Frédéric A. C. Le Moigne, Nagib Bhairy, and Sophie Guasco
Biogeosciences, 18, 2205–2212, https://doi.org/10.5194/bg-18-2205-2021, https://doi.org/10.5194/bg-18-2205-2021, 2021
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We present new data concerning the relation between biogenic barium (Baxs, a tracer of carbon remineralization at mesopelagic depths), O2 consumption and prokaryotic heterotrophic production (PHP) in the Mediterranean Sea. The purpose of this paper is to improve our understanding of the relation between Baxs, PHP and O2 and to test the validity of the Dehairs transfer function in the Mediterranean Sea. This relation has never been tested in the Mediterranean Sea.
Jonathan V. Trueblood, Alessia Nicosia, Anja Engel, Birthe Zäncker, Matteo Rinaldi, Evelyn Freney, Melilotus Thyssen, Ingrid Obernosterer, Julie Dinasquet, Franco Belosi, Antonio Tovar-Sánchez, Araceli Rodriguez-Romero, Gianni Santachiara, Cécile Guieu, and Karine Sellegri
Atmos. Chem. Phys., 21, 4659–4676, https://doi.org/10.5194/acp-21-4659-2021, https://doi.org/10.5194/acp-21-4659-2021, 2021
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Sea spray aerosols (SSAs) can be an important source of ice-nucleating particles (INPs) that impact cloud properties over the oceans. In the Mediterranean Sea, we found that the INPs in the seawater surface microlayer increased by an order of magnitude after a rain dust event that impacted iron and bacterial abundances. The INP properties of SSA (INPSSA) increased after a 3 d delay. Outside this event, INPSSA could be parameterized as a function of the seawater biogeochemistry.
Birthe Zäncker, Michael Cunliffe, and Anja Engel
Biogeosciences, 18, 2107–2118, https://doi.org/10.5194/bg-18-2107-2021, https://doi.org/10.5194/bg-18-2107-2021, 2021
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Fungi are found in numerous marine environments. Our study found an increased importance of fungi in the Ionian Sea, where bacterial and phytoplankton counts were reduced, but organic matter was still available, suggesting fungi might benefit from the reduced competition from bacteria in low-nutrient, low-chlorophyll (LNLC) regions.
Emilio Marañón, France Van Wambeke, Julia Uitz, Emmanuel S. Boss, Céline Dimier, Julie Dinasquet, Anja Engel, Nils Haëntjens, María Pérez-Lorenzo, Vincent Taillandier, and Birthe Zäncker
Biogeosciences, 18, 1749–1767, https://doi.org/10.5194/bg-18-1749-2021, https://doi.org/10.5194/bg-18-1749-2021, 2021
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The concentration of chlorophyll is commonly used as an indicator of the abundance of photosynthetic plankton (phytoplankton) in lakes and oceans. Our study investigates why a deep chlorophyll maximum, located near the bottom of the upper, illuminated layer develops in the Mediterranean Sea. We find that the acclimation of cells to low light is the main mechanism involved and that this deep maximum represents also a maximum in the biomass and carbon fixation activity of phytoplankton.
Nadja Triesch, Manuela van Pinxteren, Anja Engel, and Hartmut Herrmann
Atmos. Chem. Phys., 21, 163–181, https://doi.org/10.5194/acp-21-163-2021, https://doi.org/10.5194/acp-21-163-2021, 2021
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To investigate the sources of free amino acids (FAAs) in the marine atmosphere, concerted measurements (the simultaneous investigation of seawater, size-segregated aerosol particles and cloud water) were performed at the Cabo Verde islands. This study describes the transfer of FAAs as part of organic matter from the ocean into the atmosphere on a molecular level. In the investigated marine environment, a high enrichment of FAAs in submicron aerosol particles and in cloud droplets was observed.
Kahina Djaoudi, France Van Wambeke, Aude Barani, Nagib Bhairy, Servanne Chevaillier, Karine Desboeufs, Sandra Nunige, Mohamed Labiadh, Thierry Henry des Tureaux, Dominique Lefèvre, Amel Nouara, Christos Panagiotopoulos, Marc Tedetti, and Elvira Pulido-Villena
Biogeosciences, 17, 6271–6285, https://doi.org/10.5194/bg-17-6271-2020, https://doi.org/10.5194/bg-17-6271-2020, 2020
Cécile Guieu, Fabrizio D'Ortenzio, François Dulac, Vincent Taillandier, Andrea Doglioli, Anne Petrenko, Stéphanie Barrillon, Marc Mallet, Pierre Nabat, and Karine Desboeufs
Biogeosciences, 17, 5563–5585, https://doi.org/10.5194/bg-17-5563-2020, https://doi.org/10.5194/bg-17-5563-2020, 2020
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We describe here the objectives and strategy of the PEACETIME project and cruise, dedicated to dust deposition and its impacts in the Mediterranean Sea. Our strategy to go a step further forward than in previous approaches in understanding these impacts by catching a real deposition event at sea is detailed. We summarize the work performed at sea, the type of data acquired and their valorization in the papers published in the special issue.
Alexandra N. Loginova, Andrew W. Dale, Frédéric A. C. Le Moigne, Sören Thomsen, Stefan Sommer, David Clemens, Klaus Wallmann, and Anja Engel
Biogeosciences, 17, 4663–4679, https://doi.org/10.5194/bg-17-4663-2020, https://doi.org/10.5194/bg-17-4663-2020, 2020
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We measured dissolved organic carbon (DOC), nitrogen (DON) and matter (DOM) optical properties in pore waters and near-bottom waters of the eastern tropical South Pacific off Peru. The difference between diffusion-driven and net fluxes of DOC and DON and qualitative changes in DOM optical properties suggested active microbial utilisation of the released DOM at the sediment–water interface. Our results suggest that the sediment release of DOM contributes to microbial processes in the area.
Lisa Tanet, Séverine Martini, Laurie Casalot, and Christian Tamburini
Biogeosciences, 17, 3757–3778, https://doi.org/10.5194/bg-17-3757-2020, https://doi.org/10.5194/bg-17-3757-2020, 2020
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Bioluminescent bacteria, the most abundant light-emitting organisms in the ocean, can be free-living, be symbiotic or colonize organic particles. This review suggests that they act as a visual target and may indirectly influence the sequestration of biogenic carbon in oceans by increasing the attraction rate for consumers. We summarize the instrumentation available to quantify this impact in future studies and propose synthetic figures integrating these ecological and biogeochemical concepts.
Sebastian Zeppenfeld, Manuela van Pinxteren, Anja Engel, and Hartmut Herrmann
Ocean Sci., 16, 817–830, https://doi.org/10.5194/os-16-817-2020, https://doi.org/10.5194/os-16-817-2020, 2020
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An analytical method combining electro-dialysis with high-performance anionic exchange chromatography coupled to pulsed amperometric detection was developed and optimized for analyzing free and combined carbohydrates in seawater and other saline environmental samples.
Yuri Galletti, Silvia Becagli, Alcide di Sarra, Margherita Gonnelli, Elvira Pulido-Villena, Damiano M. Sferlazzo, Rita Traversi, Stefano Vestri, and Chiara Santinelli
Biogeosciences, 17, 3669–3684, https://doi.org/10.5194/bg-17-3669-2020, https://doi.org/10.5194/bg-17-3669-2020, 2020
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This paper reports the first data about atmospheric deposition of dissolved organic matter (DOM) on the island of Lampedusa. It also shows the implications for the surface marine layer by studying the impact of atmospheric organic carbon deposition in the marine ecosystem. It is a preliminary study, but it is pioneering and important for having new data that can be crucial in order to understand the impact of atmospheric deposition on the marine carbon cycle in a global climate change scenario.
Vincent Taillandier, Louis Prieur, Fabrizio D'Ortenzio, Maurizio Ribera d'Alcalà, and Elvira Pulido-Villena
Biogeosciences, 17, 3343–3366, https://doi.org/10.5194/bg-17-3343-2020, https://doi.org/10.5194/bg-17-3343-2020, 2020
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This study addresses the role played by vertical diffusion in the nutrient enrichment of the Levantine intermediate waters, a process particularly relevant inside thermohaline staircases. Thanks to a high profiling frequency over a 4-year period, BGC-Argo float observations reveal the temporal continuity of the layering patterns encountered during the cruise PEACETIME and their impact on vertical and lateral transfers of nitrate between the deep reservoir and the surface productive zone.
