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Klawonn I, Van den Wyngaert S, Iversen MH, Walles TJW, Flintrop CM, Cisternas-Novoa C, Nejstgaard JC, Kagami M, Grossart HP. Fungal parasitism on diatoms alters formation and bio-physical properties of sinking aggregates. Commun Biol 2023; 6:206. [PMID: 36810576 PMCID: PMC9944279 DOI: 10.1038/s42003-023-04453-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 01/10/2023] [Indexed: 02/24/2023] Open
Abstract
Phytoplankton forms the base of aquatic food webs and element cycling in diverse aquatic systems. The fate of phytoplankton-derived organic matter, however, often remains unresolved as it is controlled by complex, interlinked remineralization and sedimentation processes. We here investigate a rarely considered control mechanism on sinking organic matter fluxes: fungal parasites infecting phytoplankton. We demonstrate that bacterial colonization is promoted 3.5-fold on fungal-infected phytoplankton cells in comparison to non-infected cells in a cultured model pathosystem (diatom Synedra, fungal microparasite Zygophlyctis, and co-growing bacteria), and even ≥17-fold in field-sampled populations (Planktothrix, Synedra, and Fragilaria). Additional data obtained using the Synedra-Zygophlyctis model system reveals that fungal infections reduce the formation of aggregates. Moreover, carbon respiration is 2-fold higher and settling velocities are 11-48% lower for similar-sized fungal-infected vs. non-infected aggregates. Our data imply that parasites can effectively control the fate of phytoplankton-derived organic matter on a single-cell to single-aggregate scale, potentially enhancing remineralization and reducing sedimentation in freshwater and coastal systems.
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Affiliation(s)
- Isabell Klawonn
- Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775, Stechlin, Germany.
- Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), 18119, Rostock, Germany.
| | - Silke Van den Wyngaert
- Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775, Stechlin, Germany
- Department of Biology, University of Turku, 20014, Turku, Finland
| | - Morten H Iversen
- Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research, 27570, Bremerhaven, Germany
- Centre for Marine Environmental Sciences (MARUM) and University of Bremen, 28359, Bremen, Germany
| | - Tim J W Walles
- Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775, Stechlin, Germany
| | - Clara M Flintrop
- Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research, 27570, Bremerhaven, Germany
- Centre for Marine Environmental Sciences (MARUM) and University of Bremen, 28359, Bremen, Germany
- The Inter-University Institute for Marine Sciences in Eilat, Eilat, 8810302, Israel
| | - Carolina Cisternas-Novoa
- Helmholtz Centre for Ocean Research (GEOMAR), 24148, Kiel, Germany
- Ocean Sciences Centre, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada
| | - Jens C Nejstgaard
- Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775, Stechlin, Germany
| | - Maiko Kagami
- Faculty of Science, Toho University, Funabashi, Chiba, 274‑8510, Japan
- Faculty of Environment and Information Sciences, Yokohama National University, Yokohama, Kanagawa, 240‑8502, Japan
| | - Hans-Peter Grossart
- Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775, Stechlin, Germany
- Institute of Biochemistry and Biology, Potsdam University, 14469, Potsdam, Germany
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2
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Roik A, Reverter M, Pogoreutz C. A roadmap to understanding diversity and function of coral reef-associated fungi. FEMS Microbiol Rev 2022; 46:fuac028. [PMID: 35746877 PMCID: PMC9629503 DOI: 10.1093/femsre/fuac028] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/01/2022] [Accepted: 06/14/2022] [Indexed: 01/09/2023] Open
Abstract
Tropical coral reefs are hotspots of marine productivity, owing to the association of reef-building corals with endosymbiotic algae and metabolically diverse bacterial communities. However, the functional importance of fungi, well-known for their contribution to shaping terrestrial ecosystems and global nutrient cycles, remains underexplored on coral reefs. We here conceptualize how fungal functional traits may have facilitated the spread, diversification, and ecological adaptation of marine fungi on coral reefs. We propose that functions of reef-associated fungi may be diverse and go beyond their hitherto described roles of pathogens and bioeroders, including but not limited to reef-scale biogeochemical cycles and the structuring of coral-associated and environmental microbiomes via chemical mediation. Recent technological and conceptual advances will allow the elucidation of the physiological, ecological, and chemical contributions of understudied marine fungi to coral holobiont and reef ecosystem functioning and health and may help provide an outlook for reef management actions.
