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Impact of interactions between microorganisms on iron and carbon recycling in the Southern Ocean : consequences for iron limitation

English title Impact of interactions between microorganisms on iron and carbon recycling in the Southern Ocean : consequences for iron limitation
Applicant Hassler Christel
Number 166197
Funding scheme SNSF Professorships
Research institution Institut F.-A. Forel Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Oceanography
Start/End 01.01.2017 - 30.06.2019
Approved amount 804'745.00
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All Disciplines (3)

Discipline
Oceanography
Environmental Research
Biochemistry

Keywords (8)

iron limitation; DOC; bacteria; Southern Ocean; phytoplankton; recycling; EPS; bioavailability

Lay Summary (French)

Lead
La pompe à carbone dans l'océan austral
Lay summary
L’océan austral joue un rôle critique pour le cycle global du carbone et donc pour la régulation du climat. Néanmoins, dans cette région, le cycle du carbone est largement influencé par le fer – un élément nutritif limitant. Afin de mieux comprendre comment la matière organique contrôle la biogéochimie du fer, nous allons concentrer puis caractériser cette matière organique dans des zones contrastées. Ce projet propose également de revisiter le rôle des bactéries et des virus sur les transformations, le recyclage et l’export d’éléments clefs tels le carbone et le fer. Dans un premier temps, la biodiversité bactérienne et virale sera mesurée lors de deux campagnes océanographiques, constituant ainsi les premières données sur les virus autour du Pôle Sud. Nous isolerons et ramènerons des souches bactériennes et virales afin de les étudier plus avant en laboratoire et explorer les interactions entre bactéries, matière organique, fer et virus. Ces souches seront également partagées librement dans le but de stimuler la recherche Antarctique, générant ainsi des avancées en dehors du domaine de l’environnement.
Direct link to Lay Summary Last update: 23.03.2017

Lay Summary (English)

Lead
The carbon pump in the Southern Ocean
Lay summary

Processes occurring in the Southern Ocean are paramount for Earth's climate. This projects aims to improve our understanding of the functioning of the Southern Ocean and its role in the regulation of our climate. Here we are centered on two pivotal regulators: iron chemistry and dissolved organic carbon, both of with are controlling how microorganisms affect our climate. Here we will simultaneously study the biochemistry of iron, organic carbon and its role for microorganisms’ (phytoplankton, bacteria and viruses) mediated carbon pumps. This will be achieved by combining experiments at sea and in the laboratory. Here, we will isolate and characterize organic carbon present in iron-limited and iron replete regions chosen to represent the biochemical variability encountered across the Southern Ocean. We will characterize these compounds in order to understand their nature and role in iron chemistry and microorganisms activity. An extensive and unique analytical matrix is proposed to resolve key properties and functional groups in organic compounds as well as its iron binding properties, likely identifying, for the first time, the “dark matter” constituting these compounds involved in Fe binding as well as binding mechanism. This project also explores a novel research area: the role of viruses in the degradation of marine organic carbon and its impact for both the biological and the microbial pumps. Major breakthrough in the field of marine biogeochemistry is thus expected as well as solid contributions to international research programs. Being related to climate, ecosystem functioning and biodiversity, this project benefits to the scientific community at large.

