1
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Archibald KM, Dutkiewicz S, Laufkötter C, Moeller HV. Emergent trade-offs among plasticity strategies in mixotrophs. J Theor Biol 2024; 590:111854. [PMID: 38763324 DOI: 10.1016/j.jtbi.2024.111854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 03/14/2024] [Accepted: 05/14/2024] [Indexed: 05/21/2024]
Abstract
Marine mixotrophs combine phagotrophy and phototrophy to acquire the resources they need for growth. Metabolic plasticity, the ability for individuals to dynamically alter their relative investment between different metabolic processes, allows mixotrophs to efficiently exploit variable environmental conditions. Different mixotrophs may vary in how quickly they respond to environmental stimuli, with slow-responding mixotrophs exhibiting a significant lag between a change in the environment and the resulting change metabolic strategy. In this study, we develop a model of mixotroph metabolic strategy and explore how the rate of the plastic response affects the seasonality, competitive fitness, and biogeochemical role of mixotroph populations. Fast-responding mixotrophs are characterized by more efficient resource use and higher average growth rates than slow-responding mixotrophs because any lag in the plastic response following a change in environmental conditions creates a mismatch between the mixotroph's metabolic requirements and their resource acquisition. However, this mismatch also results in increased storage of unused resources that support growth under future nutrient-limited conditions. As a result of this trade-off, mixotroph biomass and productivity are maximized at intermediate plastic response rates. Furthermore, the trade-off represents a mechanism for coexistence between fast-responding and slow-responding mixotrophs. In mixed communities, fast-responding mixotrophs are numerically dominant, but slow-responding mixotrophs persist at low abundance due to the provisioning effect that emerges as a result of their less efficient resource acquisition strategy. In addition to increased competitive ability, fast-responding mixotrophs are, on average, more autotrophic than slow-responding mixotrophs. Notably, these trade-offs associated with mixotroph response rate arise without including an explicit physiological cost associated with plasticity, a conclusion that may provide insight into evolutionary constraints of metabolic plasticity in mixotrophic organisms. When an explicit cost is added to the model, it alters the competitive relationships between fast- and slow-responding mixotrophs. Faster plastic response rates are favored by lower physiological costs as well as higher amplitude seasonal cycles.
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Affiliation(s)
- Kevin M Archibald
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA.
| | - Stephanie Dutkiewicz
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA; Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Charlotte Laufkötter
- Climate and Environmental Physics, University of Bern, Bern, Switzerland; Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Holly V Moeller
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA
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2
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Miyagishima SY. Taming the perils of photosynthesis by eukaryotes: constraints on endosymbiotic evolution in aquatic ecosystems. Commun Biol 2023; 6:1150. [PMID: 37952050 PMCID: PMC10640588 DOI: 10.1038/s42003-023-05544-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 11/03/2023] [Indexed: 11/14/2023] Open
Abstract
An ancestral eukaryote acquired photosynthesis by genetically integrating a cyanobacterial endosymbiont as the chloroplast. The chloroplast was then further integrated into many other eukaryotic lineages through secondary endosymbiotic events of unicellular eukaryotic algae. While photosynthesis enables autotrophy, it also generates reactive oxygen species that can cause oxidative stress. To mitigate the stress, photosynthetic eukaryotes employ various mechanisms, including regulating chloroplast light absorption and repairing or removing damaged chloroplasts by sensing light and photosynthetic status. Recent studies have shown that, besides algae and plants with innate chloroplasts, several lineages of numerous unicellular eukaryotes engage in acquired phototrophy by hosting algal endosymbionts or by transiently utilizing chloroplasts sequestrated from algal prey in aquatic ecosystems. In addition, it has become evident that unicellular organisms engaged in acquired phototrophy, as well as those that feed on algae, have also developed mechanisms to cope with photosynthetic oxidative stress. These mechanisms are limited but similar to those employed by algae and plants. Thus, there appear to be constraints on the evolution of those mechanisms, which likely began by incorporating photosynthetic cells before the establishment of chloroplasts by extending preexisting mechanisms to cope with oxidative stress originating from mitochondrial respiration and acquiring new mechanisms.
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Affiliation(s)
- Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan.
- The Graduate University for Advanced Studies, SOKENDAI, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan.
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3
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Millette NC, Gast RJ, Luo JY, Moeller HV, Stamieszkin K, Andersen KH, Brownlee EF, Cohen NR, Duhamel S, Dutkiewicz S, Glibert PM, Johnson MD, Leles SG, Maloney AE, Mcmanus GB, Poulton N, Princiotta SD, Sanders RW, Wilken S. Mixoplankton and mixotrophy: future research priorities. JOURNAL OF PLANKTON RESEARCH 2023; 45:576-596. [PMID: 37483910 PMCID: PMC10361813 DOI: 10.1093/plankt/fbad020] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 04/14/2023] [Indexed: 07/25/2023]
Abstract
Phago-mixotrophy, the combination of photoautotrophy and phagotrophy in mixoplankton, organisms that can combine both trophic strategies, have gained increasing attention over the past decade. It is now recognized that a substantial number of protistan plankton species engage in phago-mixotrophy to obtain nutrients for growth and reproduction under a range of environmental conditions. Unfortunately, our current understanding of mixoplankton in aquatic systems significantly lags behind our understanding of zooplankton and phytoplankton, limiting our ability to fully comprehend the role of mixoplankton (and phago-mixotrophy) in the plankton food web and biogeochemical cycling. Here, we put forward five research directions that we believe will lead to major advancement in the field: (i) evolution: understanding mixotrophy in the context of the evolutionary transition from phagotrophy to photoautotrophy; (ii) traits and trade-offs: identifying the key traits and trade-offs constraining mixotrophic metabolisms; (iii) biogeography: large-scale patterns of mixoplankton distribution; (iv) biogeochemistry and trophic transfer: understanding mixoplankton as conduits of nutrients and energy; and (v) in situ methods: improving the identification of in situ mixoplankton and their phago-mixotrophic activity.