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Affiliation(s)
- Anna Roik
- Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, Ammerländer Heerstraße 231, 26129 Oldenburg, Germany
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Wilhelmshaven, 26046, Germany
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Miriam Reverter
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg, Wilhelmshaven, 26046, Germany
- School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, United Kingdom
| | - Claudia Pogoreutz
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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3
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Laundon D, Chrismas N, Bird K, Thomas S, Mock T, Cunliffe M. A cellular and molecular atlas reveals the basis of chytrid development. eLife 2022; 11:e73933. [PMID: 35227375 PMCID: PMC8887899 DOI: 10.7554/elife.73933] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 02/01/2022] [Indexed: 12/26/2022] Open
Abstract
The chytrids (phylum Chytridiomycota) are a major fungal lineage of ecological and evolutionary importance. Despite their importance, many fundamental aspects of chytrid developmental and cell biology remain poorly understood. To address these knowledge gaps, we combined quantitative volume electron microscopy and comparative transcriptome profiling to create an 'atlas' of the cellular and molecular basis of the chytrid life cycle, using the model chytrid Rhizoclosmatium globosum. From our developmental atlas, we describe the transition from the transcriptionally inactive free-swimming zoospore to the more biologically complex germling, and show that lipid processing is multifaceted and dynamic throughout the life cycle. We demonstrate that the chytrid apophysis is a compartmentalised site of high intracellular trafficking, linking the feeding/attaching rhizoids to the reproductive zoosporangium, and constituting division of labour in the chytrid cell plan. We provide evidence that during zoosporogenesis, zoospores display amoeboid morphologies and exhibit endocytotic cargo transport from the interstitial maternal cytoplasm. Taken together, our results reveal insights into chytrid developmental biology and provide a basis for future investigations into non-dikaryan fungal cell biology.
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Affiliation(s)
- Davis Laundon
- Marine Biological Association, The Laboratory, Citadel HillPlymouthUnited Kingdom
- School of Environmental Sciences, University of East AngliaNorwichUnited Kingdom
| | - Nathan Chrismas
- Marine Biological Association, The Laboratory, Citadel HillPlymouthUnited Kingdom
| | - Kimberley Bird
- Marine Biological Association, The Laboratory, Citadel HillPlymouthUnited Kingdom
| | - Seth Thomas
- Marine Biological Association, The Laboratory, Citadel HillPlymouthUnited Kingdom
| | - Thomas Mock
- School of Environmental Sciences, University of East AngliaNorwichUnited Kingdom
| | - Michael Cunliffe
- Marine Biological Association, The Laboratory, Citadel HillPlymouthUnited Kingdom
- School of Biological and Marine Sciences, University of PlymouthPlymouthUnited Kingdom
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4
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Ilicic D, Grossart HP. Basal Parasitic Fungi in Marine Food Webs-A Mystery Yet to Unravel. J Fungi (Basel) 2022; 8:114. [PMID: 35205868 PMCID: PMC8874645 DOI: 10.3390/jof8020114] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 01/20/2022] [Accepted: 01/25/2022] [Indexed: 02/01/2023] Open
Abstract
Although aquatic and parasitic fungi have been well known for more than 100 years, they have only recently received increased awareness due to their key roles in microbial food webs and biogeochemical cycles. There is growing evidence indicating that fungi inhabit a wide range of marine habitats, from the deep sea all the way to surface waters, and recent advances in molecular tools, in particular metagenome approaches, reveal that their diversity is much greater and their ecological roles more important than previously considered. Parasitism constitutes one of the most widespread ecological interactions in nature, occurring in almost all environments. Despite that, the diversity of fungal parasites, their ecological functions, and, in particular their interactions with other microorganisms remain largely speculative, unexplored and are often missing from current theoretical concepts in marine ecology and biogeochemistry. In this review, we summarize and discuss recent research avenues on parasitic fungi and their ecological potential in marine ecosystems, e.g., the fungal shunt, and emphasize the need for further research.
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Affiliation(s)
- Doris Ilicic
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhütte 2, 16775 Stechlin, Germany;
| | - Hans-Peter Grossart
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhütte 2, 16775 Stechlin, Germany;
- Institute of Biochemistry and Biology, Potsdam University, Maulbeerallee 2, 14469 Potsdam, Germany
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5
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Kluge M, Wauthy M, Clemmensen KE, Wurzbacher C, Hawkes JA, Einarsdottir K, Rautio M, Stenlid J, Peura S. Declining fungal diversity in Arctic freshwaters along a permafrost thaw gradient. GLOBAL CHANGE BIOLOGY 2021; 27:5889-5906. [PMID: 34462999 DOI: 10.1111/gcb.15852] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/03/2021] [Indexed: 06/13/2023]
Abstract
Climate change-driven permafrost thaw has a strong influence on pan-Arctic regions, via, for example, the formation of thermokarst ponds. These ponds are hotspots of microbial carbon cycling and greenhouse gas production, and efforts have been put on disentangling the role of bacteria and archaea in recycling the increasing amounts of carbon arriving to the ponds from degrading watersheds. However, despite the well-established role of fungi in carbon cycling in the terrestrial environments, the interactions between permafrost thaw and fungal communities in Arctic freshwaters have remained unknown. We integrated data from 60 ponds in Arctic hydro-ecosystems, representing a gradient of permafrost integrity and spanning over five regions, namely Alaska, Greenland, Canada, Sweden, and Western Siberia. The results revealed that differences in pH and organic matter quality and availability were linked to distinct fungal community compositions and that a large fraction of the community represented unknown fungal phyla. Results display a 16%-19% decrease in fungal diversity, assessed by beta diversity, across ponds in landscapes with more degraded permafrost. At the same time, sites with similar carbon quality shared more species, aligning a shift in species composition with the quality and availability of terrestrial dissolved organic matter. We demonstrate that the degradation of permafrost has a strong negative impact on aquatic fungal diversity, likely via interactions with the carbon pool released from ancient deposits. This is expected to have implications for carbon cycling and climate feedback loops in the rapidly warming Arctic.
