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Jacob S, Dupont L, Haegeman B, Thierry M, Campana JLM, Legrand D, Cote J, Raffard A. Phenotypic plasticity and the effects of thermal fluctuations on specialists and generalists. Proc Biol Sci 2024; 291:20240256. [PMID: 38889786 DOI: 10.1098/rspb.2024.0256] [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: 02/01/2024] [Accepted: 04/17/2024] [Indexed: 06/20/2024] Open
Abstract
Classical theories predict that relatively constant environments should generally favour specialists, while fluctuating environments should be selected for generalists. However, theoretical and empirical results have pointed out that generalist organisms might, on the contrary, perform poorly under fluctuations. In particular, if generalism is underlaid by phenotypic plasticity, performance of generalists should be modulated by the temporal characteristics of environmental fluctuations. Here, we used experiments in microcosms of Tetrahymena thermophila ciliates and a mathematical model to test whether the period or autocorrelation of thermal fluctuations mediate links between the level of generalism and the performance of organisms under fluctuations. In the experiment, thermal fluctuations consistently impeded performance compared with constant conditions. However, the intensity of this effect depended on the level of generalism: while the more specialist strains performed better under fast or negatively autocorrelated fluctuations, plastic generalists performed better under slow or positively autocorrelated fluctuations. Our model suggests that these effects of fluctuations on organisms' performance may result from a time delay in the expression of plasticity, restricting its benefits to slow enough fluctuations. This study points out the need to further investigate the temporal dynamics of phenotypic plasticity to better predict its fitness consequences under environmental fluctuations.
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Affiliation(s)
- Staffan Jacob
- Station d'Écologie Théorique et Expérimentale, UAR2029, CNRS, Moulis 09200, France
| | - Léonard Dupont
- Station d'Écologie Théorique et Expérimentale, UAR2029, CNRS, Moulis 09200, France
| | - Bart Haegeman
- CNRS/Sorbonne Université, UMR7621 Laboratoire d'Océanographie Microbienne, Banyuls-sur-Mer, France
| | - Mélanie Thierry
- Station d'Écologie Théorique et Expérimentale, UAR2029, CNRS, Moulis 09200, France
| | - Julie L M Campana
- Station d'Écologie Théorique et Expérimentale, UAR2029, CNRS, Moulis 09200, France
| | - Delphine Legrand
- Station d'Écologie Théorique et Expérimentale, UAR2029, CNRS, Moulis 09200, France
| | - Julien Cote
- Centre de Recherche sur la Biodiversité et l'Environnement (CRBE), UMR 5300, CNRS-IRD-TINP-UT3, Toulouse 31062 Cedex 9, France
| | - Allan Raffard
- Université catholique de Louvain, Earth and Life Institute, Biodiversity Research Centre, Louvain-la-Neuve, Belgium
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Xie J, Wang T, Zhang P, Zhang H, Wang H, Wang K, Zhang M, Xu J. Effects of multiple stressors on freshwater food webs: Evidence from a mesocosm experiment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 348:123819. [PMID: 38508368 DOI: 10.1016/j.envpol.2024.123819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/26/2024] [Accepted: 03/17/2024] [Indexed: 03/22/2024]
Abstract
Natural and anthropogenic pressures exert influence on ecosystem structure and function by affecting the physiology and behavior of organisms, as well as the trophic interactions within assemblages. Therefore, understanding how multiple stressors affect aquatic ecosystems can improve our ability to manage and protect these ecosystems and contribute to understanding fundamental ecological principles. Here, we conducted a mesocosm experiment to ascertain the individual and combined effects of multiple stressors on trophic interactions within species in freshwater ecosystems. Furthermore, we investigated how species respond to such changes by adapting their food resources. To mimic a realistic food web, we selected fish and shrimp as top predators, gastropods, zooplankton and zoobenthos as intermediate consumers, with producers (macrophytes, periphyton and phytoplankton) and detritus as basal resources. Twelve different treatments included a control, nutrient loading only, herbicide exposure only, and a combination of nutrient loading and herbicide exposure, each replicated under ambient temperature, constant warming and multiple heat waves to simulate environmental stressors. Our results demonstrated that antagonistic interactions between environmental stressors were widespread in trophic interactions, with a more pronounced and less intense impact observed for the high trophic level species. The responses of freshwater communities to environmental stressors are complex, involving direct effects on individual species as well as indirect effects through species interactions. Moreover, our results confirmed that the combinations of stressors, but not individual stressors, led to a shift to herbivory in top predators, indicating that multiple stressors can be more detrimental to organisms than individual stressors alone. These findings elucidate how changes in the resource utilization of species induced by environmental stressors can potentially influence species interactions and the structural dynamics of food webs in freshwater ecosystems.