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Affiliation(s)
| | - Rebecca J Gast
- Woods Hole Oceanographic Institution, 266 Woods Hole Rd, Woods Hole, MA 02543, USA
| | - Jessica Y Luo
- NOAA Geophysical Fluid Dynamics Laboratory, 201 Forrestal Rd., Princeton, NJ 08540, USA
| | - Holly V Moeller
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, 1120 Noble Hall, Santa Barbara, CA 93106, USA
| | - Karen Stamieszkin
- Bigelow Laboratory for Ocean Sciences, 60 Bigelow Dr., East Boothbay, ME 04544, USA
| | - Ken H Andersen
- Center for Ocean Life, Natl. Inst. of Aquatic Resources, Technical University of Denmark, Kemitorvet, Bygning 202, Kongens Lyngby 2840, Denmark
| | - Emily F Brownlee
- Department of Biology, St. Mary’s College of Maryland, 18952 E. Fisher Road, St. Mary’s City, MD 20686, USA
| | - Natalie R Cohen
- Skidaway Institute of Oceanography, University of Georgia, 10 Ocean Science Circle, Savannah, GA 31411, USA
| | - Solange Duhamel
- Department of Molecular and Cellular Biology, The University of Arizona, 1007 E Lowell Street, Tucson, AZ 85721, USA
| | - Stephanie Dutkiewicz
- Center for Global Change Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02874, USA
| | - Patricia M Glibert
- Horn Point Laboratory, University of Maryland Center for Environmental Science, 2020 Horns Point Rd, Cambridge, MD 21613, USA
| | - Matthew D Johnson
- Woods Hole Oceanographic Institution, 266 Woods Hole Rd, Woods Hole, MA 02543, USA
| | - Suzana G Leles
- Department of Marine and Environmental Biology, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA 90089, USA
| | - Ashley E Maloney
- Geosciences Department, Princeton University, Guyot Hall, Princeton, NJ 08544, USA
| | - George B Mcmanus
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Rd., Groton, CT 06340, USA
| | - Nicole Poulton
- Bigelow Laboratory for Ocean Sciences, 60 Bigelow Dr., East Boothbay, ME 04544, USA
| | - Sarah D Princiotta
- Biology Department, Pennsylvania State University, Schuylkill Campus, 200 University Drive, Schuylkill Haven, PA 17972, USA
| | - Robert W Sanders
- Department of Biology, Temple University, 1900 N. 12th St., Philadelphia, PA 19122, USA
| | - Susanne Wilken
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, The Netherlands
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4
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Maselli M, Meire L, Meire P, Hansen PJ. Effects of Glacial Flour on Marine Micro-plankton: Evidences from Natural Communities of Greenlandic Fjords and Experimental Studies. Protist 2023; 174:125928. [PMID: 36442289 DOI: 10.1016/j.protis.2022.125928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
Abstract
Meltwater runoff from glaciers carries particles, so-called glacial flour that may affect planktonic organisms and the functioning of marine ecosystems. Protist microplankton is at the base of marine food webs and thus plays an important role in sustaining important ecosystem services. To assess the effect of glacial flour on photoautotrophic, heterotrophic and mixotrophic microplankton, the spatial distribution of these trophic groups was studied in four Greenlandic fjords during summer. The results suggest that the abundance of the autotrophic microplankton was affected by the glacier meltwater due to reduced light penetration and nutrient availability. The abundance of heterotrophic and mixotrophic microplankton were not apparently affected by the glacier meltwater. Incubation experiments were conducted on the natural population and in laboratory cultures of two mixoplanktonic ciliate species. The experiments on the natural population revealed that none of the trophic groups were affected by the suspended material at concentrations up to 50 mg L-1. The experiments on cultures gave no indication that glacial flour was ingested by the mixoplanktonic ciliates. Growth rates of cultured ciliates were not affected by the glacial flour addition. These results suggest that heterotrophic and mixotrophic microplankton are not affected by glacial flour as much as autotrophic microplankton.
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Affiliation(s)
- Maira Maselli
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.
| | - Lorenz Meire
- Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research, Yerseke, The Netherlands; Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland
| | - Patrick Meire
- Ecosystem Management Research Group, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium
| | - Per Juel Hansen
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
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5
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Edwards KF, Li Q, McBeain KA, Schvarcz CR, Steward GF. Trophic strategies explain the ocean niches of small eukaryotic phytoplankton. Proc Biol Sci 2023; 290:20222021. [PMID: 36695036 PMCID: PMC9874276 DOI: 10.1098/rspb.2022.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A large fraction of marine primary production is performed by diverse small protists, and many of these phytoplankton are phagotrophic mixotrophs that vary widely in their capacity to consume bacterial prey. Prior analyses suggest that mixotrophic protists as a group vary in importance across ocean environments, but the mechanisms leading to broad functional diversity among mixotrophs, and the biogeochemical consequences of this, are less clear. Here we use isolates from seven major taxa to demonstrate a tradeoff between phototrophic performance (growth in the absence of prey) and phagotrophic performance (clearance rate when consuming Prochlorococcus). We then show that trophic strategy along the autotrophy-mixotrophy spectrum correlates strongly with global niche differences, across depths and across gradients of stratification and chlorophyll a. A model of competition shows that community shifts can be explained by greater fitness of faster-grazing mixotrophs when nutrients are scarce and light is plentiful. Our results illustrate how basic physiological constraints and principles of resource competition can organize complexity in the surface ocean ecosystem.
