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Behrenfeld MJ, Bisson KM. Neutral Theory and Plankton Biodiversity. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:283-305. [PMID: 37368954 DOI: 10.1146/annurev-marine-112122-105229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
The biodiversity of the plankton has been interpreted largely through the monocle of competition. The spatial distancing of phytoplankton in nature is so large that cell boundary layers rarely overlap, undermining opportunities for resource-based competitive exclusion. Neutral theory accounts for biodiversity patterns based purely on random birth, death, immigration, and speciation events and has commonly served as a null hypothesis in terrestrial ecology but has received comparatively little attention in aquatic ecology. This review summarizes basic elements of neutral theory and explores its stand-alone utility for understanding phytoplankton diversity. A theoretical framework is described entailing a very nonneutral trophic exclusion principle melded with the concept of ecologically defined neutral niches. This perspective permits all phytoplankton size classes to coexist at any limiting resource level, predicts greater diversity than anticipated from readily identifiable environmental niches but less diversity than expected from pure neutral theory, and functions effectively in populations of distantly spaced individuals.
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Affiliation(s)
- Michael J Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA; ,
| | - Kelsey M Bisson
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA; ,
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Sengupta A, Dhar J, Danza F, Ghoshal A, Müller S, Kakavand N. Active reconfiguration of cytoplasmic lipid droplets governs migration of nutrient-limited phytoplankton. SCIENCE ADVANCES 2022; 8:eabn6005. [PMID: 36332020 DOI: 10.1126/sciadv.abn6005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Nutrient availability, along with light and temperature, drives marine primary production. The ability to migrate vertically, a critical trait of motile phytoplankton, allows species to optimize nutrient uptake, storage, and growth. However, this traditional view discounts the possibility that migration in nutrient-limited waters may be actively modulated by the emergence of energy-storing organelles. Here, we report that bloom-forming raphidophytes harness energy-storing cytoplasmic lipid droplets (LDs) to biomechanically regulate vertical migration in nutrient-limited settings. LDs grow and translocate directionally within the cytoplasm, steering strain-specific shifts in the speed, trajectory, and stability of swimming cells. Nutrient reincorporation restores their swimming traits, mediated by an active reconfiguration of LD size and coordinates. A mathematical model of cell mechanics establishes the mechanistic coupling between intracellular changes and emergent migratory behavior. Amenable to the associated photophysiology, LD-governed behavioral shift highlights an exquisite microbial strategy toward niche expansion and resource optimization in nutrient-limited oceans.
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Affiliation(s)
- Anupam Sengupta
- Physics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, 162A, Avenue de la Faïencerie, 1511 Luxembourg City, Luxembourg
| | - Jayabrata Dhar
- Physics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, 162A, Avenue de la Faïencerie, 1511 Luxembourg City, Luxembourg
| | - Francesco Danza
- Physics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, 162A, Avenue de la Faïencerie, 1511 Luxembourg City, Luxembourg
| | - Arkajyoti Ghoshal
- Physics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, 162A, Avenue de la Faïencerie, 1511 Luxembourg City, Luxembourg
| | - Sarah Müller
- Physics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, 162A, Avenue de la Faïencerie, 1511 Luxembourg City, Luxembourg
- Swiss Nanoscience lnstitute, University of Basel, 82, Klingelbergslrasse, 4056 Basel, Switzerland
| | - Narges Kakavand
- Physics of Living Matter, Department of Physics and Materials Science, University of Luxembourg, 162A, Avenue de la Faïencerie, 1511 Luxembourg City, Luxembourg
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Rowlett J, Karlsson CJ, Nursultanov M. Diversity strengthens competing teams. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211916. [PMID: 35958087 PMCID: PMC9363986 DOI: 10.1098/rsos.211916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
How does the composition of a collection of individuals affect its outcome in competition with other collections of individuals? Assuming that individuals can be different, we develop a model to interpolate between individual-level interactions and collective-level consequences. Rooted in theoretical mathematics, the model is not constrained to any specific context. Potential applications include research, education, sports, politics, ecology, agriculture, algorithms and finance. Our first main contribution is a game theoretic model that interpolates between the internal composition of an ensemble of individuals and the repercussions for the ensemble as a whole in competition with others. The second main contribution is the rigorous identification of all equilibrium points and strategies. These equilibria suggest a mechanistic underpinning for biological and physical systems to tend towards increasing diversity due to the strength it imparts to the system in competition with others.
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Affiliation(s)
- J. Rowlett
- Mathematical Sciences, Chalmers University of Technology and the University of Gothenburg, 41296 Gothenburg, Sweden
| | - C. J. Karlsson
- Mathematical Sciences, Chalmers University of Technology and the University of Gothenburg, 41296 Gothenburg, Sweden
| | - M. Nursultanov
- Department of Mathematics and Statistics, University of Helsinki, PO Box 68, Helsinki FI-00014, Finland
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Ward BA, Collins S. Rapid evolution allows coexistence of highly divergent lineages within the same niche. Ecol Lett 2022; 25:1839-1853. [PMID: 35759351 PMCID: PMC9543677 DOI: 10.1111/ele.14061] [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: 01/03/2022] [Revised: 05/11/2022] [Accepted: 05/30/2022] [Indexed: 01/02/2023]
Abstract
Marine microbial communities are extremely complex and diverse. The number of locally coexisting species often vastly exceeds the number of identifiable niches, and taxonomic composition often appears decoupled from local environmental conditions. This is contrary to the view that environmental conditions should select for a few locally well-adapted species. Here we use an individual-based eco-evolutionary model to show that virtually unlimited taxonomic diversity can be supported in highly evolving assemblages, even in the absence of niche separation. With a steady stream of heritable changes to phenotype, competitive exclusion may be weakened, allowing sustained coexistence of nearly neutral phenotypes with highly divergent lineages. This behaviour is robust even to abrupt environmental perturbations that might be expected to cause strong selection pressure and an associated loss of diversity. We, therefore, suggest that rapid evolution and individual-level variability are key drivers of species coexistence and maintenance of microbial biodiversity.
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Affiliation(s)
- Ben A Ward
- School of Ocean and Earth Science, University of Southampton, Southampton, UK
| | - Sinead Collins
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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