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Affiliation(s)
- Jiayi Xie
- Key Laboratory of Lake and Watershed Science for Water Security, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; University of Chinese Academy of Sciences, Beijing, PR China.
| | - Tao Wang
- Key Laboratory of Lake and Watershed Science for Water Security, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; University of Chinese Academy of Sciences, Beijing, PR China.
| | - Peiyu Zhang
- Key Laboratory of Lake and Watershed Science for Water Security, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
| | - Huan Zhang
- Key Laboratory of Lake and Watershed Science for Water Security, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
| | - Huan Wang
- Key Laboratory of Lake and Watershed Science for Water Security, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, PR China.
| | - Kang Wang
- Key Laboratory of Lake and Watershed Science for Water Security, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China; University of Chinese Academy of Sciences, Beijing, PR China.
| | - Min Zhang
- College of Fisheries, Hubei Provincial Engineering Laboratory for Pond Aquaculture, Freshwater Aquaculture Collaborative Innovation Centre of Hubei Province, Huazhong Agricultural University, Wuhan, PR China.
| | - Jun Xu
- Key Laboratory of Lake and Watershed Science for Water Security, Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
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3
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Kilner CL, Carrell AA, Wieczynski DJ, Votzke S, DeWitt K, Yammine A, Shaw J, Pelletier DA, Weston DJ, Gibert JP. Temperature and CO 2 interactively drive shifts in the compositional and functional structure of peatland protist communities. GLOBAL CHANGE BIOLOGY 2024; 30:e17203. [PMID: 38433341 DOI: 10.1111/gcb.17203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 01/20/2024] [Accepted: 01/26/2024] [Indexed: 03/05/2024]
Abstract
Microbes affect the global carbon cycle that influences climate change and are in turn influenced by environmental change. Here, we use data from a long-term whole-ecosystem warming experiment at a boreal peatland to answer how temperature and CO2 jointly influence communities of abundant, diverse, yet poorly understood, non-fungi microbial Eukaryotes (protists). These microbes influence ecosystem function directly through photosynthesis and respiration, and indirectly, through predation on decomposers (bacteria and fungi). Using a combination of high-throughput fluid imaging and 18S amplicon sequencing, we report large climate-induced, community-wide shifts in the community functional composition of these microbes (size, shape, and metabolism) that could alter overall function in peatlands. Importantly, we demonstrate a taxonomic convergence but a functional divergence in response to warming and elevated CO2 with most environmental responses being contingent on organismal size: warming effects on functional composition are reversed by elevated CO2 and amplified in larger microbes but not smaller ones. These findings show how the interactive effects of warming and rising CO2 levels could alter the structure and function of peatland microbial food webs-a fragile ecosystem that stores upwards of 25% of all terrestrial carbon and is increasingly threatened by human exploitation.
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Affiliation(s)
- Christopher L Kilner
- Department of Biology, Duke University, Durham, North Carolina, USA
- Bird Conservancy of the Rockies, Fort Collins, Colorado, USA
| | - Alyssa A Carrell
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | | | - Samantha Votzke
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Katrina DeWitt
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Andrea Yammine
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Jonathan Shaw
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Dale A Pelletier
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - David J Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Jean P Gibert
- Department of Biology, Duke University, Durham, North Carolina, USA
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4
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Raffard A, Jacob S, Schtickzelle N. Non-genetic phenotypic variability affects populations and communities in protist microcosms. J Anim Ecol 2024; 93:221-230. [PMID: 38192091 DOI: 10.1111/1365-2656.14036] [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: 04/07/2023] [Accepted: 11/27/2023] [Indexed: 01/10/2024]
Abstract
Intraspecific trait variation (ITV), potentially driven by genetic and non-genetic mechanisms, can underlie variability in resource acquisition, individual fitness and ecological interactions. Impacts of ITV at higher levels of biological organizations are hence likely, but up-scaling our knowledge about ITV importance to communities and comparing its relative effects at population and community levels has rarely been investigated. Here, we tested the effects of genetic and non-genetic ITV on morphological traits in microcosms of protist communities by contrasting the effects of strains showing different ITV levels (i.e. trait averages and variance) on population growth, community composition and biomass production. We found that genetic and non-genetic ITV can lead to different effects on populations and communities across several generations. Furthermore, the effects of ITV declined across levels of biological organization: ITV directly altered population performance, with cascading but indirect consequences for community composition and biomass productivity. Overall, these results show that the drivers of ITV can have distinct effects on populations and communities, with cascading impacts on higher levels of biological organization that might mediate biodiversity-ecosystem functioning relationships.