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Affiliation(s)
- Kyle F. Edwards
- Department of Oceanography, School of Ocean and Earth Science and Technology (SOEST), University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA
| | - Qian Li
- Department of Oceanography, School of Ocean and Earth Science and Technology (SOEST), University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA,Daniel K. Inouye Center for Microbial Oceanography: Research and Education, School of Ocean and Earth Science and Technology (SOEST), University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA,School of Oceanography, Shanghai Jiao Tong University, 1954 Huashan Rd, Shanghai Shi, Xuhui Qu 200240, China
| | - Kelsey A. McBeain
- Department of Oceanography, School of Ocean and Earth Science and Technology (SOEST), University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA
| | - Christopher R. Schvarcz
- Department of Oceanography, School of Ocean and Earth Science and Technology (SOEST), University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA,Daniel K. Inouye Center for Microbial Oceanography: Research and Education, School of Ocean and Earth Science and Technology (SOEST), University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA
| | - Grieg F. Steward
- Department of Oceanography, School of Ocean and Earth Science and Technology (SOEST), University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA,Daniel K. Inouye Center for Microbial Oceanography: Research and Education, School of Ocean and Earth Science and Technology (SOEST), University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA
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6
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Grattepanche JD, Jeffrey WH, Gast RJ, Sanders RW. Diversity of Microbial Eukaryotes Along the West Antarctic Peninsula in Austral Spring. Front Microbiol 2022; 13:844856. [PMID: 35651490 PMCID: PMC9149413 DOI: 10.3389/fmicb.2022.844856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 03/17/2022] [Indexed: 11/13/2022] Open
Abstract
During a cruise from October to November 2019, along the West Antarctic Peninsula, between 64.32 and 68.37°S, we assessed the diversity and composition of the active microbial eukaryotic community within three size fractions: micro- (> 20 μm), nano- (20-5 μm), and pico-size fractions (5-0.2 μm). The communities and the environmental parameters displayed latitudinal gradients, and we observed a strong similarity in the microbial eukaryotic communities as well as the environmental parameters between the sub-surface and the deep chlorophyll maximum (DCM) depths. Chlorophyll concentrations were low, and the mixed layer was shallow for most of the 17 stations sampled. The richness of the microplankton was higher in Marguerite Bay (our southernmost stations), compared to more northern stations, while the diversity for the nano- and pico-plankton was relatively stable across latitude. The microplankton communities were dominated by autotrophs, mostly diatoms, while mixotrophs (phototrophs-consuming bacteria and kleptoplastidic ciliates, mostly alveolates, and cryptophytes) were the most abundant and active members of the nano- and picoplankton communities. While phototrophy was the dominant trophic mode, heterotrophy (mixotrophy, phagotrophy, and parasitism) tended to increase southward. The samples from Marguerite Bay showed a distinct community with a high diversity of nanoplankton predators, including spirotrich ciliates, and dinoflagellates, while cryptophytes were observed elsewhere. Some lineages were significantly related-either positively or negatively-to ice coverage (e.g., positive for Pelagophyceae, negative for Spirotrichea) and temperature (e.g., positive for Cryptophyceae, negative for Spirotrichea). This suggests that climate changes will have a strong impact on the microbial eukaryotic community.
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Affiliation(s)
| | - Wade H. Jeffrey
- Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, FL, United States
| | - Rebecca J. Gast
- Department of Biology, Woods Hole Oceanographic Institution, Pensacola, MA, United States
| | - Robert W. Sanders
- Department of Biology, Temple University, Philadelphia, PA, United States
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7
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Cormier M, Berard J, Bougaran G, Trueman CN, Mayor DJ, Lampitt RS, Kruger NJ, Flynn KJ, Rickaby REM. Deuterium in marine organic biomarkers: toward a new tool for quantifying aquatic mixotrophy. THE NEW PHYTOLOGIST 2022; 234:776-782. [PMID: 35133656 PMCID: PMC9310953 DOI: 10.1111/nph.18023] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
The traditional separation between primary producers (autotrophs) and consumers (heterotrophs) at the base of the marine food web is being increasingly replaced by the paradigm that mixoplankton, planktonic protists with the nutritional ability to use both phago(hetero)trophy and photo(auto)trophy to access energy are widespread globally. Thus, many 'phytoplankton' eat, while 50% of 'protozooplankton' also perform photosynthesis. Mixotrophy may enhance primary production, biomass transfer to higher trophic levels and the efficiency of the biological pump to sequester atmospheric CO2 into the deep ocean. Although this view is gaining traction, science lacks a tool to quantify the relative contributions of autotrophy and heterotrophy in planktonic protists. This hinders our understanding of their impacts on carbon cycling within marine pelagic ecosystems. It has been shown that the hydrogen (H) isotopic signature of lipids is uniquely sensitive to heterotrophy relative to autotrophy in plants and bacteria. Here, we explored whether it is also sensitive to the trophic status in protists. The new understanding of H isotope signature of lipid biomarkers suggests it offers great potential as a novel tool for quantifying the prevalence of mixotrophy in diverse marine microorganisms and thus for investigating the implications of the 'mixoplankton' paradigm.
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Affiliation(s)
- Marc‐André Cormier
- Department of Earth SciencesUniversity of OxfordSouth Parks RoadOxfordOX1 3ANUK
| | - Jean‐Baptiste Berard
- IFREMER, Physiology and Biotechnology of Algae (PBA) Laboratoryrue de l'Ile d'Yeu, BP 21105Nantes Cedex 344311France
| | - Gaël Bougaran
- IFREMER, Physiology and Biotechnology of Algae (PBA) Laboratoryrue de l'Ile d'Yeu, BP 21105Nantes Cedex 344311France
| | - Clive N. Trueman
- Ocean and Earth ScienceNational Oceanography Centre SouthamptonUniversity of SouthamptonSouthamptonSO14 3ZHUK
| | - Daniel J. Mayor
- Ocean BiogeosciencesNational Oceanography CentreSouthamptonSO14 3ZHUK
| | | | - Nicholas J. Kruger
- Department of Plant SciencesUniversity of OxfordSouth Parks RoadOxfordOX1 3RBUK
| | - Kevin J. Flynn
- Plymouth Marine LaboratoryProspect PlacePlymouthPL1 3DHUK
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8
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Hsu V, Pfab F, Moeller HV. Niche expansion via acquired metabolism facilitates competitive dominance in planktonic communities. Ecology 2022; 103:e3693. [PMID: 35349727 DOI: 10.1002/ecy.3693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 12/17/2021] [Accepted: 01/18/2022] [Indexed: 11/07/2022]
Abstract
Acquired phototrophs, organisms that obtain their photosynthetic abilities by hosting endosymbionts or stealing plastids from their prey, are omnipresent in aquatic ecosystems. This acquisition of photosynthetic metabolism allows for niche expansion, and can therefore influence competition outcomes by alleviating competition for shared resources. Here, we test how acquired metabolism alters competitive outcomes by manipulating light availability to control the energetic contribution of photosynthesis to acquired phototrophs. Using freshwater protists that compete for bacterial prey, we demonstrate light-dependent competition outcomes of acquired phototrophs (Paramecium bursaria) and strict heterotrophs (Colpidium sp.) in laboratory model experiments. We then synthesize these findings using a series of mathematical models, and show that explicitly accounting for resource competition improves model fits. Both empirical and mathematical models predict that the acquired phototroph should increase in competitive dominance with increasing light availability. Our results highlight the importance of acquired metabolism to community dynamics, highlighting the need for more empirical and theoretical studies of this mechanism for niche expansion.