Antonio Tovar-Sánchez, Araceli Rodríguez-Romero, Anja Engel, Birthe Zäncker, Franck Fu, Emilio Marañón, María Pérez-Lorenzo, Matthieu Bressac, Thibaut Wagener, Sylvain Triquet, Guillaume Siour, Karine Desboeufs, and Cécile Guieu
Biogeosciences, 17, 2349–2364, https://doi.org/10.5194/bg-17-2349-2020, https://doi.org/10.5194/bg-17-2349-2020, 2020
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Residence times of particulate metals derived from aerosol deposition in the Sea Surface Microlayer of the Mediterranean Sea ranged from a couple of minutes (e.g., for Fe) to a few hours (e.g., for Cu). Microbial activity seems to play an important role in in this process and in the concentration and distribution of metals between diferent water layers.
Marie Maßmig, Jan Lüdke, Gerd Krahmann, and Anja Engel
Biogeosciences, 17, 215–230, https://doi.org/10.5194/bg-17-215-2020, https://doi.org/10.5194/bg-17-215-2020, 2020
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Little is known about the rates of bacterial element cycling in oxygen minimum zones (OMZs). We measured bacterial production and rates of extracellular hydrolytic enzymes at various in situ oxygen concentrations in the OMZ off Peru. Our field data show unhampered bacterial activity at low oxygen concentrations. Meanwhile bacterial degradation of organic matter substantially contributed to the formation of the OMZ.
Alexandra N. Loginova, Sören Thomsen, Marcus Dengler, Jan Lüdke, and Anja Engel
Biogeosciences, 16, 2033–2047, https://doi.org/10.5194/bg-16-2033-2019, https://doi.org/10.5194/bg-16-2033-2019, 2019
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High primary production in the Peruvian upwelling system is followed by rapid heterotrophic utilization of organic matter and supports the formation of one of the most intense oxygen minimum zones (OMZs) in the world. Here, we estimated vertical fluxes of oxygen and dissolved organic matter (DOM) from the surface to the OMZ. Our results suggest that DOM remineralization substantially reduces oxygen concentration in the upper water column and controls the shape of the upper oxycline.
Marie Barbieux, Julia Uitz, Bernard Gentili, Orens Pasqueron de Fommervault, Alexandre Mignot, Antoine Poteau, Catherine Schmechtig, Vincent Taillandier, Edouard Leymarie, Christophe Penkerc'h, Fabrizio D'Ortenzio, Hervé Claustre, and Annick Bricaud
Biogeosciences, 16, 1321–1342, https://doi.org/10.5194/bg-16-1321-2019, https://doi.org/10.5194/bg-16-1321-2019, 2019
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As commonly observed in oligotrophic stratified waters, a subsurface (or deep) chlorophyll maximum (SCM) frequently characterizes the vertical distribution of phytoplankton chlorophyll in the Mediterranean Sea. SCMs often result from photoacclimation of the phytoplankton organisms. However they can also result from an actual increase in phytoplankton carbon biomass. Our results also suggest that a variety of intermediate types of SCMs are encountered between these two endmember situations.
Debany Fonseca-Batista, Xuefeng Li, Virginie Riou, Valérie Michotey, Florian Deman, François Fripiat, Sophie Guasco, Natacha Brion, Nolwenn Lemaitre, Manon Tonnard, Morgane Gallinari, Hélène Planquette, Frédéric Planchon, Géraldine Sarthou, Marc Elskens, Julie LaRoche, Lei Chou, and Frank Dehairs
Biogeosciences, 16, 999–1017, https://doi.org/10.5194/bg-16-999-2019, https://doi.org/10.5194/bg-16-999-2019, 2019
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Dinitrogen fixation and primary production were investigated using stable isotope incubation experiments along two transects off the Western Iberian Margin in May 2014 close to the end of the phytoplankton spring bloom. We observed substantial N2 fixation activities (up to 1533 µmol N m-2 d-1) associated with a predominance of unicellular cyanobacteria and non-cyanobacterial diazotrophs, which seemed to be promoted by the presence of bloom-derived organic matter and excess phosphorus.
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.
Carolina Cisternas-Novoa, Frédéric A. C. Le Moigne, and Anja Engel
Biogeosciences, 16, 927–947, https://doi.org/10.5194/bg-16-927-2019, https://doi.org/10.5194/bg-16-927-2019, 2019
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We investigate the composition and vertical fluxes of POM in two deep basins of the Baltic Sea (GB: Gotland Basin and LD: Landsort Deep). The two basins showed different O2 regimes resulting from the intrusion of oxygen-rich water from the North Sea that ventilated the deep waters in GB, but not in LD.
In GB, O2 intrusions lead to a high abundance of manganese oxides that aggregate with POM, altering its composition and vertical flux and contributing to a higher POC transfer efficiency in GB.
Christos Panagiotopoulos, Mireille Pujo-Pay, Mar Benavides, France Van Wambeke, and Richard Sempéré
Biogeosciences, 16, 105–116, https://doi.org/10.5194/bg-16-105-2019, https://doi.org/10.5194/bg-16-105-2019, 2019
Nicholas Bock, France Van Wambeke, Moïra Dion, and Solange Duhamel
Biogeosciences, 15, 3909–3925, https://doi.org/10.5194/bg-15-3909-2018, https://doi.org/10.5194/bg-15-3909-2018, 2018
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We report the distribution of major nano- and pico-plankton groups in the western tropical South Pacific. We found microbial community structure to be typical of highly stratified regions of the open ocean, with significant contributions to total biomass by picophytoeukaryotes, and N2 fixation playing a central role in regulating ecosystem processes. Our results also suggest a reduction in the importance of predation in regulating bacteria populations under nutrient-limited conditions.
Cui-Ci Sun, Martin Sperling, and Anja Engel
Biogeosciences, 15, 3577–3589, https://doi.org/10.5194/bg-15-3577-2018, https://doi.org/10.5194/bg-15-3577-2018, 2018
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Biogenic gel particles such as transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP) are important components in the sea-surface microlayer (SML). Their potential role in air–sea gas exchange and in primary organic aerosol emission has generated considerable research interest. Our wind wave channel experiment revealed how wind speed controls the accumulation and size distribution of biogenic gel particles in the SML.
France Van Wambeke, Audrey Gimenez, Solange Duhamel, Cécile Dupouy, Dominique Lefevre, Mireille Pujo-Pay, and Thierry Moutin
Biogeosciences, 15, 2669–2689, https://doi.org/10.5194/bg-15-2669-2018, https://doi.org/10.5194/bg-15-2669-2018, 2018
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The western tropical South Pacific Ocean has recently been shown to be a hotspot for biological nitrogen fixation. In this study, we examined the horizontal and vertical distribution of heterotrophic prokaryotic production alongside photosynthetic rates, nitrogen fixation rates and phosphate turnover times across the western tropical South Pacific Ocean, in order to relate these fluxes to bottom–up controls (related to nitrogen, phosphate and labile C availability).
Vincent Taillandier, Thibaut Wagener, Fabrizio D'Ortenzio, Nicolas Mayot, Hervé Legoff, Joséphine Ras, Laurent Coppola, Orens Pasqueron de Fommervault, Catherine Schmechtig, Emilie Diamond, Henry Bittig, Dominique Lefevre, Edouard Leymarie, Antoine Poteau, and Louis Prieur
Earth Syst. Sci. Data, 10, 627–641, https://doi.org/10.5194/essd-10-627-2018, https://doi.org/10.5194/essd-10-627-2018, 2018
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We report on data from an oceanographic cruise, covering western, central and eastern parts of the Mediterranean Sea. This cruise was fully dedicated to the maintenance and the metrological verification of a biogeochemical observing system based on a fleet of BGC-Argo floats.
Anja Engel, Hannes Wagner, Frédéric A. C. Le Moigne, and Samuel T. Wilson
Biogeosciences, 14, 1825–1838, https://doi.org/10.5194/bg-14-1825-2017, https://doi.org/10.5194/bg-14-1825-2017, 2017
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To better understand the role of oxygen for the biological carbon pump, we studied particle fluxes through hypoxic waters in the eastern tropical North Atlantic. Attenuation of organic carbon fluxes over depth was lower than expected from seawater temperatures, indicating co-effects of oxygen concentration. Differences were observed for individual organic components, suggesting that future carbon export fluxes may depend on changes in surface ocean organic matter quality under global change.