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Affiliation(s)
- Allan Raffard
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Staffan Jacob
- CNRS, Station d'Écologie Théorique et Expérimentale du CNRS à Moulis, UAR-5321, Moulis, France
| | - Nicolas Schtickzelle
- Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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5
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Zheng B, He S, Zhao L, Li J, Du Y, Li Y, Shi J, Wu Z. Does temperature favour the spread of Raphidiopsis raciborskii, an invasive bloom-forming cyanobacterium, by altering cellular trade-offs? HARMFUL ALGAE 2023; 124:102406. [PMID: 37164561 DOI: 10.1016/j.hal.2023.102406] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/08/2023] [Accepted: 02/14/2023] [Indexed: 05/12/2023]
Abstract
As a tropical filamentous cyanobacterium, Raphidiopsis raciborskii has attracted much attention due to its expansion and toxin production. However, the mechanisms of its expansion to temperate regions have not been studied in detail. To address the potential strategies, the physiological and metabolomic profiles of R. raciborskii FACHB 1096 isolated from a temperate lake in China were determined and measured at different temperatures (10 °C, 15 °C, 20 °C, 25 °C, and 32 °C). The results demonstrated that temperature significantly changed cell viability, chlorophyll a content, specific growth rate, Chl a fluorescence, and filamentous shape of R. raciborskii. Low temperature decreased cell viability, specific growth rate, and photosynthetic efficiency, while the proportion of akinete and carbon fixation per unit cell were significantly increased compared with high temperature (32 °C). A constructed unimodal model indicated that filament length, cell volume, and cell length/width of R. raciborskii were significantly reduced in both high and low temperature environments. Under low-temperature conditions, R. raciborskii suffered different degrees of oxidative damage and produced corresponding antioxidant substances to resist oxidative stress, suggesting that low temperature changes the metabolic level of the cells, causing the cells to gradually switch from development to defense. Metabolomic data further confirmed that temperature change induced shifts in metabolic pathways in R. raciborskii, including starch and sucrose metabolic pathways, glutathione metabolic pathways, and the pentose phosphate pathways (PPP), as well as metabolic pathways related to the tricarboxylic acid (TCA) cycle. Our results indicated that the trade-offs of R. raciborskii cells among the growth, cell size, and metabolites can be significantly regulated by temperature, with broad implications for its global expansion in temperate waterbodies.
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Affiliation(s)
- Baohai Zheng
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Shuhan He
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Lu Zhao
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Jiaxin Li
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Yuxin Du
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Yuxin Li
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Junqiong Shi
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Zhongxing Wu
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, 400715, China.
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6
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Raffard A, Campana JLM, Legrand D, Schtickzelle N, Jacob S. Resident-Disperser Differences and Genetic Variability Affect Communities in Microcosms. Am Nat 2023; 201:363-375. [PMID: 36848519 DOI: 10.1086/722750] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractDispersal is a key process mediating ecological and evolutionary dynamics. Its effects on the dynamics of spatially structured systems, population genetics, and species range distribution can depend on phenotypic differences between dispersing and nondispersing individuals. However, scaling up the importance of resident-disperser differences to communities and ecosystems has rarely been considered, in spite of intraspecific phenotypic variability being an important factor mediating community structure and productivity. Here, we used the ciliate Tetrahymena thermophila, in which phenotypic traits are known to differ between residents and dispersers, to test (i) whether these resident-disperser differences affect biomass and composition in competitive communities composed of four other Tetrahymena species and (ii) whether these effects are genotype dependent. We found that dispersers led to a lower community biomass compared with residents. This effect was highly consistent across the 20 T. thermophila genotypes used, despite intraspecific variability in resident-disperser phenotypic differences. We also found a significant genotypic effect on biomass production, showing that intraspecific variability has consequences for communities. Our study suggests that individual dispersal strategy can scale up to community productivity in a predictable way, opening new perspectives to the functioning of spatially structured ecosystems.