Direct link to Lay Summary Last update: 23.03.2017

Responsible applicant and co-applicants

Employees

Publications

Publication
Chromium biogeochemistry and stable isotope distribution in the Southern Ocean
Rickli Jörg, Janssen David J., Hassler Christel, Ellwood Michael J., Jaccard Samuel L. (2019), Chromium biogeochemistry and stable isotope distribution in the Southern Ocean, in Geochimica et Cosmochimica Acta, 1.
Iron isotope transformations in the meromictic Lake Cadagno
Ellwood Michael J., Hassler Christel, Moisset Sophie, Pascal Ludovic, Danza Francesco, Peduzzi Sandro, Tonolla Mauro, Vance Derek (2019), Iron isotope transformations in the meromictic Lake Cadagno, in Geochimica et Cosmochimica Acta, 255, 205-221.
Towards the development of a new generation of whole‐cell bioreporters to sense iron bioavailability in oceanic systems – learning from the case of Synechococcus sp. PCC 7002 iron bioreporter
Blanco‐Ameijeiras Sonia, Cabanes Damien J. E., Hassler Christel S. (2019), Towards the development of a new generation of whole‐cell bioreporters to sense iron bioavailability in oceanic systems – learning from the case of Synechococcus sp. PCC 7002 iron bioreporter, in Journal of Applied Microbiology, jam.14277-jam.14277.
Response of phytoplankton from the metalimnetic chlorophyll maximum to macro- and micro-nutrients amendments in Lake Geneva
Moisset Sophie A.M., Cabanes Damien J.E., Blanco-Ameijeiras Sonia, Hassler Christel S. (2019), Response of phytoplankton from the metalimnetic chlorophyll maximum to macro- and micro-nutrients amendments in Lake Geneva, in Journal of Great Lakes Research, 45(2), 290-299.
Investigating the fate of copper in a laboratory‐based toxicity test with embryos of Mytilus galloprovincialis : Copper mass balance of a closed bioassay
Zitoun Rebecca, Hassler Christel, Clearwater Susan J., Thompson Karen J., Albert Anathea, Sander Sylvia G. (2019), Investigating the fate of copper in a laboratory‐based toxicity test with embryos of Mytilus galloprovincialis : Copper mass balance of a closed bioassay, in Environmental Toxicology and Chemistry, 38(3), 561-574.
Copper toxicity to blue mussel embryos (Mytilus galloprovincialis)
Zitoun Rebecca, Clearwater Susan J., Hassler Christel, Thompson Karen J., Albert Anathea, Sander Sylvia G. (2019), Copper toxicity to blue mussel embryos (Mytilus galloprovincialis), in Science of The Total Environment, 653, 300-314.
A database of chlorophyll a in Australian waters
Davies Claire H., Ajani Penelope, Armbrecht Linda, Atkins Natalia, Baird Mark E., Beard Jason, Bonham Pru, Burford Michele, Clementson Lesley, Coad Peter, Crawford Christine, Dela-Cruz Jocelyn, Doblin Martina A., Edgar Steven, Eriksen Ruth, Everett Jason D., Furnas Miles, Harrison Daniel P., Hassler Christel, Henschke Natasha, Hoenner Xavier, Ingleton Tim, Jameson Ian, Keesing John, et al. (2018), A database of chlorophyll a in Australian waters, in Scientific Data, 5(1), 180018-180018.
Marine microbial metagenomes sampled across space and time
Biller Steven J., Berube Paul M., Dooley Keven, Williams Madeline, Satinsky Brandon M., Hackl Thomas, Hogle Shane L., Coe Allison, Bergauer Kristin, Bouman Heather A., Browning Thomas J., De Corte Daniele, Hassler Christel, Hulston Debbie, Jacquot Jeremy E., Maas Elizabeth W., Reinthaler Thomas, Sintes Eva, Yokokawa Taichi, Chisholm Sallie W. (2018), Marine microbial metagenomes sampled across space and time, in Scientific Data, 5(1), 180176-180176.
Single cell genomes of Prochlorococcus, Synechococcus, and sympatric microbes from diverse marine environments
Berube Paul M., Biller Steven J., Hackl Thomas, Hogle Shane L., Satinsky Brandon M., Becker Jamie W., Braakman Rogier, Collins Sara B., Kelly Libusha, Berta-Thompson Jessie, Coe Allison, Bergauer Kristin, Bouman Heather A., Browning Thomas J., De Corte Daniele, Hassler Christel, Hulata Yotam, Jacquot Jeremy E., Maas Elizabeth W., Reinthaler Thomas, Sintes Eva, Yokokawa Taichi, Lindell Debbie, Stepanauskas Ramunas, et al. (2018), Single cell genomes of Prochlorococcus, Synechococcus, and sympatric microbes from diverse marine environments, in Scientific Data, 5(1), 180154-180154.