Helmke Hepach, Birgit Quack, Susann Tegtmeier, Anja Engel, Astrid Bracher, Steffen Fuhlbrügge, Luisa Galgani, Elliot L. Atlas, Johannes Lampel, Udo Frieß, and Kirstin Krüger
Atmos. Chem. Phys., 16, 12219–12237, https://doi.org/10.5194/acp-16-12219-2016, https://doi.org/10.5194/acp-16-12219-2016, 2016
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We present surface seawater measurements of bromo- and iodocarbons, which are involved in numerous atmospheric processes such as tropospheric and stratospheric ozone chemistry, from the highly productive Peruvian upwelling. By combining trace gas measurements, characterization of organic matter and phytoplankton species, and tropospheric modelling, we show that large amounts of iodocarbons produced from the pool of organic matter may contribute strongly to local tropospheric iodine loading.
Ilana Berman-Frank, Dina Spungin, Eyal Rahav, France Van Wambeke, Kendra Turk-Kubo, and Thierry Moutin
Biogeosciences, 13, 3793–3805, https://doi.org/10.5194/bg-13-3793-2016, https://doi.org/10.5194/bg-13-3793-2016, 2016
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In the marine environment, sticky sugar-containing gels, termed transparent exopolymeric particles (TEP), are produced from biological sources and physical and chemical processes. These compounds are essential vectors enhancing downward flow of organic matter and its storage at depth. Spatial and temporal dynamics of TEPs were followed for 23 days during the VAHINE mesocosm experiment that investigated the fate of nitrogen and carbon derived from organisms fixing atmospheric N2 (diazotrophs).
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.
Marc Tedetti, Lauriane Marie, Rüdiger Röttgers, Martine Rodier, France Van Wambeke, Sandra Helias, Mathieu Caffin, Véronique Cornet-Barthaux, and Cécile Dupouy
Biogeosciences, 13, 3283–3303, https://doi.org/10.5194/bg-13-3283-2016, https://doi.org/10.5194/bg-13-3283-2016, 2016
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In the framework of the VAHINE project, we investigated the spectral characteristics and the variability of dissolved and particulate chromophoric materials throughout a 23-day mesocosm experiment conducted in the south-west Pacific at the mouth of the New Caledonian coral lagoon. We found that the dynamics of CDOM and particulate matter absorption were strongly coupled with those of cyanobacteria Synechococcus spp. and bacterial production.
France Van Wambeke, Ulrike Pfreundt, Aude Barani, Hugo Berthelot, Thierry Moutin, Martine Rodier, Wolfgang R. Hess, and Sophie Bonnet
Biogeosciences, 13, 3187–3202, https://doi.org/10.5194/bg-13-3187-2016, https://doi.org/10.5194/bg-13-3187-2016, 2016
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The phytoplankton is at the base of the plankton food web in large parts of oceanic "deserts" such as the South Pacific Ocean, where nitrogen sources limit activity. Mesocosms were fertilized with phosphorus to stimulate diazotrophy (atmospheric N2 fixation). Mostly diazotroph-derived nitrogen fuelled the heterotrophic bacterial community through indirect processes generating dissolved organic matter and detritus, such as mortality, lysis and grazing of both diazotrophs and non-diazotrophs.
Luisa Galgani and Anja Engel
Biogeosciences, 13, 2453–2473, https://doi.org/10.5194/bg-13-2453-2016, https://doi.org/10.5194/bg-13-2453-2016, 2016
Ulrike Pfreundt, France Van Wambeke, Mathieu Caffin, Sophie Bonnet, and Wolfgang R. Hess
Biogeosciences, 13, 2319–2337, https://doi.org/10.5194/bg-13-2319-2016, https://doi.org/10.5194/bg-13-2319-2016, 2016
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The Southwest Pacific has one of the highest N2 fixation rates in the global ocean, yet information is scarce on the bacterioplankton interrelationships. We detected high microbial diversity in the New Caledonia lagoon and inside a 50 000 L experimental enclosure of the same water mass over 3 weeks and give evidence for previously unknown niche partitioning. Phosphate fertilization promoted the growth of efficient N2 fixing cyanobacteria triggering the growth of most heterotrophic bacteria.
Anja Engel and Luisa Galgani
Biogeosciences, 13, 989–1007, https://doi.org/10.5194/bg-13-989-2016, https://doi.org/10.5194/bg-13-989-2016, 2016
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The sea-surface microlayer (SML) is a very thin layer at the interface between the ocean and the atmosphere. Organic compounds in the SML may influence the exchange of gases between seawater and air, as well as primary aerosol emission. Here, we report results from the SOPRAN M91 cruise, a field study to the coastal upwelling regime off Peru's coast in 2012. Our study provides novel insight to the relationship between plankton productivity, wind speed and organic matter accumulation in the SML.
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
H. Berthelot, T. Moutin, S. L'Helguen, K. Leblanc, S. Hélias, O. Grosso, N. Leblond, B. Charrière, and S. Bonnet
Biogeosciences, 12, 4099–4112, https://doi.org/10.5194/bg-12-4099-2015, https://doi.org/10.5194/bg-12-4099-2015, 2015
C. Borchard and A. Engel
Biogeosciences, 12, 1271–1284, https://doi.org/10.5194/bg-12-1271-2015, https://doi.org/10.5194/bg-12-1271-2015, 2015
U. Christaki, D. Lefèvre, C. Georges, J. Colombet, P. Catala, C. Courties, T. Sime-Ngando, S. Blain, and I. Obernosterer
Biogeosciences, 11, 6739–6753, https://doi.org/10.5194/bg-11-6739-2014, https://doi.org/10.5194/bg-11-6739-2014, 2014
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The concurrent investigation of several parameters has provided insight into two key roles of heterotrophic bacteria, and the microbial food web functioning, at the onset and late phase of the spring phytoplankton bloom induced by natural iron fertilization in the Southern Ocean.