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7
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Han ZY, Wieczynski DJ, Yammine A, Gibert JP. Temperature and nutrients drive eco-phenotypic dynamics in a microbial food web. Proc Biol Sci 2023; 290:20222263. [PMID: 36722083 PMCID: PMC9890118 DOI: 10.1098/rspb.2022.2263] [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: 11/08/2022] [Accepted: 01/03/2023] [Indexed: 02/02/2023] Open
Abstract
Anthropogenic increases in temperature and nutrient loads will likely impact food web structure and stability. Although their independent effects have been reasonably well studied, their joint effects-particularly on coupled ecological and phenotypic dynamics-remain poorly understood. Here we experimentally manipulated temperature and nutrient levels in microbial food webs and used time-series analysis to quantify the strength of reciprocal effects between ecological and phenotypic dynamics across trophic levels. We found that (1) joint-often interactive-effects of temperature and nutrients on ecological dynamics are more common at higher trophic levels, (2) temperature and nutrients interact to shift the relative strength of top-down versus bottom-up control, and (3) rapid phenotypic change mediates observed ecological responses to changes in temperature and nutrients. Our results uncover how feedback between ecological and phenotypic dynamics mediate food web responses to environmental change. This suggests important but previously unknown ways that temperature and nutrients might jointly control the rapid eco-phenotypic feedback that determine food web dynamics in a changing world.
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Affiliation(s)
- Ze-Yi Han
- Department of Biology, Duke University, Durham, NC, USA
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8
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Rocca JD, Yammine A, Simonin M, Gibert JP. Protist Predation Influences the Temperature Response of Bacterial Communities. Front Microbiol 2022; 13:847964. [PMID: 35464948 PMCID: PMC9022080 DOI: 10.3389/fmicb.2022.847964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 03/08/2022] [Indexed: 01/04/2023] Open
Abstract
Temperature strongly influences microbial community structure and function, in turn contributing to global carbon cycling that can fuel further warming. Recent studies suggest that biotic interactions among microbes may play an important role in determining the temperature responses of these communities. However, how predation regulates these microbiomes under future climates is still poorly understood. Here, we assess whether predation by a key global bacterial consumer-protists-influences the temperature response of the community structure and function of a freshwater microbiome. To do so, we exposed microbial communities to two cosmopolitan protist species-Tetrahymena thermophila and Colpidium sp.-at two different temperatures, in a month-long microcosm experiment. While microbial biomass and respiration increased with temperature due to community shifts, these responses changed over time and in the presence of protists. Protists influenced microbial biomass and respiration rate through direct and indirect effects on bacterial community structure, and predator presence actually reduced microbial respiration at elevated temperature. Indicator species analyses showed that these predator effects were mostly determined by phylum-specific bacterial responses to protist density and cell size. Our study supports previous findings that temperature is an important driver of microbial communities but also demonstrates that the presence of a large predator can mediate these responses to warming.
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Affiliation(s)
- Jennifer D. Rocca
- Department of Biology, Duke University, Durham, NC, United States
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
| | - Andrea Yammine
- Department of Biology, Duke University, Durham, NC, United States
| | - Marie Simonin
- Department of Biology, Duke University, Durham, NC, United States
- University of Angers, Institut Agro, Institut National de la Recherche Agronomique, L’Institut de Recherche en Horticulture et Semences, Structure Fédérative de Recherche Qualité et Santé du Végétal, Angers, France
| | - Jean P. Gibert
- Department of Biology, Duke University, Durham, NC, United States
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9
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Linking species traits and demography to explain complex temperature responses across levels of organization. Proc Natl Acad Sci U S A 2021; 118:2104863118. [PMID: 34642248 DOI: 10.1073/pnas.2104863118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2021] [Indexed: 11/18/2022] Open
Abstract
Microbial communities regulate ecosystem responses to climate change. However, predicting these responses is challenging because of complex interactions among processes at multiple levels of organization. Organismal traits that determine individual performance and ecological interactions are essential for scaling up environmental responses from individuals to ecosystems. We combine protist microcosm experiments and mathematical models to show that key traits-cell size, shape, and contents-each explain different aspects of species' demographic responses to changes in temperature. These differences in species' temperature responses have complex cascading effects across levels of organization-causing nonlinear shifts in total community respiration rates across temperatures via coordinated changes in community composition, equilibrium densities, and community-mean species mass in experimental protist communities that tightly match theoretical predictions. Our results suggest that traits explain variation in population growth, and together, these two factors scale up to influence community- and ecosystem-level processes across temperatures. Connecting the multilevel microbial processes that ultimately influence climate in this way will help refine predictions about complex ecosystem-climate feedbacks and the pace of climate change itself.