Elemental Stoichiometry and Photophysiology Regulation of Synechococcus sp. PCC7002 Under Increasing Severity of Chronic Iron Limitation
Blanco-Ameijeiras Sonia, Moisset Sophie A M, Trimborn Scarlett, Campbell Douglas A, Heiden Jasmin P, Hassler Christel S (2018), Elemental Stoichiometry and Photophysiology Regulation of Synechococcus sp. PCC7002 Under Increasing Severity of Chronic Iron Limitation, in Plant and Cell Physiology, 59(9), 1803-1816.
The GEOTRACES Intermediate Data Product 2017
Schlitzer Reiner, Anderson Robert F., Dodas Elena Masferrer, Lohan Maeve, Geibert Walter, Tagliabue Alessandro, Bowie Andrew, Jeandel Catherine, Maldonado Maria T., Landing William M., Cockwell Donna, Abadie Cyril, Abouchami Wafa, Achterberg Eric P., Agather Alison, Aguliar-Islas Ana, van Aken Hendrik M., Andersen Morten, Archer Corey, Auro Maureen, de Baar Hein J., Baars Oliver, Baker Alex R., Bakker Karel, et al. (2018), The GEOTRACES Intermediate Data Product 2017, in Chemical Geology, 493, 210-223.
Insights Into the Biogeochemical Cycling of Iron, Nitrate, and Phosphate Across a 5,300 km South Pacific Zonal Section (153°E-150°W)
Ellwood Michael J., Bowie Andrew R., Baker Alex, Gault-Ringold Melanie, Hassler Christel, Law Cliff S., Maher William A., Marriner Andrew, Nodder Scott, Sander Sylvia, Stevens Craig, Townsend Ashley, van der Merwe Pier, Woodward E. Malcolm S., Wuttig Kathrin, Boyd Philip W. (2018), Insights Into the Biogeochemical Cycling of Iron, Nitrate, and Phosphate Across a 5,300 km South Pacific Zonal Section (153°E-150°W), in Global Biogeochemical Cycles, 32(2), 187-207.
Assessing the Dynamic of organic aerosols over the North Atlantic Ocean
CH7 Kasparian J. Hassler C.S. et al. (2017), Assessing the Dynamic of organic aerosols over the North Atlantic Ocean, in Nature Scientific Reports. , 7, 45476.
Dissolved zinc isotope as a tool to investigate zinc biogeochemical cycling in the Tasman Sea.
CH6 Moneesha S. Ellwood M.J.E. Sinoir M. Hassler C.S. (2017), Dissolved zinc isotope as a tool to investigate zinc biogeochemical cycling in the Tasman Sea., in Marine Chemistry, 192, 1.
First evaluation on the role of salp fecal pellets on iron biogeochemistry.
CH9 Cabanes D.J.E. Norman L. Santos-Echeandia J. Iversen M.H. Trimborn S. Laglera L.M. H (2017), First evaluation on the role of salp fecal pellets on iron biogeochemistry., in Frontiers in Marine Sciences, 1.
Iron sources alter the response of Southern Ocean phytoplankton to ocean acidification.
CH4 Trimborn S. Brenneis T. Hoppe C.J.M. Laglera L. Norman L. Santos-Echeandia J. Völkner C. (2017), Iron sources alter the response of Southern Ocean phytoplankton to ocean acidification., in Marine Ecology Progress Series, 578, 35.
Long-term acclimation to iron limitation reveals new insights in metabolism regulation of Synechococcus sp. PCC7002.
CH5 Blanco-Ameijeiras S. Cosi C. Hassler C.S. (2017), Long-term acclimation to iron limitation reveals new insights in metabolism regulation of Synechococcus sp. PCC7002., in Frontier Marine Sciences, 1.
Organic ligands – A key control of trace metal biogeochemistry in the ocean.
Buck K.N. Lohan M.C. Sander S.G. Hassler C. Pizeta I. (2017), Organic ligands – A key control of trace metal biogeochemistry in the ocean., in Frontier in Marine Science, 1.
Using a regional classification to provide a more inclusive examination of the ocean biogeochemistry of iron-binding ligands
CH8 Hassler C.S. van den Berg C. Boyd P.W (2017), Using a regional classification to provide a more inclusive examination of the ocean biogeochemistry of iron-binding ligands, in Frontiers in Marine Sciences, 1.