E. Pulido-Villena, A.-C. Baudoux, I. Obernosterer, M. Landa, J. Caparros, P. Catala, C. Georges, J. Harmand, and C. Guieu
Biogeosciences, 11, 5607–5619, https://doi.org/10.5194/bg-11-5607-2014, https://doi.org/10.5194/bg-11-5607-2014, 2014
C. Guieu, C. Ridame, E. Pulido-Villena, M. Bressac, K. Desboeufs, and F. Dulac
Biogeosciences, 11, 5621–5635, https://doi.org/10.5194/bg-11-5621-2014, https://doi.org/10.5194/bg-11-5621-2014, 2014
A. Silyakova, R. G. J. Bellerby, K. G. Schulz, J. Czerny, T. Tanaka, G. Nondal, U. Riebesell, A. Engel, T. De Lange, and A. Ludvig
Biogeosciences, 10, 4847–4859, https://doi.org/10.5194/bg-10-4847-2013, https://doi.org/10.5194/bg-10-4847-2013, 2013
J. Czerny, K. G. Schulz, T. Boxhammer, R. G. J. Bellerby, J. Büdenbender, A. Engel, S. A. Krug, A. Ludwig, K. Nachtigall, G. Nondal, B. Niehoff, A. Silyakova, and U. Riebesell
Biogeosciences, 10, 3109–3125, https://doi.org/10.5194/bg-10-3109-2013, https://doi.org/10.5194/bg-10-3109-2013, 2013
S. D. Archer, S. A. Kimmance, J. A. Stephens, F. E. Hopkins, R. G. J. Bellerby, K. G. Schulz, J. Piontek, and A. Engel
Biogeosciences, 10, 1893–1908, https://doi.org/10.5194/bg-10-1893-2013, https://doi.org/10.5194/bg-10-1893-2013, 2013
J. Unger, S. Endres, N. Wannicke, A. Engel, M. Voss, G. Nausch, and M. Nausch
Biogeosciences, 10, 1483–1499, https://doi.org/10.5194/bg-10-1483-2013, https://doi.org/10.5194/bg-10-1483-2013, 2013
A. Engel, C. Borchard, J. Piontek, K. G. Schulz, U. Riebesell, and R. Bellerby
Biogeosciences, 10, 1291–1308, https://doi.org/10.5194/bg-10-1291-2013, https://doi.org/10.5194/bg-10-1291-2013, 2013
J. Piontek, C. Borchard, M. Sperling, K. G. Schulz, U. Riebesell, and A. Engel
Biogeosciences, 10, 297–314, https://doi.org/10.5194/bg-10-297-2013, https://doi.org/10.5194/bg-10-297-2013, 2013
M. Sperling, J. Piontek, G. Gerdts, A. Wichels, H. Schunck, A.-S. Roy, J. La Roche, J. Gilbert, J. I. Nissimov, L. Bittner, S. Romac, U. Riebesell, and A. Engel
Biogeosciences, 10, 181–191, https://doi.org/10.5194/bg-10-181-2013, https://doi.org/10.5194/bg-10-181-2013, 2013
K. G. Schulz, R. G. J. Bellerby, C. P. D. Brussaard, J. Büdenbender, J. Czerny, A. Engel, M. Fischer, S. Koch-Klavsen, S. A. Krug, S. Lischka, A. Ludwig, M. Meyerhöfer, G. Nondal, A. Silyakova, A. Stuhr, and U. Riebesell
Biogeosciences, 10, 161–180, https://doi.org/10.5194/bg-10-161-2013, https://doi.org/10.5194/bg-10-161-2013, 2013
Related subject area
Biodiversity and Ecosystem Function: Marine
Building your own mountain: the effects, limits, and drawbacks of cold-water coral ecosystem engineering
Phytoplankton response to increased nickel in the context of ocean alkalinity enhancement
Diversity and density relationships between lebensspuren and tracemaking organisms: a study case from abyssal northwest Pacific
Technical note: An autonomous flow-through salinity and temperature perturbation mesocosm system for multi-stressor experiments
Reviews and syntheses: The clam before the storm – a meta-analysis showing the effect of combined climate change stressors on bivalves
A step towards measuring connectivity in the deep sea: elemental fingerprints of mollusk larval shells discriminate hydrothermal vent sites
Simulated terrestrial runoff shifts the metabolic balance of a coastal Mediterranean plankton community toward heterotrophy
Structural complexity and benthic metabolism: resolving the links between carbon cycling and biodiversity in restored seagrass meadows
Contrasting carbon cycling in the benthic food webs between river-fed, high-energy canyon and upper continental slope
Spawner weight and ocean temperature drive Allee effect dynamics in Atlantic cod, Gadus morhua: inherent and emergent density regulation
Bacterioplankton dark CO2 fixation in oligotrophic waters
The bottom mixed layer depth as an indicator of subsurface Chlorophyll a distribution
Ideas and perspectives: The fluctuating nature of oxygen shapes the ecology of aquatic habitats and their biogeochemical cycles – the aquatic oxyscape
Impact of deoxygenation and warming on global marine species in the 21st century
A critical trade-off between nitrogen quota and growth allows Coccolithus braarudii life cycle phases’ to exploit varying environment
Ecological divergence of a mesocosm in an eastern boundary upwelling system assessed with multi-marker environmental DNA metabarcoding
Unique benthic foraminiferal communities (stained) in diverse environments of sub-Antarctic fjords, South Georgia
Upwelled plankton community modulates surface bloom succession and nutrient availability in a natural plankton assemblage
First phytoplankton community assessment of the Kong Håkon VII Hav, Southern Ocean, during austral autumn
Early life stages of a Mediterranean coral are vulnerable to ocean warming and acidification
Mediterranean seagrasses as carbon sinks: methodological and regional differences
Contrasting vertical distributions of recent planktic foraminifera off Indonesia during the southeast monsoon: implications for paleoceanographic reconstructions
The onset of the spring phytoplankton bloom in the coastal North Sea supports the Disturbance Recovery Hypothesis
Species richness and functional attributes of fish assemblages across a large-scale salinity gradient in shallow coastal areas
Modeling the growth and sporulation dynamics of the macroalga Ulva in mixed-age populations in cultivation and the formation of green tides
Spatial changes in community composition and food web structure of mesozooplankton across the Adriatic basin (Mediterranean Sea)
Predicting mangrove forest dynamics across a soil salinity gradient using an individual-based vegetation model linked with plant hydraulics
Will daytime community calcification reflect reef accretion on future, degraded coral reefs?
Modeling polar marine ecosystem functions guided by bacterial physiological and taxonomic traits
Quantifying functional consequences of habitat degradation on a Caribbean coral reef
Enhanced chlorophyll-a concentration in the wake of Sable Island, eastern Canada, revealed by two decades of satellite observations: a response to grey seal population dynamics?
Population dynamics and reproduction strategies of planktonic foraminifera in the open ocean
The Bouraké semi-enclosed lagoon (New Caledonia) – a natural laboratory to study the lifelong adaptation of a coral reef ecosystem to extreme environmental conditions
Atypical, high-diversity assemblages of foraminifera in a mangrove estuary in northern Brazil
Permanent ectoplasmic structures in deep-sea Cibicides and Cibicidoides taxa – long-term observations at in situ pressure
Ideas and perspectives: Ushering the Indian Ocean into the UN Decade of Ocean Science for Sustainable Development (UNDOSSD) through marine ecosystem research and operational services – an early career's take
Persistent effects of sand extraction on habitats and associated benthic communities in the German Bight
A 2-decade (1988–2009) record of diatom fluxes in the Mauritanian coastal upwelling: impact of low-frequency forcing and a two-step shift in the species composition
Review and syntheses: Impacts of turbidity flows on deep-sea benthic communities
Ideas and perspectives: When ocean acidification experiments are not the same, repeatability is not tested
The effect of the salinity, light regime and food source on carbon and nitrogen uptake in a benthic foraminifer
Changes in population depth distribution and oxygen stratification are involved in the current low condition of the eastern Baltic Sea cod (Gadus morhua)
Effects of spatial variability on the exposure of fish to hypoxia: a modeling analysis for the Gulf of Mexico
Plant genotype determines biomass response to flooding frequency in tidal wetlands
Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean and implications for carbon export fluxes
Characterization of particle-associated and free-living bacterial and archaeal communities along the water columns of the South China Sea
Adult life strategy affects distribution patterns in abyssal isopods – implications for conservation in Pacific nodule areas
Diversity and distribution of nitrogen fixation genes in the oxygen minimum zones of the world oceans
Structure and function of epipelagic mesozooplankton and their response to dust deposition events during the spring PEACETIME cruise in the Mediterranean Sea
Distribution of planktonic foraminifera in the subtropical South Atlantic: depth hierarchy of controlling factors
Anna-Selma van der Kaaden, Sandra R. Maier, Siluo Chen, Laurence H. De Clippele, Evert de Froe, Theo Gerkema, Johan van de Koppel, Furu Mienis, Christian Mohn, Max Rietkerk, Karline Soetaert, and Dick van Oevelen
Biogeosciences, 21, 973–992, https://doi.org/10.5194/bg-21-973-2024, https://doi.org/10.5194/bg-21-973-2024, 2024
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Combining hydrodynamic simulations and annotated videos, we separated which hydrodynamic variables that determine reef cover are engineered by cold-water corals and which are not. Around coral mounds, hydrodynamic zones seem to create a typical reef zonation, restricting corals from moving deeper (the expected response to climate warming). But non-engineered downward velocities in winter (e.g. deep winter mixing) seem more important for coral reef growth than coral engineering.
Xiaoke Xin, Giulia Faucher, and Ulf Riebesell
Biogeosciences, 21, 761–772, https://doi.org/10.5194/bg-21-761-2024, https://doi.org/10.5194/bg-21-761-2024, 2024
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Ocean alkalinity enhancement (OAE) is a promising approach to remove CO2 by accelerating natural rock weathering. However, some of the alkaline substances contain trace metals which could be toxic to marine life. By exposing three representative phytoplankton species to Ni released from alkaline materials, we observed varying responses of phytoplankton to nickel concentrations, suggesting caution should be taken and toxic thresholds should be avoided in OAE with Ni-rich materials.
Olmo Miguez-Salas, Angelika Brandt, Henry Knauber, and Torben Riehl
Biogeosciences, 21, 641–655, https://doi.org/10.5194/bg-21-641-2024, https://doi.org/10.5194/bg-21-641-2024, 2024
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In the deep sea, the interaction between benthic fauna (tracemakers) and substrate can be preserved as traces (i.e. lebensspuren), which are common features of seafloor landscapes, rendering them promising proxies for inferring biodiversity from marine images. No general correlation was observed between traces and benthic fauna. However, a local correlation was observed between specific stations depending on unknown tracemakers, tracemaker behaviour, and lebensspuren morphotypes.