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Affiliation(s)
- Veronica Hsu
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, USA
| | - Ferdinand Pfab
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, USA
| | - Holly V Moeller
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, California, USA
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9
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The dynamic trophic architecture of open-ocean protist communities revealed through machine-guided metatranscriptomics. Proc Natl Acad Sci U S A 2022; 119:2100916119. [PMID: 35145022 PMCID: PMC8851463 DOI: 10.1073/pnas.2100916119] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2021] [Indexed: 12/25/2022] Open
Abstract
Mixotrophy is a ubiquitous nutritional strategy in marine ecosystems. Although our understanding of the distribution and abundance of mixotrophic plankton has improved significantly, the functional roles of mixotrophs are difficult to pinpoint, as mixotroph nutritional strategies are flexible and form a continuum between heterotrophy and phototrophy. We developed a machine learning–based method to assess the nutritional strategies of in situ planktonic populations based on metatranscriptomic profiles. We demonstrate that mixotrophic populations play varying functional roles along physicochemical gradients in the North Pacific Ocean, revealing a degree of physiological plasticity unique to aquatic mixotrophs. Our results highlight mechanisms that may dictate the flow of biogeochemical elements and ecology of the North Pacific Ocean, one of Earth's largest biogeographical provinces. Intricate networks of single-celled eukaryotes (protists) dominate carbon flow in the ocean. Their growth, demise, and interactions with other microorganisms drive the fluxes of biogeochemical elements through marine ecosystems. Mixotrophic protists are capable of both photosynthesis and ingestion of prey and are dominant components of open-ocean planktonic communities. Yet the role of mixotrophs in elemental cycling is obscured by their capacity to act as primary producers or heterotrophic consumers depending on factors that remain largely uncharacterized. Here, we develop and apply a machine learning model that predicts the in situ trophic mode of aquatic protists based on their patterns of gene expression. This approach leverages a public collection of protist transcriptomes as a training set to identify a subset of gene families whose transcriptional profiles predict trophic mode. We applied our model to nearly 100 metatranscriptomes obtained during two oceanographic cruises in the North Pacific and found community-level and population-specific evidence that abundant open-ocean mixotrophic populations shift their predominant mode of nutrient and carbon acquisition in response to natural gradients in nutrient supply and sea surface temperature. Metatranscriptomic data from ship-board incubation experiments revealed that abundant mixotrophic prymnesiophytes from the oligotrophic North Pacific subtropical gyre rapidly remodeled their transcriptome to enhance photosynthesis when supplied with limiting nutrients. Coupling this approach with experiments designed to reveal the mechanisms driving mixotroph physiology provides an avenue toward understanding the ecology of mixotrophy in the natural environment.
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10
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Duarte Ferreira G, Romano F, Medić N, Pitta P, Hansen PJ, Flynn KJ, Mitra A, Calbet A. Mixoplankton interferences in dilution grazing experiments. Sci Rep 2021; 11:23849. [PMID: 34903787 PMCID: PMC8668877 DOI: 10.1038/s41598-021-03176-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 11/29/2021] [Indexed: 11/09/2022] Open
Abstract
It remains unclear as to how mixoplankton (coupled phototrophy and phagotrophy in one cell) affects the estimation of grazing rates obtained from the widely used dilution grazing technique. To address this issue, we prepared laboratory-controlled dilution experiments with known mixtures of phyto-, protozoo-, and mixoplankton, operated under different light regimes and species combinations. Our results evidenced that chlorophyll is an inadequate proxy for phytoplankton when mixoplankton are present. Conversely, species-specific cellular counts could assist (although not fully solve) in the integration of mixoplanktonic activity in a dilution experiment. Moreover, cell counts can expose prey selectivity patterns and intraguild interactions among grazers. Our results also demonstrated that whole community approaches mimic reality better than single-species laboratory experiments. We also confirmed that light is required for protozoo- and mixoplankton to correctly express their feeding activity, and that overall diurnal grazing is higher than nocturnal. Thus, we recommend that a detailed examination of initial and final plankton communities should become routine in dilution experiments, and that incubations should preferably be started at the beginning of both day and night periods. Finally, we hypothesize that in silico approaches may help disentangle the contribution of mixoplankton to the community grazing of a given system.