Collaboration

Group / person Country
Types of collaboration
RMN-RPE-Masse, University of Brest France (Europe)
- Publication
CERMAV, CNRS France (Europe)
- Publication
INRA France (Europe)
- Publication
- Research Infrastructure
- Exchange of personnel
MIT United States of America (North America)
- Publication
Duhaime Lab / Michigan University United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
Alfred Wengener Institute Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
School of Pharmacology, University of Geneva Switzerland (Europe)
- Publication
- Research Infrastructure
Department of Chemistry, University of Otago New Zealand (Oceania)
- Publication
Plymouth University Great Britain and Northern Ireland (Europe)
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
SCAR and IASC - Polar 2018 Poster In a Search for Ancient Marine Virus and Bacteria in Lake Cadagno, Switzerland 24.06.2018 Davos, Switzerland Fourquez Marion; Hassler Christel;
SCAR and IASC- Polar 2018 Poster ACBC - Antarctic Circumnavigation Bacterial Collection: Highway to Knowledge 24.06.2018 Davos, Switzerland Hassler Christel; Fourquez Marion;
SCAR and IASC - POlar 2018 Poster Tracing the Iron Cycle in the Southern Ocean during the ACE Voyage 24.06.2018 Davos, Switzerland Hassler Christel; Cabanes Damien;
SCAR and IASC - Polar 2018 Individual talk Recycling of Iron Binding Ligands in the Context of Ocean Circulation 24.06.2018 Davos, Switzerland Cabanes Damien; Hassler Christel;
SCAR and IASC- Poilar 2018 Talk given at a conference Riding on the “Ferrous Wave”— Bacteria Are Outcompeted by Small Phytoplankton 24.06.2018 Davos, Switzerland Fourquez Marion; Hassler Christel;
SCAR and IASC - Polar 2018 Talk given at a conference Combined Effects of Light, CO2 and Iron on Antarctic Phytoplankton 24.06.2018 Davos, Switzerland Hassler Christel;
Ocean Sciences Meeting Talk given at a conference How far can iron chemistry tell us about bioavailability in the Southern Ocean 12.02.2018 Portland, United States of America Hassler Christel; Cabanes Damien;
SCOR WorkGrop 151 FEMIP Individual talk What about the ligands 11.02.2018 Portland, United States of America Hassler Christel;
Swiss Polar Day Individual talk Polar Research and Teaching Activity from the University of Geneva 07.09.2017 WSL Zurich, Switzerland Hassler Christel;
SCAR Biology Symposium Talk given at a conference Iron bioavailability to iron-limited Southern Ocean phytoplankton : from the lab to the field 01.07.2017 Leuven, Belgium Hassler Christel;