Cale A. Miller, Pierre Urrutti, Jean-Pierre Gattuso, Steeve Comeau, Anaïs Lebrun, Samir Alliouane, Robert W. Schlegel, and Frédéric Gazeau
Biogeosciences, 21, 315–333, https://doi.org/10.5194/bg-21-315-2024, https://doi.org/10.5194/bg-21-315-2024, 2024
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This work describes an experimental system that can replicate and manipulate environmental conditions in marine or aquatic systems. Here, we show how the temperature and salinity of seawater delivered from a fjord is manipulated to experimental tanks on land. By constantly monitoring temperature and salinity in each tank via a computer program, the system continuously adjusts automated flow valves to ensure the seawater in each tank matches the targeted experimental conditions.
Rachel A. Kruft Welton, George Hoppit, Daniela N. Schmidt, James D. Witts, and Benjamin C. Moon
Biogeosciences, 21, 223–239, https://doi.org/10.5194/bg-21-223-2024, https://doi.org/10.5194/bg-21-223-2024, 2024
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We conducted a meta-analysis of known experimental literature examining how marine bivalve growth rates respond to climate change. Growth is usually negatively impacted by climate change. Bivalve eggs/larva are generally more vulnerable than either juveniles or adults. Available data on the bivalve response to climate stressors are biased towards early growth stages (commercially important in the Global North), and many families have only single experiments examining climate change impacts.
Vincent Mouchi, Christophe Pecheyran, Fanny Claverie, Cécile Cathalot, Marjolaine Matabos, Yoan Germain, Olivier Rouxel, Didier Jollivet, Thomas Broquet, and Thierry Comtet
Biogeosciences, 21, 145–160, https://doi.org/10.5194/bg-21-145-2024, https://doi.org/10.5194/bg-21-145-2024, 2024
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The impact of deep-sea mining will depend critically on the ability of larval dispersal of hydrothermal mollusks to connect and replenish natural populations. However, assessing connectivity is extremely challenging, especially in the deep sea. Here, we investigate the potential of using the chemical composition of larval shells to discriminate larval origins between multiple hydrothermal sites in the southwest Pacific. Our results confirm that this method can be applied with high accuracy.
Tanguy Soulié, Francesca Vidussi, Justine Courboulès, Marie Heydon, Sébastien Mas, Florian Voron, Carolina Cantoni, Fabien Joux, and Behzad Mostajir
EGUsphere, https://doi.org/10.5194/egusphere-2023-2782, https://doi.org/10.5194/egusphere-2023-2782, 2023
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Due to climate change, it is projected that extreme rainfall events, bringing terrestrial matter into coastal seas, will occur more frequently in the Mediterranean region. To test the effects of runoffs of terrestrial matter on plankton communities from Mediterranean coastal waters, an in situ mesocosm experiment was conducted. The simulated runoff affected key processes mediated by plankton, such as primary production and respiration, suggesting major consequences of such events.
Theodor Kindeberg, Karl M. Attard, Jana Hüller, Julia Müller, Cintia O. Quintana, and Eduardo Infantes
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-173, https://doi.org/10.5194/bg-2023-173, 2023
Revised manuscript accepted for BG
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Seagrass meadows are hotspots for biodiversity and productivity and planting seagrass is proposed as a tool for mitigating biodiversity loss and climate change. We assessed seagrass planted in different years and found that benthic oxygen and carbon fluxes increased as the seabed developed from bare sediments to a mature seagrass meadow. This increase was partly linked to the diversity of colonizing algae which increased the light-use efficiency of the seagrass meadow community.
Chueh-Chen Tung, Yu-Shih Lin, Jian-Xiang Liao, Tzu-Hsuan Tu, James T. Liu, Li-Hung Lin, Pei-Ling Wang, and Chih-Lin Wei
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-161, https://doi.org/10.5194/bg-2023-161, 2023
Revised manuscript accepted for BG
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This study contrasts seabed food webs between a river-fed, high-energy canyon and the nearby slope. We show higher organic carbon (OC) flows through the canyon than the slope. Bacteria dominated the canyon, while seabed fauna contributed more to the slope food web. Due to frequent perturbation, the canyon had a lower faunal stock and OC recycling. Only 1 % of the seabed OC flux enters the canyon food web, suggesting a significant role of the river-fed canyon in transporting OC to the deep sea.
Anna-Marie Winter, Nadezda Vasilyeva, and Artem Vladimirov
Biogeosciences, 20, 3683–3716, https://doi.org/10.5194/bg-20-3683-2023, https://doi.org/10.5194/bg-20-3683-2023, 2023
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There is an increasing number of fish in poor state, and many do not recover, even when fishing pressure is ceased. An Allee effect can hinder population recovery because it suppresses the fish's productivity at low abundance. With a model fitted to 17 Atlantic cod stocks, we find that ocean warming and fishing can cause an Allee effect. If present, the Allee effect hinders fish recovery. This shows that Allee effects are dynamic, not uncommon, and calls for precautionary management measures.
Afrah Alothman, Daffne López-Sandoval, Carlos M. Duarte, and Susana Agustí
Biogeosciences, 20, 3613–3624, https://doi.org/10.5194/bg-20-3613-2023, https://doi.org/10.5194/bg-20-3613-2023, 2023
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This study investigates bacterial dissolved inorganic carbon (DIC) fixation in the Red Sea, an oligotrophic ecosystem, using stable-isotope labeling and spectroscopy. The research reveals that bacterial DIC fixation significantly contributes to total DIC fixation, in the surface and deep water. The study demonstrates that as primary production decreases, the role of bacterial DIC fixation increases, emphasizing its importance with photosynthesis in estimating oceanic carbon dioxide production.
Arianna Zampollo, Thomas Cornulier, Rory O'Hara Murray, Jacqueline Fiona Tweddle, James Dunning, and Beth E. Scott
Biogeosciences, 20, 3593–3611, https://doi.org/10.5194/bg-20-3593-2023, https://doi.org/10.5194/bg-20-3593-2023, 2023
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This paper highlights the use of the bottom mixed layer depth (BMLD: depth between the end of the pycnocline and the mixed layer below) to investigate subsurface Chlorophyll a (a proxy of primary production) in temperate stratified shelf waters. The strict correlation between subsurface Chl a and BMLD becomes relevant in shelf-productive waters where multiple stressors (e.g. offshore infrastructure) will change the stratification--mixing balance and related carbon fluxes.
Marco Fusi, Sylvain Rigaud, Giovanna Guadagnin, Alberto Barausse, Ramona Marasco, Daniele Daffonchio, Julie Régis, Louison Huchet, Capucine Camin, Laura Pettit, Cristina Vina-Herbon, and Folco Giomi
Biogeosciences, 20, 3509–3521, https://doi.org/10.5194/bg-20-3509-2023, https://doi.org/10.5194/bg-20-3509-2023, 2023
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Oxygen availability in marine water and freshwater is very variable at daily and seasonal scales. The dynamic nature of oxygen fluctuations has important consequences for animal and microbe physiology and ecology, yet it is not fully understood. In this paper, we showed the heterogeneous nature of the aquatic oxygen landscape, which we defined here as the
oxyscape, and we addressed the importance of considering the oxyscape in the modelling and managing of aquatic ecosystems.
Anne L. Morée, Tayler M. Clarke, William W. L. Cheung, and Thomas L. Frölicher
Biogeosciences, 20, 2425–2454, https://doi.org/10.5194/bg-20-2425-2023, https://doi.org/10.5194/bg-20-2425-2023, 2023
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Ocean temperature and oxygen shape marine habitats together with species’ characteristics. We calculated the impacts of projected 21st-century warming and oxygen loss on the contemporary habitat volume of 47 marine species and described the drivers of these impacts. Most species lose less than 5 % of their habitat at 2 °C of global warming, but some species incur losses 2–3 times greater than that. We also calculate which species may be most vulnerable to climate change and why this is the case.