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Affiliation(s)
- Mariana Kluge
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Maxime Wauthy
- Département des sciences fondamentales, Université du Québec à Chicoutimi, Saguenay, Québec, Canada
- Centre for Northern Studies (CEN), Université Laval, Québec, Québec, Canada
| | | | - Christian Wurzbacher
- Chair of Urban Water Systems Engineering, Technical University of Munich, Garching, Germany
| | | | | | - Milla Rautio
- Département des sciences fondamentales, Université du Québec à Chicoutimi, Saguenay, Québec, Canada
- Centre for Northern Studies (CEN), Université Laval, Québec, Québec, Canada
- Group for Interuniversity Research in Limnology and Aquatic Environment (GRIL), Université de Montréal, Montréal, Québec, Canada
| | - Jan Stenlid
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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6
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Ramírez GA, Mara P, Sehein T, Wegener G, Chambers CR, Joye SB, Peterson RN, Philippe A, Burgaud G, Edgcomb VP, Teske AP. Environmental factors shaping bacterial, archaeal and fungal community structure in hydrothermal sediments of Guaymas Basin, Gulf of California. PLoS One 2021; 16:e0256321. [PMID: 34495995 PMCID: PMC8425543 DOI: 10.1371/journal.pone.0256321] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/03/2021] [Indexed: 01/04/2023] Open
Abstract
The flanking regions of Guaymas Basin, a young marginal rift basin located in the Gulf of California, are covered with thick sediment layers that are hydrothermally altered due to magmatic intrusions. To explore environmental controls on microbial community structure in this complex environment, we analyzed site- and depth-related patterns of microbial community composition (bacteria, archaea, and fungi) in hydrothermally influenced sediments with different thermal conditions, geochemical regimes, and extent of microbial mats. We compared communities in hot hydrothermal sediments (75-100°C at ~40 cm depth) covered by orange-pigmented Beggiatoaceae mats in the Cathedral Hill area, temperate sediments (25-30°C at ~40 cm depth) covered by yellow sulfur precipitates and filamentous sulfur oxidizers at the Aceto Balsamico location, hot sediments (>115°C at ~40 cm depth) with orange-pigmented mats surrounded by yellow and white mats at the Marker 14 location, and background, non-hydrothermal sediments (3.8°C at ~45 cm depth) overlain with ambient seawater. Whereas bacterial and archaeal communities are clearly structured by site-specific in-situ thermal gradients and geochemical conditions, fungal communities are generally structured by sediment depth. Unexpectedly, chytrid sequence biosignatures are ubiquitous in surficial sediments whereas deeper sediments contain diverse yeasts and filamentous fungi. In correlation analyses across different sites and sediment depths, fungal phylotypes correlate to each other to a much greater degree than Bacteria and Archaea do to each other or to fungi, further substantiating that site-specific in-situ thermal gradients and geochemical conditions that control bacteria and archaea do not extend to fungi.