Communication with the public

Communication Title Media Place Year
Media relations: radio, television L’importance du phytoplancton de l’océan Austral pour la, planète RTS CQFD Western Switzerland 2017
Media relations: radio, television 19h30 TJ RTS TV Western Switzerland 2017
Talks/events/exhibitions Australia-the defense of our oceans Western Switzerland International 2017
Media relations: print media, online media Fragile Antarctique La Liberté, Le courrier Western Switzerland 2017
Media relations: print media, online media Le plastique, fléau pour le Pôle Sud L'express, La côte, Le nouvelliste Western Switzerland 2017
Media relations: radio, television Prise de Terre RTS Western Switzerland 2017
Video/Film Thalassa, FR3 et TV5 Monde International 2017
Media relations: radio, television TJ 9h30 4 February RTS TV Western Switzerland 2017
Video/Film TV Al Jazeera EarthRise International 2017
Media relations: radio, television Une vie de manchot RTS Prise de Terre Western Switzerland 2017

Associated projects

Number Title Start Funding scheme
138955 Novel technologies to reveal the impacts of nutrient limitation in aquatic systems: from biodiversity to biogeochemical cycles 01.01.2013 SNSF Professorships

Abstract

The Southern Ocean (SO) plays a critical role on atmospheric CO2 sink mediated by the physical, biological and microbial pumps and thus affects our climate. The SO is the largest oceanic iron-limited region, and unsurprisingly it has been extensively studied. However, how iron limitation takes places and its consequences for the efficiency of the biological carbon pump mediated by phytoplankton remain mostly unresolved. The lack of understanding of the link between iron chemistry and its bioavailability as well as the key drivers and processes at play, significantly prevents advances in this research area. Because iron is mostly associated with organic ligands and limits the growth of phytoplankton in most of the SO, the biogeochemistry of Fe and carbon are closely inter-related. Moreover, the labile dissolved organic compounds excreted by phytoplankton are rapidly consumed by heterotrophic bacteria to fuel carbon export mediated by the microbial carbon pump. It is thus evident that both carbon pumps are inter-related with the production and recycling of organic carbon and bioavailable Fe acting as critical connectors in the SO. However, the link between these pumps is mostly conceptual and controlling mechanisms remain unknown. As this connection is critical for the functioning of this ecosystem including its footprint on our climate, it is urgent to learn how these pumps are connected and controlled.This project addresses specific aspects related to this major gap of knowledge by investigating pathways involved in the production/recycling of carbon and iron in surface water. This will be achieved by combining experiments at sea and in the laboratory. For this purpose, marine dissolved organic compounds (DOC) from various origins will be isolated and characterized. Here, we will isolate and characterize DOC from iron-limited and iron replete regions chosen to represent the biochemical variability encountered across the SO. Moreover, DOC produced by key biological players from the SO will be isolated and studied; including DOC excreted by bacteria, phytoplankton and grazers. Moreover, DOC sensitivity to photo- and viral degradations - two important transformation pathways - will be quantified. An extensive and unique analytical matrix is proposed to resolve key properties and functional groups in DOC as well as its iron binding properties, likely identifying, for the first time, the “dark matter” constituting DOC compounds involved in Fe binding as well as binding mechanism. The comparison of the various DOC compositions will identify whether a unique chemical traceable signature is associated with specific origin or transformation pathways. The impact on the microbial pump will be inferred from DOC lability whereas the impact on the biological pump will be inferred from iron bioavailability (55Fe bioaccumulation), pigments, photo-physiology and POC analyses.Finally, this project explores a novel research area: the role of viruses in the degradation of marine DOC and its impact for both the biological and the microbial pumps. Marine viruses constitutively bear enzymes that are efficient in passively degrading their hosts carbohydrates in solution, whose impact has never been addressed. Given the high concentration and diversity of viruses in the ocean, and the facts that carbohydrate constitute up to 50 % of marine DOC and can affect iron chemistry, this study might totally revisit the role of viruses in marine biogeochemistry and result in seminal publications. Important collaborative efforts on highly specialised techniques are put at play to solve the complexity of marine DOC and Fe-binding ligands. Major breakthrough in the field of marine biogeochemistry is thus expected as well as solid contributions to international research programs, such as SCOR and GEOTRACES. Being related to climate, ecosystem functioning and biodiversity, this project benefits to the scientific community at large.
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