Joost de Vries, Fanny Monteiro, Gerald Langer, Colin Brownlee, and Glen Wheeler
EGUsphere, https://doi.org/10.5194/egusphere-2023-880, https://doi.org/10.5194/egusphere-2023-880, 2023
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Calcifying phytoplankton (coccolithophores) utilize a life cycle in which they can grow and divide in two different phases. These two phases (HET and HOL) vary in terms of their physiology and distributions, with many unknowns about what the key differences are. Using a combination of lab experiments and model simulations we find that nutrient storage is a critical difference between the two phases, and that this difference allows them to inhabit different nitrogen input regimes.
Markus A. Min, David M. Needham, Sebastian Sudek, Nathan Kobun Truelove, Kathleen J. Pitz, Gabriela M. Chavez, Camille Poirier, Bente Gardeler, Elisabeth von der Esch, Andrea Ludwig, Ulf Riebesell, Alexandra Z. Worden, and Francisco P. Chavez
Biogeosciences, 20, 1277–1298, https://doi.org/10.5194/bg-20-1277-2023, https://doi.org/10.5194/bg-20-1277-2023, 2023
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Emerging molecular methods provide new ways of understanding how marine communities respond to changes in ocean conditions. Here, environmental DNA was used to track the temporal evolution of biological communities in the Peruvian coastal upwelling system and in an adjacent enclosure where upwelling was simulated. We found that the two communities quickly diverged, with the open ocean being one found during upwelling and the enclosure evolving to one found under stratified conditions.
Wojciech Majewski, Witold Szczuciński, and Andrew J. Gooday
Biogeosciences, 20, 523–544, https://doi.org/10.5194/bg-20-523-2023, https://doi.org/10.5194/bg-20-523-2023, 2023
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We studied foraminifera living in the fjords of South Georgia, a sub-Antarctic island sensitive to climate change. As conditions in water and on the seafloor vary, different associations of these microorganisms dominate far inside, in the middle, and near fjord openings. Assemblages in inner and middle parts of fjords are specific to South Georgia, but they may become widespread with anticipated warming. These results are important for interpretating fossil records and monitoring future change.
Allanah Joy Paul, Lennart Thomas Bach, Javier Arístegui, Elisabeth von der Esch, Nauzet Hernández-Hernández, Jonna Piiparinen, Laura Ramajo, Kristian Spilling, and Ulf Riebesell
Biogeosciences, 19, 5911–5926, https://doi.org/10.5194/bg-19-5911-2022, https://doi.org/10.5194/bg-19-5911-2022, 2022
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We investigated how different deep water chemistry and biology modulate the response of surface phytoplankton communities to upwelling in the Peruvian coastal zone. Our results show that the most influential drivers were the ratio of inorganic nutrients (N : P) and the microbial community present in upwelling source water. These led to unexpected and variable development in the phytoplankton assemblage that could not be predicted by the amount of inorganic nutrients alone.
Hanna M. Kauko, Philipp Assmy, Ilka Peeken, Magdalena Różańska-Pluta, Józef M. Wiktor, Gunnar Bratbak, Asmita Singh, Thomas J. Ryan-Keogh, and Sebastien Moreau
Biogeosciences, 19, 5449–5482, https://doi.org/10.5194/bg-19-5449-2022, https://doi.org/10.5194/bg-19-5449-2022, 2022
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This article studies phytoplankton (microscopic
plantsin the ocean capable of photosynthesis) in Kong Håkon VII Hav in the Southern Ocean. Different species play different roles in the ecosystem, and it is therefore important to assess the species composition. We observed that phytoplankton blooms in this area are formed by large diatoms with strong silica armors, which can lead to high silica (and sometimes carbon) export to depth and be important prey for krill.
Chloe Carbonne, Steeve Comeau, Phoebe T. W. Chan, Keyla Plichon, Jean-Pierre Gattuso, and Núria Teixidó
Biogeosciences, 19, 4767–4777, https://doi.org/10.5194/bg-19-4767-2022, https://doi.org/10.5194/bg-19-4767-2022, 2022
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For the first time, our study highlights the synergistic effects of a 9-month warming and acidification combined stress on the early life stages of a Mediterranean azooxanthellate coral, Astroides calycularis. Our results predict a decrease in dispersion, settlement, post-settlement linear extention, budding and survival under future global change and that larvae and recruits of A. calycularis are stages of interest for this Mediterranean coral resistance, resilience and conservation.
Iris E. Hendriks, Anna Escolano-Moltó, Susana Flecha, Raquel Vaquer-Sunyer, Marlene Wesselmann, and Núria Marbà
Biogeosciences, 19, 4619–4637, https://doi.org/10.5194/bg-19-4619-2022, https://doi.org/10.5194/bg-19-4619-2022, 2022
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Seagrasses are marine plants with the capacity to act as carbon sinks due to their high primary productivity, using carbon for growth. This capacity can play a key role in climate change mitigation. We compiled and published data showing that two Mediterranean seagrass species have different metabolic rates, while the study method influences the rates of the measurements. Most communities act as carbon sinks, while the western basin might be more productive than the eastern Mediterranean.
Raúl Tapia, Sze Ling Ho, Hui-Yu Wang, Jeroen Groeneveld, and Mahyar Mohtadi
Biogeosciences, 19, 3185–3208, https://doi.org/10.5194/bg-19-3185-2022, https://doi.org/10.5194/bg-19-3185-2022, 2022
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We report census counts of planktic foraminifera in depth-stratified plankton net samples off Indonesia. Our results show that the vertical distribution of foraminifera species routinely used in paleoceanographic reconstructions varies in hydrographically distinct regions, likely in response to food availability. Consequently, the thermal gradient based on mixed layer and thermocline dwellers also differs for these regions, suggesting potential implications for paleoceanographic reconstructions.
Ricardo González-Gil, Neil S. Banas, Eileen Bresnan, and Michael R. Heath
Biogeosciences, 19, 2417–2426, https://doi.org/10.5194/bg-19-2417-2022, https://doi.org/10.5194/bg-19-2417-2022, 2022
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In oceanic waters, the accumulation of phytoplankton biomass in winter, when light still limits growth, is attributed to a decrease in grazing as the mixed layer deepens. However, in coastal areas, it is not clear whether winter biomass can accumulate without this deepening. Using 21 years of weekly data, we found that in the Scottish coastal North Sea, the seasonal increase in light availability triggers the accumulation of phytoplankton biomass in winter, when light limitation is strongest.
Birgit Koehler, Mårten Erlandsson, Martin Karlsson, and Lena Bergström
Biogeosciences, 19, 2295–2312, https://doi.org/10.5194/bg-19-2295-2022, https://doi.org/10.5194/bg-19-2295-2022, 2022
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Understanding species richness patterns remains a challenge for biodiversity management. We estimated fish species richness over a coastal salinity gradient (3–32) with a method that allowed comparing data from various sources. Species richness was 3-fold higher at high vs. low salinity, and salinity influenced species’ habitat preference, mobility and feeding type. If climate change causes upper-layer freshening of the Baltic Sea, further shifts along the identified patterns may be expected.
Uri Obolski, Thomas Wichard, Alvaro Israel, Alexander Golberg, and Alexander Liberzon
Biogeosciences, 19, 2263–2271, https://doi.org/10.5194/bg-19-2263-2022, https://doi.org/10.5194/bg-19-2263-2022, 2022
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The algal genus Ulva plays a major role in coastal ecosystems worldwide and is a promising prospect as an seagriculture crop. A substantial hindrance to cultivating Ulva arises from sudden sporulation, leading to biomass loss. This process is not yet well understood. Here, we characterize the dynamics of Ulva growth, considering the potential impact of sporulation inhibitors, using a mathematical model. Our findings are an essential step towards understanding the dynamics of Ulva growth.
Emanuela Fanelli, Samuele Menicucci, Sara Malavolti, Andrea De Felice, and Iole Leonori
Biogeosciences, 19, 1833–1851, https://doi.org/10.5194/bg-19-1833-2022, https://doi.org/10.5194/bg-19-1833-2022, 2022
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Zooplankton play a key role in marine ecosystems, forming the base of the marine food web and a link between primary producers and higher-order consumers, such as fish. This aspect is crucial in the Adriatic basin, one of the most productive and overexploited areas of the Mediterranean Sea. A better understanding of community and food web structure and their response to water mass changes is essential under a global warming scenario, as zooplankton are sensitive to climate change.