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Affiliation(s)
- Guilherme Duarte Ferreira
- Institut de Ciències del Mar, CSIC, Pg. Marítim de la Barceloneta, 37-49, 08003, Barcelona, Spain. .,Marine Biological Section, University of Copenhagen, 3000, Helsingør, Denmark.
| | - Filomena Romano
- Marine Biological Section, University of Copenhagen, 3000, Helsingør, Denmark.,Institute of Oceanography, Hellenic Centre for Marine Research, PO Box 2214, 71003, Heraklion, Greece
| | - Nikola Medić
- Marine Biological Section, University of Copenhagen, 3000, Helsingør, Denmark
| | - Paraskevi Pitta
- Institute of Oceanography, Hellenic Centre for Marine Research, PO Box 2214, 71003, Heraklion, Greece
| | - Per Juel Hansen
- Marine Biological Section, University of Copenhagen, 3000, Helsingør, Denmark
| | - Kevin J Flynn
- Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, UK
| | - Aditee Mitra
- School of Earth and Environmental Sciences, Cardiff University, Park Place, Cardiff, CF10 3AT, UK
| | - Albert Calbet
- Institut de Ciències del Mar, CSIC, Pg. Marítim de la Barceloneta, 37-49, 08003, Barcelona, Spain
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11
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Modeling mixoplankton along the biogeochemical gradient of the Southern North Sea. Ecol Modell 2021; 459:109690. [PMID: 34732971 PMCID: PMC8507435 DOI: 10.1016/j.ecolmodel.2021.109690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 07/27/2021] [Accepted: 07/29/2021] [Indexed: 11/22/2022]
Abstract
The ecological importance of mixoplankton within marine protist communities is slowly being recognized. However, most aquatic ecosystem models do not include formulations to model a complete protist community consisting of phytoplankton, protozooplankton and mixoplankton. We introduce PROTIST, a new module for the aquatic ecosystem modelling software Delft3D-WAQ that can model a protist community consisting of two types of phytoplankton (diatoms and green algae), two types of mixoplankton (constitutive mixoplankton and non-constitutive mixoplankton) and protozooplankton. We employed PROTIST to further explore the hypothesis that the biogeochemical gradient of inorganic nutrient and suspended sediment concentrations drives the observed occurrence of constitutive mixoplankton in the Dutch Southern North Sea. To explore this hypothesis, we used 11 1D-vertical aquatic ecosystem models that mimic the abiotic conditions of 11 routine monitoring locations in the Dutch Southern North Sea. Our models result in plausible trophic compositions across the biogeochemical gradient as compared to in-situ data. A sensitivity analysis showed that the dissolved inorganic phosphate and silica concentrations drive the occurrence of constitutive mixoplankton in the Dutch Southern North Sea. A model to simulate the protist community including mixoplankton is introduced. The model was tested in 1D-V models along a biogeochemical gradient. Modelled mixoplankton are more sensitive to nutrients than to light.
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12
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Hughes EA, Maselli M, Sørensen H, Hansen PJ. Metabolic Reliance on Photosynthesis Depends on Both Irradiance and Prey Availability in the Mixotrophic Ciliate, Strombidium cf. basimorphum. Front Microbiol 2021; 12:642600. [PMID: 34220736 PMCID: PMC8245785 DOI: 10.3389/fmicb.2021.642600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 05/24/2021] [Indexed: 11/17/2022] Open
Abstract
Many species of the ciliate genus Strombidium can acquire functional chloroplasts from a wide range of algal prey and are thus classified as generalist non-constitutive mixotrophs. Little, however, is known about the influence of irradiance and prey availability on their ability to exploit the photosynthetic potential of the chloroplasts, and how this may explain their spatial and temporal distribution in nature. In this study, inorganic carbon uptake, growth, and ingestion rates were measured for S. cf. basimorphum under three different irradiances (10, 40, and 120 μmol photons m–2 s–1) when acclimated to three different prey densities (5 × 103, 1 × 104, and 4 × 104 cells mL–1), as well as when allowed to deplete the prey. After prey depletion, cultures survived without prey longest (∼6 days) at the medium irradiance treatment (40 μmol photons m–2 s–1), while ciliate density, inorganic carbon uptake rates, and cellular chl-a content declined fastest at the highest irradiance treatment. This indicates that the ciliates may be unable to maintain the chloroplasts functionally without replacement at high irradiances. Ingestion rates were not shown to be significantly influenced by irradiance. The maximum gross growth efficiency (GGE) in this study (1.1) was measured in cultures exposed to the medium test irradiance and lowest prey density treatment (5 × 103 cells mL–1). The relative contribution of inorganic carbon uptake to the ciliate carbon budget was also highest in this treatment (42%). A secondary GGE peak (0.99) occurred when cultures were exposed to the highest test irradiance and the medium prey density. These and other results suggest that S. cf. basimorphum, and other generalist non-constitutive mixotrophs, can flexibly exploit many different environmental conditions across the globe.
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Affiliation(s)
- Erin Ann Hughes
- Marine Biological Section, Biological Institute, University of Copenhagen, Copenhagen, Denmark
| | - Maira Maselli
- Marine Biological Section, Biological Institute, University of Copenhagen, Copenhagen, Denmark
| | - Helle Sørensen
- Data Science Lab, Department of Mathematical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Per Juel Hansen
- Marine Biological Section, Biological Institute, University of Copenhagen, Copenhagen, Denmark
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Zhang S, Xia X, Ke Y, Song S, Shen Z, Cheung S, Liu H. Population dynamics and interactions of Noctiluca scintillans and Mesodinium rubrum during their successive blooms in a subtropical coastal water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142349. [PMID: 33032128 DOI: 10.1016/j.scitotenv.2020.142349] [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: 05/21/2020] [Revised: 09/09/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
A time series field survey were conducted in Port Shelter, a subtropical coastal water in NW Pacific, beginning before the onset of a chain of Noctiluca scintillans and/or Mesodinium rubrum blooms, and ending after the blooms had declined. At the first mixed bloom stage, seed of N. scintillans and the consequent outbreak of both N. scintillans and M. rubrum were largely due to the physical forcing. Plenty food supply and their different feeding habits supported N. scintillans and M. rubrum to bloom massively and concomitantly. Following that, there was a small N. scintillans bloom followed by a small crest of M. rubrum. Their initiation and scale were mainly affected by limited food supply and/or the inferior food source. Sudden change of wind from mild northeast wind to strong southeast wind might contribute to the termination of N. scintillans bloom. Finally, physical accumulation was the most important driving factors of the formation and dispersal of the third and largest bloom of N. scintillans. Formation of these bloom events may involve vertical migration and/or the concentrating mechanism of M. rubrum and N. scintillans. Meanwhile, biotic interactions such as mutual supportive relationship between N. scintillans and M. rubrum, and O. hongkongense fed on the progametes of N. scintillans, as well as other abiotic factors like seawater temperature and rainfall, also play important roles in this series of bloom events. Our findings have important implications for coastal zones worldwide, which are affected recurrently by these two ubiquitous red tide-forming species.