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Affiliation(s)
- Gustavo A. Ramírez
- Department of Marine Sciences, University of North Carolina at Chapel Hill, NC, United States of America
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA, United States of America
- * E-mail:
| | - Paraskevi Mara
- Geology and Geophysics Dept., Woods Hole Oceanographic Institution, Woods Hole, MA, United States of America
| | - Taylor Sehein
- Geology and Geophysics Dept., Woods Hole Oceanographic Institution, Woods Hole, MA, United States of America
| | - Gunter Wegener
- MARUM, Center for Marine Environmental Sciences, University Bremen, Germany
- Max-Planck-Institute for Marine Microbiology, Bremen, Germany
| | - Christopher R. Chambers
- Department of Marine Sciences, University of North Carolina at Chapel Hill, NC, United States of America
| | - Samantha B. Joye
- Department of Marine Sciences, University of Georgia, Athens, GA, United States of America
| | - Richard N. Peterson
- School of Coastal and Marine Systems Science, Coastal Carolina University, Conway, SC, United States of America
| | - Aurélie Philippe
- Univ. Brest, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, Plouzané, France
| | - Gaëtan Burgaud
- Univ. Brest, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, Plouzané, France
| | - Virginia P. Edgcomb
- Geology and Geophysics Dept., Woods Hole Oceanographic Institution, Woods Hole, MA, United States of America
| | - Andreas P. Teske
- Department of Marine Sciences, University of North Carolina at Chapel Hill, NC, United States of America
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7
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Laundon D, Cunliffe M. A Call for a Better Understanding of Aquatic Chytrid Biology. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:708813. [PMID: 37744140 PMCID: PMC10512372 DOI: 10.3389/ffunb.2021.708813] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/09/2021] [Indexed: 09/26/2023]
Abstract
The phylum Chytridiomycota (the "chytrids") is an early-diverging, mostly unicellular, lineage of fungi that consists of significant aquatic saprotrophs, parasites, and pathogens, and is of evolutionary interest because its members retain biological traits considered ancestral in the fungal kingdom. While the existence of aquatic chytrids has long been known, their fundamental biology has received relatively little attention. We are beginning to establish a detailed understanding of aquatic chytrid diversity and insights into their ecological functions and prominence. However, the underpinning biology governing their aquatic ecological activities and associated core processes remain largely understudied and therefore unresolved. Many biological questions are outstanding for aquatic chytrids. What are the mechanisms that control their development and life cycle? Which core processes underpin their aquatic influence? What can their biology tell us about the evolution of fungi and the wider eukaryotic tree of life? We propose that the field of aquatic chytrid ecology could be further advanced through the improved understanding of chytrid biology, including the development of model aquatic chytrids and targeted studies using culture-independent approaches.
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Affiliation(s)
- Davis Laundon
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, United Kingdom
- School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
| | - Michael Cunliffe
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, United Kingdom
- School of Biological and Marine Sciences, University of Plymouth, Plymouth, United Kingdom
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8
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Klawonn I, Van den Wyngaert S, Parada AE, Arandia-Gorostidi N, Whitehouse MJ, Grossart HP, Dekas AE. Characterizing the "fungal shunt": Parasitic fungi on diatoms affect carbon flow and bacterial communities in aquatic microbial food webs. Proc Natl Acad Sci U S A 2021; 118:e2102225118. [PMID: 34074785 PMCID: PMC8201943 DOI: 10.1073/pnas.2102225118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Microbial interactions in aquatic environments profoundly affect global biogeochemical cycles, but the role of microparasites has been largely overlooked. Using a model pathosystem, we studied hitherto cryptic interactions between microparasitic fungi (chytrid Rhizophydiales), their diatom host Asterionella, and cell-associated and free-living bacteria. We analyzed the effect of fungal infections on microbial abundances, bacterial taxonomy, cell-to-cell carbon transfer, and cell-specific nitrate-based growth using microscopy (e.g., fluorescence in situ hybridization), 16S rRNA gene amplicon sequencing, and secondary ion mass spectrometry. Bacterial abundances were 2 to 4 times higher on individual fungal-infected diatoms compared to healthy diatoms, particularly involving Burkholderiales. Furthermore, taxonomic compositions of both diatom-associated and free-living bacteria were significantly different between noninfected and fungal-infected cocultures. The fungal microparasite, including diatom-associated sporangia and free-swimming zoospores, derived ∼100% of their carbon content from the diatom. By comparison, transfer efficiencies of photosynthetic carbon were lower to diatom-associated bacteria (67 to 98%), with a high cell-to-cell variability, and even lower to free-living bacteria (32%). Likewise, nitrate-based growth for the diatom and fungi was synchronized and faster than for diatom-associated and free-living bacteria. In a natural lacustrine system, where infection prevalence reached 54%, we calculated that 20% of the total diatom-derived photosynthetic carbon was shunted to the parasitic fungi, which can be grazed by zooplankton, thereby accelerating carbon transfer to higher trophic levels and bypassing the microbial loop. The herein termed "fungal shunt" can thus significantly modify the fate of photosynthetic carbon and the nature of phytoplankton-bacteria interactions, with implications for diverse pelagic food webs and global biogeochemical cycles.
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Affiliation(s)
- Isabell Klawonn
- Department of Earth System Science, Stanford University, Stanford, CA 94305;
| | - Silke Van den Wyngaert
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 12587 Berlin, Germany
| | - Alma E Parada
- Department of Earth System Science, Stanford University, Stanford, CA 94305
| | | | - Martin J Whitehouse
- Department of Geosciences, Swedish Museum of Natural History, 104 05 Stockholm, Sweden
| | - Hans-Peter Grossart
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 12587 Berlin, Germany
- Institute of Biochemistry and Biology, Potsdam University, 14476 Potsdam, Germany
| | - Anne E Dekas
- Department of Earth System Science, Stanford University, Stanford, CA 94305;
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