Masaya Yoshikai, Takashi Nakamura, Rempei Suwa, Sahadev Sharma, Rene Rollon, Jun Yasuoka, Ryohei Egawa, and Kazuo Nadaoka
Biogeosciences, 19, 1813–1832, https://doi.org/10.5194/bg-19-1813-2022, https://doi.org/10.5194/bg-19-1813-2022, 2022
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This study presents a new individual-based vegetation model to investigate salinity control on mangrove productivity. The model incorporates plant hydraulics and tree competition and predicts unique and complex patterns of mangrove forest structures that vary across soil salinity gradients. The presented model does not hold an empirical expression of salinity influence on productivity and thus may provide a better understanding of mangrove forest dynamics in future climate change.
Coulson A. Lantz, William Leggat, Jessica L. Bergman, Alexander Fordyce, Charlotte Page, Thomas Mesaglio, and Tracy D. Ainsworth
Biogeosciences, 19, 891–906, https://doi.org/10.5194/bg-19-891-2022, https://doi.org/10.5194/bg-19-891-2022, 2022
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Coral bleaching events continue to drive the degradation of coral reefs worldwide. In this study we measured rates of daytime coral reef community calcification and photosynthesis during a reef-wide bleaching event. Despite a measured decline in coral health across several taxa, there was no change in overall daytime community calcification and photosynthesis. These findings highlight potential limitations of these community-level metrics to reflect actual changes in coral health.
Hyewon Heather Kim, Jeff S. Bowman, Ya-Wei Luo, Hugh W. Ducklow, Oscar M. Schofield, Deborah K. Steinberg, and Scott C. Doney
Biogeosciences, 19, 117–136, https://doi.org/10.5194/bg-19-117-2022, https://doi.org/10.5194/bg-19-117-2022, 2022
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Heterotrophic marine bacteria are tiny organisms responsible for taking up organic matter in the ocean. Using a modeling approach, this study shows that characteristics (taxonomy and physiology) of bacteria are associated with a subset of ecological processes in the coastal West Antarctic Peninsula region, a system susceptible to global climate change. This study also suggests that bacteria will become more active, in particular large-sized cells, in response to changing climates in the region.
Alice E. Webb, Didier M. de Bakker, Karline Soetaert, Tamara da Costa, Steven M. A. C. van Heuven, Fleur C. van Duyl, Gert-Jan Reichart, and Lennart J. de Nooijer
Biogeosciences, 18, 6501–6516, https://doi.org/10.5194/bg-18-6501-2021, https://doi.org/10.5194/bg-18-6501-2021, 2021
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The biogeochemical behaviour of shallow reef communities is quantified to better understand the impact of habitat degradation and species composition shifts on reef functioning. The reef communities investigated barely support reef functions that are usually ascribed to conventional coral reefs, and the overall biogeochemical behaviour is found to be similar regardless of substrate type. This suggests a decrease in functional diversity which may therefore limit services provided by this reef.
Emmanuel Devred, Andrea Hilborn, and Cornelia Elizabeth den Heyer
Biogeosciences, 18, 6115–6132, https://doi.org/10.5194/bg-18-6115-2021, https://doi.org/10.5194/bg-18-6115-2021, 2021
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A theoretical model of grey seal seasonal abundance on Sable Island (SI) coupled with chlorophyll-a concentration [chl-a] measured by satellite revealed the impact of seal nitrogen fertilization on the surrounding waters of SI, Canada. The increase in seals from about 100 000 in 2003 to about 360 000 in 2018 during the breeding season is consistent with an increase in [chl-a] leeward of SI. The increase in seal abundance explains 8 % of the [chl-a] increase.
Julie Meilland, Michael Siccha, Maike Kaffenberger, Jelle Bijma, and Michal Kucera
Biogeosciences, 18, 5789–5809, https://doi.org/10.5194/bg-18-5789-2021, https://doi.org/10.5194/bg-18-5789-2021, 2021
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Planktonic foraminifera population dynamics has long been assumed to be controlled by synchronous reproduction and ontogenetic vertical migration (OVM). Due to contradictory observations, this concept became controversial. We here test it in the Atlantic ocean for four species of foraminifera representing the main clades. Our observations support the existence of synchronised reproduction and OVM but show that more than half of the population does not follow the canonical trajectory.
Federica Maggioni, Mireille Pujo-Pay, Jérome Aucan, Carlo Cerrano, Barbara Calcinai, Claude Payri, Francesca Benzoni, Yves Letourneur, and Riccardo Rodolfo-Metalpa
Biogeosciences, 18, 5117–5140, https://doi.org/10.5194/bg-18-5117-2021, https://doi.org/10.5194/bg-18-5117-2021, 2021
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Based on current experimental evidence, climate change will affect up to 90 % of coral reefs worldwide. The originality of this study arises from our recent discovery of an exceptional study site where environmental conditions (temperature, pH, and oxygen) are even worse than those forecasted for the future.
While these conditions are generally recognized as unfavorable for marine life, we found a rich and abundant coral reef thriving under such extreme environmental conditions.
Nisan Sariaslan and Martin R. Langer
Biogeosciences, 18, 4073–4090, https://doi.org/10.5194/bg-18-4073-2021, https://doi.org/10.5194/bg-18-4073-2021, 2021
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Analyses of foraminiferal assemblages from the Mamanguape mangrove estuary (northern Brazil) revealed highly diverse, species-rich, and structurally complex biotas. The atypical fauna resembles shallow-water offshore assemblages and are interpreted to be the result of highly saline ocean waters penetrating deep into the estuary. The findings contrast with previous studies, have implications for the fossil record, and provide novel perspectives for reconstructing mangrove environments.
Jutta E. Wollenburg, Jelle Bijma, Charlotte Cremer, Ulf Bickmeyer, and Zora Mila Colomba Zittier
Biogeosciences, 18, 3903–3915, https://doi.org/10.5194/bg-18-3903-2021, https://doi.org/10.5194/bg-18-3903-2021, 2021
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Cultured at in situ high-pressure conditions Cibicides and Cibicidoides taxa develop lasting ectoplasmic structures that cannot be retracted or resorbed. An ectoplasmic envelope surrounds their test and may protect the shell, e.g. versus carbonate aggressive bottom water conditions. Ectoplasmic roots likely anchor the specimens in areas of strong bottom water currents, trees enable them to elevate themselves above ground, and twigs stabilize and guide the retractable pseudopodial network.
Kumar Nimit
Biogeosciences, 18, 3631–3635, https://doi.org/10.5194/bg-18-3631-2021, https://doi.org/10.5194/bg-18-3631-2021, 2021
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The Indian Ocean Rim hosts many of the underdeveloped and emerging economies that depend on ocean resources for the livelihood of millions. Operational ocean information services cater to the requirements of resource managers and end-users to efficiently harness resources, mitigate threats and ensure safety. This paper outlines existing tools and explores the ongoing research that has the potential to convert the findings into operational services in the near- to midterm.
Finn Mielck, Rune Michaelis, H. Christian Hass, Sarah Hertel, Caroline Ganal, and Werner Armonies
Biogeosciences, 18, 3565–3577, https://doi.org/10.5194/bg-18-3565-2021, https://doi.org/10.5194/bg-18-3565-2021, 2021
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Marine sand mining is becoming more and more important to nourish fragile coastlines that face global change. We investigated the largest sand extraction site in the German Bight. The study reveals that after more than 35 years of mining, the excavation pits are still detectable on the seafloor while the sediment composition has largely changed. The organic communities living in and on the seafloor were strongly decimated, and no recovery is observable towards previous conditions.
Oscar E. Romero, Simon Ramondenc, and Gerhard Fischer
Biogeosciences, 18, 1873–1891, https://doi.org/10.5194/bg-18-1873-2021, https://doi.org/10.5194/bg-18-1873-2021, 2021
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Upwelling intensity along NW Africa varies on the interannual to decadal timescale. Understanding its changes is key for the prediction of future changes of CO2 sequestration in the northeastern Atlantic. Based on a multiyear (1988–2009) sediment trap experiment at the site CBmeso, fluxes and the species composition of the diatom assemblage are presented. Our data help in establishing the scientific basis for forecasting and modeling future states of this ecosystem and its decadal changes.