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Affiliation(s)
- Shuwen Zhang
- Guangdong Provincial Key Laboratory of Healthy and Safe Aquaculture, College of Life Science, South China Normal University, West 55 of Zhongshan Avenue, Guangzhou 510631, PR China
| | - Xiaomin Xia
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, PR China; Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, PR China
| | - Ying Ke
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region
| | - Shuqun Song
- Key Lab of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, PR China
| | - Zhuo Shen
- Institute of Microbial Ecology and Matter Cycle, School of Marine Sciences, Sun Yat-sen University, Zhuhai, PR China
| | - Shunyan Cheung
- Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region
| | - Hongbin Liu
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region; Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region.
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Plasticity and Multiplicity of Trophic Modes in the Dinoflagellate Karlodinium and Their Pertinence to Population Maintenance and Bloom Dynamics. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2021. [DOI: 10.3390/jmse9010051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
As the number of mixotrophic protists has been increasingly documented, “mixoplankton”, a third category separated from the traditional categorization of plankton into “phytoplankton” and “zooplankton”, has become a new paradigm and research hotspot in aquatic plankton ecology. While species of dinoflagellates are a dominant group among all recorded members of mixoplankton, the trophic modes of Karlodinium, a genus constituted of cosmopolitan toxic species, were reviewed due to their representative features as mixoplankton and harmful algal blooms (HABs)-causing dinoflagellates. Among at least 15 reported species in the genus, three have been intensively studied for their trophic modes, and all found to be phagotrophic. Their phagotrophy exhibits multiple characteristics: (1) omnivority, i.e., they can ingest a variety of preys in many forms; (2) flexibility in phagotrophic mechanisms, i.e., they can ingest small preys by direct engulfment and much bigger preys by myzocytosis using a peduncle; (3) cannibalism, i.e., species including at least K. veneficum can ingest the dead cells of their own species. However, for some recently described and barely studied species, their tropical modes still need to be investigated further regarding all of the above-mentioned aspects. Mixotrophy of Karlodinium plays a significant role in the population dynamics and the formation of HABs in many ways, which thus deserves further investigation in the aspects of physiological ecology, environmental triggers (e.g., levels of inorganic nutrients and/or presence of preys), energetics, molecular (genes and gene expression regulations) and biochemical (e.g., relevant enzymes and signal molecules) bases, origins, and evaluation of the advantages of being a phagotroph.
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15
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Schneider LK, Anestis K, Mansour J, Anschütz AA, Gypens N, Hansen PJ, John U, Klemm K, Martin JL, Medic N, Not F, Stolte W. A dataset on trophic modes of aquatic protists. Biodivers Data J 2020; 8:e56648. [PMID: 33177947 PMCID: PMC7599203 DOI: 10.3897/bdj.8.e56648] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/08/2020] [Indexed: 11/12/2022] Open
Abstract
Background An important functional trait of organisms is their trophic mode. It determines their position within food webs, as well as their function within an ecosystem. For the better part of the 20th century, aquatic protist communities were thought to consist mainly of producers (phytoplankton) and consumers (protozooplankton). Phytoplankton cover their energy requirements through photosynthesis (phototrophy), while protozooplankton graze on prey and organic particles (phagotrophy). However, over the past decades, it was shown that another trophic group (mixoplankton) comprise a notable part of aquatic protist communities. Mixoplankton employ a third trophic mode by combining phototrophy and phagotrophy (mixotrophy). Due to the historical dichotomy, it is not straightforward to gain adequate and correct information on the trophic mode of aquatic protists. Long hours of literature research or expert knowledge are needed to correctly assign trophic modes. Additionally, aquatic protists also have a long history of undergoing taxonomic changes which make it difficult to compare past and present literature. While WoRMS, the World Register of Marine Species, keeps track of the taxonomic changes and assigns each species a unique AphiaID that can be linked to its various historic and present taxonomic hierarchy, there is currently no machine-readable database to query aquatic protists for their trophic modes. New information This paper describes a dataset that was submitted to WoRMS and links aquatic protist taxa, with a focus on marine taxa, to their AphiaID and their trophic mode. The bulk of the data used for this dataset stems from (routine) monitoring stations in the North Sea and the Baltic Sea. The data were augmented and checked against state-of-the-art knowledge on mixoplankton taxa by consulting literature and experts. Thus, this dataset provides a first attempt to make the trophic mode of aquatic protists easily accessible in both a human- and machine-readable format.
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Affiliation(s)
- Lisa K Schneider
- Deltares, Delft, Netherlands Deltares Delft Netherlands.,Université Libre de Bruxelles, Bruxelles, Belgium Université Libre de Bruxelles Bruxelles Belgium
| | - Konstantinos Anestis
- Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research Bremerhaven Germany
| | - Joost Mansour
- Sorbonne University, CNRS, Roscoff, France Sorbonne University, CNRS Roscoff France
| | - Anna A Anschütz
- School of Earth and Ocean Sciences, Cardiff University, Cardiff, United Kingdom School of Earth and Ocean Sciences, Cardiff University Cardiff United Kingdom.,Université Libre de Bruxelles, Bruxelles, Belgium Université Libre de Bruxelles Bruxelles Belgium
| | - Nathalie Gypens
- Université Libre de Bruxelles, Bruxelles, Belgium Université Libre de Bruxelles Bruxelles Belgium
| | - Per J Hansen
- Marine Biological Laboratory, University of Copenhagen, Copenhagen, Denmark Marine Biological Laboratory, University of Copenhagen Copenhagen Denmark
| | - Uwe John
- Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research Bremerhaven Germany.,Helmholtz Institute for Functional Marine Biodiversity, Oldenburg, Germany Helmholtz Institute for Functional Marine Biodiversity Oldenburg Germany
| | - Kerstin Klemm
- Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research Bremerhaven Germany
| | - Jon Lapeya Martin
- Université Libre de Bruxelles, Bruxelles, Belgium Université Libre de Bruxelles Bruxelles Belgium
| | - Nikola Medic
- Marine Biological Laboratory, University of Copenhagen, Copenhagen, Denmark Marine Biological Laboratory, University of Copenhagen Copenhagen Denmark
| | | | - Willem Stolte
- Deltares, Delft, Netherlands Deltares Delft Netherlands
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Avrahami Y, Frada MJ. Detection of Phagotrophy in the Marine Phytoplankton Group of the Coccolithophores (Calcihaptophycidae, Haptophyta) During Nutrient-replete and Phosphate-limited Growth. JOURNAL OF PHYCOLOGY 2020; 56:1103-1108. [PMID: 32233088 DOI: 10.1111/jpy.12997] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 03/12/2020] [Indexed: 05/13/2023]
Abstract
Mixotrophic algae that combine photoautotrophy with phagotrophy in a single cell are prevalent in marine ecosystems. Here, we assessed the ability of food ingestion in coccolithophores, an important group of calcifying haptophytes inhabiting the oceans. We tested four species from different coccolithophore lineages (Emiliania huxleyi, Calcidiscus leptoporus, Coccolithus braarudii, and Calyptrosphaera sphaeroidea). For both E. huxleyi and C. leptoporus we included different life phases (haploid and diploid). For C. braarudii we only tested diploid heterococcolithophore cells, while for C. sphaeroidea we only tested haploid holococcolithophore cells. Phagotrophy was assessed using fluorescently labeled bacteria (FLB) as model prey item, under nutrient-replete and phosphate-limited conditions. We detected by microscopy ingestion of FLB by all species, except the diploid C. braarudii strain. However, a previous study detected ingestion by haploid cells of C. braarudii. These overall results indicate that mixotrophy and the ability to ingest prey is widespread in coccolithophores. Yet, in all tested species the ingestion of FLB was low (<1% of the population contained prey at all time points over 2 days), namely for E. huxleyi and the diploid cells from C. leptoporus where detection of ingestion was sporadic. Moreover, no clear differences were detected between life phases in E. huxleyi and C. leptoporus under equal circumstances, or between replete and limited growth conditions.
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Affiliation(s)
- Yoav Avrahami
- The Interuniversity Institute for Marine Sciences in Eilat, 88103, Eilat, Israel
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Miguel J Frada
- The Interuniversity Institute for Marine Sciences in Eilat, 88103, Eilat, Israel
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
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17
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Caveats on the use of rotenone to estimate mixotrophic grazing in the oceans. Sci Rep 2020; 10:3899. [PMID: 32127594 PMCID: PMC7054392 DOI: 10.1038/s41598-020-60764-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 02/13/2020] [Indexed: 11/25/2022] Open
Abstract
Phagotrophic mixotrophs (mixoplankton) are now widely recognised as important members of food webs, but their role in the functioning of food webs is not yet fully understood. This is due to the lack of a well-established technique to estimate mixotrophic grazing. An immediate step in this direction would be the development of a method that separates mixotrophic from heterotrophic grazing that can be routinely incorporated into the common techniques used to measure microplankton herbivory (e.g., the dilution technique). This idea was explored by the addition of rotenone, an inhibitor of the respiratory electron chain that has been widely used to selectively eliminate metazoans, both in the field and in the laboratory. Accordingly, rotenone was added to auto-, mixo-, and heterotrophic protist cultures in increasing concentrations (ca. 24 h). The results showed that mixotrophs survived better than heterotrophs at low concentrations of rotenone. Nevertheless, their predation was more affected, rendering rotenone unusable as a heterotrophic grazing deterrent. Additionally, it was found that rotenone had a differential effect depending on the growth phase of an autotrophic culture. Altogether, these results suggest that previous uses of rotenone in the field may have disrupted the planktonic food web.
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18
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Morard R, Füllberg A, Brummer GJA, Greco M, Jonkers L, Wizemann A, Weiner AKM, Darling K, Siccha M, Ledevin R, Kitazato H, de Garidel-Thoron T, de Vargas C, Kucera M. Genetic and morphological divergence in the warm-water planktonic foraminifera genus Globigerinoides. PLoS One 2019; 14:e0225246. [PMID: 31805130 PMCID: PMC6894840 DOI: 10.1371/journal.pone.0225246] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 10/31/2019] [Indexed: 11/19/2022] Open
Abstract
The planktonic foraminifera genus Globigerinoides provides a prime example of a species-rich genus in which genetic and morphological divergence are uncorrelated. To shed light on the evolutionary processes that lead to the present-day diversity of Globigerinoides, we investigated the genetic, ecological and morphological divergence of its constituent species. We assembled a global collection of single-cell barcode sequences and show that the genus consists of eight distinct genetic types organized in five extant morphospecies. Based on morphological evidence, we reassign the species Globoturborotalita tenella to Globigerinoides and amend Globigerinoides ruber by formally proposing two new subspecies, G. ruber albus n.subsp. and G. ruber ruber in order to express their subspecies level distinction and to replace the informal G. ruber "white" and G. ruber "pink", respectively. The genetic types within G. ruber and Globigerinoides elongatus show a combination of endemism and coexistence, with little evidence for ecological differentiation. CT-scanning and ontogeny analysis reveal that the diagnostic differences in adult morphologies could be explained by alterations of the ontogenetic trajectories towards final (reproductive) size. This indicates that heterochrony may have caused the observed decoupling between genetic and morphological diversification within the genus. We find little evidence for environmental forcing of either the genetic or the morphological diversification, which allude to biotic interactions such as symbiosis, as the driver of speciation in Globigerinoides.