Katharine T. Bigham, Ashley A. Rowden, Daniel Leduc, and David A. Bowden
Biogeosciences, 18, 1893–1908, https://doi.org/10.5194/bg-18-1893-2021, https://doi.org/10.5194/bg-18-1893-2021, 2021
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Turbidity flows – underwater avalanches – are large-scale physical disturbances believed to have profound impacts on productivity and diversity of benthic communities in the deep sea. We reviewed published studies and found that current evidence for changes in productivity is ambiguous at best, but the influence on regional and local diversity is clearer. We suggest study design criteria that may lead to a better understanding of large-scale disturbance effects on deep-sea benthos.
Phillip Williamson, Hans-Otto Pörtner, Steve Widdicombe, and Jean-Pierre Gattuso
Biogeosciences, 18, 1787–1792, https://doi.org/10.5194/bg-18-1787-2021, https://doi.org/10.5194/bg-18-1787-2021, 2021
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The reliability of ocean acidification research was challenged in early 2020 when a high-profile paper failed to corroborate previously observed impacts of high CO2 on the behaviour of coral reef fish. We now know the reason why: the
replicatedstudies differed in many ways. Open-minded and collaborative assessment of all research results, both negative and positive, remains the best way to develop process-based understanding of the impacts of ocean acidification on marine organisms.
Michael Lintner, Bianca Lintner, Wolfgang Wanek, Nina Keul, and Petra Heinz
Biogeosciences, 18, 1395–1406, https://doi.org/10.5194/bg-18-1395-2021, https://doi.org/10.5194/bg-18-1395-2021, 2021
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Foraminifera are unicellular marine organisms that play an important role in the marine element cycle. Changes of environmental parameters such as salinity or temperature have a significant impact on the faunal assemblages. Our experiments show that changes in salinity immediately influence the foraminiferal activity. Also the light regime has a significant impact on carbon or nitrogen processing in foraminifera which contain no kleptoplasts.
Michele Casini, Martin Hansson, Alessandro Orio, and Karin Limburg
Biogeosciences, 18, 1321–1331, https://doi.org/10.5194/bg-18-1321-2021, https://doi.org/10.5194/bg-18-1321-2021, 2021
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In the past 20 years the condition of the eastern Baltic cod has dropped, with large implications for the fishery. Our results show that simultaneously the cod population has moved deeper while low-oxygenated waters detrimental for cod growth have become shallower. Cod have thus dwelled more in detrimental waters, explaining the drop in its condition. This study, using long-term fish and hydrological monitoring data, evidences the impact of deoxygenation on fish biology and fishing.
Elizabeth D. LaBone, Kenneth A. Rose, Dubravko Justic, Haosheng Huang, and Lixia Wang
Biogeosciences, 18, 487–507, https://doi.org/10.5194/bg-18-487-2021, https://doi.org/10.5194/bg-18-487-2021, 2021
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The hypoxic zone is an area of low dissolved oxygen (DO) in the Gulf of Mexico. Fish can be killed by exposure to hypoxia and can be negatively impacted by exposure to low, nonlethal DO concentrations (sublethal DO). We found that high sublethal area resulted in higher exposure and DO variability had a small effect on exposure. There was a large variation in exposure among individuals, which when combined with spatial variability of DO, can result in an underestimation of exposure when averaged.
Svenja Reents, Peter Mueller, Hao Tang, Kai Jensen, and Stefanie Nolte
Biogeosciences, 18, 403–411, https://doi.org/10.5194/bg-18-403-2021, https://doi.org/10.5194/bg-18-403-2021, 2021
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By conducting a flooding experiment with two genotypes of the salt-marsh grass Elymus athericus, we show considerable differences in biomass response to flooding within the same species. As biomass production plays a major role in sedimentation processes and thereby salt-marsh accretion, we emphasise the importance of taking intraspecific differences into account when evaluating ecosystem resilience to accelerated sea level rise.
Cara Nissen and Meike Vogt
Biogeosciences, 18, 251–283, https://doi.org/10.5194/bg-18-251-2021, https://doi.org/10.5194/bg-18-251-2021, 2021
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Using a regional Southern Ocean ecosystem model, we find that the relative importance of Phaeocystis and diatoms at high latitudes is controlled by iron and temperature variability, with light levels controlling the seasonal succession in coastal areas. Yet, biomass losses via aggregation and grazing matter as well. We show that the seasonal succession of Phaeocystis and diatoms impacts the seasonality of carbon export fluxes with ramifications for nutrient cycling and food web dynamics.
Jiangtao Li, Lingyuan Gu, Shijie Bai, Jie Wang, Lei Su, Bingbing Wei, Li Zhang, and Jiasong Fang
Biogeosciences, 18, 113–133, https://doi.org/10.5194/bg-18-113-2021, https://doi.org/10.5194/bg-18-113-2021, 2021
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Few studies have focused on the particle-attached (PA) and free-living (FL) microbes of the deep ocean. Here we determined PA and FL microbial communities along depth profiles of the SCS. PA and FL fractions accommodated divergent microbial compositions, and most of them are potentially generalists with PA and FL dual lifestyles. A potential vertical connectivity between surface-specific microbes and those in the deep ocean was indicated, likely through microbial attachment to sinking particles.
Saskia Brix, Karen J. Osborn, Stefanie Kaiser, Sarit B. Truskey, Sarah M. Schnurr, Nils Brenke, Marina Malyutina, and Pedro Martinez Arbizu
Biogeosciences, 17, 6163–6184, https://doi.org/10.5194/bg-17-6163-2020, https://doi.org/10.5194/bg-17-6163-2020, 2020
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The Clarion–Clipperton Fracture Zone (CCZ) located in the Pacific is commercially the most important area of proposed manganese nodule mining. Extraction of this will influence the life and distribution of small deep-sea invertebrates like peracarid crustaceans, of which >90 % are undescribed species new to science. We are doing a species delimitation approach as baseline for an ecological interpretation of species distribution and discuss the results in light of future deep-sea conservation.
Amal Jayakumar and Bess B. Ward
Biogeosciences, 17, 5953–5966, https://doi.org/10.5194/bg-17-5953-2020, https://doi.org/10.5194/bg-17-5953-2020, 2020
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Diversity and community composition of nitrogen-fixing microbes in the three main oxygen minimum zones of the world ocean were investigated using nifH clone libraries. Representatives of three main clusters of nifH genes were detected. Sequences were most diverse in the surface waters. The most abundant OTUs were affiliated with Alpha- and Gammaproteobacteria. The sequences were biogeographically distinct and the dominance of a few OTUs was commonly observed in OMZs in this (and other) studies.
Guillermo Feliú, Marc Pagano, Pamela Hidalgo, and François Carlotti
Biogeosciences, 17, 5417–5441, https://doi.org/10.5194/bg-17-5417-2020, https://doi.org/10.5194/bg-17-5417-2020, 2020
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The impact of Saharan dust deposition events on the Mediterranean Sea ecosystem was studied during a basin-scale survey (PEACETIME cruise, May–June 2017). Short-term responses of the zooplankton community were observed after episodic dust deposition events, highlighting the impact of these events on productivity up to the zooplankton level in the poorly fertilized pelagic ecosystems of the southern Mediterranean Sea.
Douglas Lessa, Raphaël Morard, Lukas Jonkers, Igor M. Venancio, Runa Reuter, Adrian Baumeister, Ana Luiza Albuquerque, and Michal Kucera
Biogeosciences, 17, 4313–4342, https://doi.org/10.5194/bg-17-4313-2020, https://doi.org/10.5194/bg-17-4313-2020, 2020
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We observed that living planktonic foraminifera had distinct vertically distributed communities across the Subtropical South Atlantic. In addition, a hierarchic alternation of environmental parameters was measured to control the distribution of planktonic foraminifer's species depending on the water depth. This implies that not only temperature but also productivity and subsurface processes are signed in fossil assemblages, which could be used to perform paleoceanographic reconstructions.
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Short summary
Michaelis–Menten kinetics were determined for alkaline phosphatase, aminopeptidase and β-glucosidase in the Mediterranean Sea. Although the ectoenzymatic-hydrolysis contribution to heterotrophic prokaryotic needs was high in terms of N, it was low in terms of C. This study points out the biases in interpretation of the relative differences in activities among the three tested enzymes in regard to the choice of added concentrations of fluorogenic substrates.
Michaelis–Menten kinetics were determined for alkaline phosphatase, aminopeptidase and...
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