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Affiliation(s)
- Raphaël Morard
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, Bremen, Germany
| | - Angelina Füllberg
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, Bremen, Germany
| | - Geert-Jan A. Brummer
- NIOZ Royal Netherlands Institute for Sea Research, Department of Ocean Systems, and Utrecht University, Den Burg, and Utrecht University, The Netherlands
- Vrije Universiteit Amsterdam, Department of Earth Sciences, Faculty of Science, Amsterdam, The Netherlands
| | - Mattia Greco
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, Bremen, Germany
| | - Lukas Jonkers
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, Bremen, Germany
| | - André Wizemann
- Leibniz Centre for Tropical Marine Research, Bremen, Germany
| | - Agnes K. M. Weiner
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, Bremen, Germany
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
| | - Kate Darling
- School of GeoSciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- School of Geography and Sustainable Development, University of St Andrews, St Andrews, Scotland, United Kingdom
| | - Michael Siccha
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, Bremen, Germany
| | - Ronan Ledevin
- UMR5199 PACEA, Université de Bordeaux, Allée Geoffroy Saint Hilaire, Pessac, France
| | - Hiroshi Kitazato
- Japan Agency for Marine Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan
| | | | - Colomban de Vargas
- Sorbonne Université, CNRS, Station Biologique de Roscoff, UMR 7144, ECOMAP, Roscoff, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara GOSEE, Paris, France
| | - Michal Kucera
- MARUM Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, Bremen, Germany
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Mixotrophy in nanoflagellates across environmental gradients in the ocean. Proc Natl Acad Sci U S A 2019; 116:6211-6220. [PMID: 30760589 DOI: 10.1073/pnas.1814860116] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Mixotrophy, the combination of autotrophic and heterotrophic nutrition, is a common trophic strategy among unicellular eukaryotes in the ocean. There are a number of hypotheses about the conditions that select for mixotrophy, and field studies have documented the prevalence of mixotrophy in a range of environments. However, there is currently little evidence for how mixotrophy varies across environmental gradients, and whether empirical patterns support theoretical predictions. Here I synthesize experiments that have quantified the abundance of phototrophic, mixotrophic, and heterotrophic nanoflagellates, to ask whether there are broad patterns in the prevalence of mixotrophy (relative to pure autotrophy and heterotrophy), and to ask whether observed patterns are consistent with a trait-based model of trophic strategies. The data suggest that mixotrophs increase in abundance at lower latitudes, while autotrophs and heterotrophs do not, and that this may be driven by increased light availability. Both mixotrophs and autotrophs increase greatly in productive coastal environments, while heterotrophs increase only slightly. These patterns are consistent with a model of resource competition in which nutrients and carbon can both limit growth and mixotrophs experience a trade-off in allocating biomass to phagotrophy vs. autotrophic functions. Importantly, mixotrophy is selected for under a range of conditions even when mixotrophs experience a penalty for using a generalist trophic strategy, due to the synergy between photosynthetically derived carbon and prey-derived nutrients. For this reason mixotrophy is favored relative to specialist strategies by increased irradiance, while at the same time increased nutrient supply increases the competitive ability of mixotrophs against heterotrophs.
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Faure E, Not F, Benoiston AS, Labadie K, Bittner L, Ayata SD. Mixotrophic protists display contrasted biogeographies in the global ocean. ISME JOURNAL 2019; 13:1072-1083. [PMID: 30643201 DOI: 10.1038/s41396-018-0340-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 12/13/2018] [Accepted: 12/13/2018] [Indexed: 12/21/2022]
Abstract
Mixotrophy, or the ability to acquire carbon from both auto- and heterotrophy, is a widespread ecological trait in marine protists. Using a metabarcoding dataset of marine plankton from the global ocean, 318,054 mixotrophic metabarcodes represented by 89,951,866 sequences and belonging to 133 taxonomic lineages were identified and classified into four mixotrophic functional types: constitutive mixotrophs (CM), generalist non-constitutive mixotrophs (GNCM), endo-symbiotic specialist non-constitutive mixotrophs (eSNCM), and plastidic specialist non-constitutive mixotrophs (pSNCM). Mixotrophy appeared ubiquitous, and the distributions of the four mixotypes were analyzed to identify the abiotic factors shaping their biogeographies. Kleptoplastidic mixotrophs (GNCM and pSNCM) were detected in new zones compared to previous morphological studies. Constitutive and non-constitutive mixotrophs had similar ranges of distributions. Most lineages were evenly found in the samples, yet some of them displayed strongly contrasted distributions, both across and within mixotypes. Particularly divergent biogeographies were found within endo-symbiotic mixotrophs, depending on the ability to form colonies or the mode of symbiosis. We showed how metabarcoding can be used in a complementary way with previous morphological observations to study the biogeography of mixotrophic protists and to identify key drivers of their biogeography.
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Affiliation(s)
- Emile Faure
- Sorbonne Université, CNRS, Laboratoire d'océanographie de Villefranche, LOV, 06230, Villefranche-sur-Mer, France. .,Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, CP 50, 57 rue Cuvier, 75005, Paris, France.
| | - Fabrice Not
- Sorbonne Université, CNRS, UMR7144 Adaptation and Diversity in Marine Environment (AD2M) Laboratory, Ecology of Marine Plankton team, Station Biologique de Roscoff, Place Georges Teissier, 29680, Roscoff, France
| | - Anne-Sophie Benoiston
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, CP 50, 57 rue Cuvier, 75005, Paris, France
| | - Karine Labadie
- Genoscope, Institut de biologie François-Jacob, Commissariat à l'Energie Atomique (CEA), Evry, France, 91057, Evry, France
| | - Lucie Bittner
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, CP 50, 57 rue Cuvier, 75005, Paris, France
| | - Sakina-Dorothée Ayata
- Sorbonne Université, CNRS, Laboratoire d'océanographie de Villefranche, LOV, 06230, Villefranche-sur-Mer, France.,Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, CP 50, 57 rue Cuvier, 75005, Paris, France
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