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10
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Salsbery ME, DeLong JP. Thermal adaptation in a holobiont accompanied by phenotypic changes in an endosymbiont. Evolution 2021; 75:2074-2084. [PMID: 34192342 DOI: 10.1111/evo.14301] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 06/14/2021] [Indexed: 11/30/2022]
Abstract
How and if organisms can adapt to changing temperatures has drastic consequences for the natural world. Thermal adaptation involves finding a match between temperatures permitting growth and the expected temperature distribution of the environment. However, if and how this match is achieved, and how tightly linked species change together, is poorly understood. Paramecium bursaria is a ciliate that has a tight physiological interaction with endosymbiotic green algae (zoochlorellae). We subjected a wild population of P. bursaria to a cold and warm climate (20 and 32℃) for ∼300 generations. We then measured the thermal performance curve (TPC) for intrinsic rate of growth (rmax ) for these evolved lines across temperatures. We also evaluated number and size of the zoochlorellae populations within paramecia cells. TPCs for warm-adapted populations were shallower and broader than TPCs of cold-adapted populations, indicating that the warm populations adapted by moving along a thermal generalist/specialist trade off rather than right-shifting the TPC. Zoochlorellae populations within cold-adapted paramecia had fewer and larger zoochlorellae than hot-adapted paramecia, indicating phenotypic shifts in the endosymbiont accompany thermal adaptation in the host. Our results provide new and novel insight into how species involved in complex interactions will be affected by continuing increasing global temperatures.
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Affiliation(s)
- Miranda E Salsbery
- Department of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588
| | - John P DeLong
- Department of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588
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11
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Tan H, Hirst AG, Atkinson D, Kratina P. Body size and shape responses to warming and resource competition. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13789] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Hanrong Tan
- School of Biological and Chemical Sciences Queen Mary University of London London UK
| | - Andrew G. Hirst
- School of Animal, Rural and Environmental Sciences Nottingham Trent University Southwell UK
- Centre for Ocean Life National Institute for Aquatic ResourcesTechnical University of Denmark Lyngby Denmark
| | - David Atkinson
- Department of Evolution, Ecology and Behaviour University of Liverpool Liverpool UK
| | - Pavel Kratina
- School of Biological and Chemical Sciences Queen Mary University of London London UK
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12
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DeLong JP, Lyon S. Temperature alters the shape of predator-prey cycles through effects on underlying mechanisms. PeerJ 2020; 8:e9377. [PMID: 32596054 PMCID: PMC7307560 DOI: 10.7717/peerj.9377] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/27/2020] [Indexed: 12/27/2022] Open
Abstract
Background Predicting the effects of climate warming on the dynamics of ecological systems requires understanding how temperature influences birth rates, death rates and the strength of species interactions. The temperature dependance of these processes—which are the underlying mechanisms of ecological dynamics—is often thought to be exponential or unimodal, generally supported by short-term experiments. However, ecological dynamics unfold over many generations. Our goal was to empirically document shifts in predator–prey cycles over the full range of temperatures that can possibly support a predator–prey system and then to uncover the effect of temperature on the underlying mechanisms driving those changes. Methods We measured the population dynamics of the Didinium-Paramecium predator–prey system across a wide range of temperatures to reveal systematic changes in the dynamics of the system. We then used ordinary differential equation fitting to estimate parameters of a model describing the dynamics, and used these estimates to assess the long-term temperature dependance of all the underlying mechanisms. Results We found that predator–prey cycles shrank in state space from colder to hotter temperatures and that both cycle period and amplitude varied with temperature. Model parameters showed mostly unimodal responses to temperature, with one parameter (predator mortality) increasing monotonically with temperature and one parameter (predator conversion efficiency) invariant with temperature. Our results indicate that temperature can have profound, systematic effects on ecological dynamics, and these can arise through diverse and simultaneous changes in multiple underlying mechanisms. Predicting the effects of temperature on ecological dynamics may require additional investigation into how the underlying drivers of population dynamics respond to temperature beyond a short-term, acute response.
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Affiliation(s)
- John P DeLong
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Shelby Lyon
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
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13
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Uiterwaal SF, Lagerstrom IT, Luhring TM, Salsbery ME, DeLong JP. Trade-offs between morphology and thermal niches mediate adaptation in response to competing selective pressures. Ecol Evol 2020; 10:1368-1377. [PMID: 32076520 PMCID: PMC7029080 DOI: 10.1002/ece3.5990] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 12/09/2019] [Accepted: 12/16/2019] [Indexed: 01/30/2023] Open
Abstract
The effects of climate change-such as increased temperature variability and novel predators-rarely happen in isolation, but it is unclear how organisms cope with multiple stressors simultaneously. To explore this, we grew replicate Paramecium caudatum populations in either constant or variable temperatures and exposed half to predation. We then fit thermal performance curves (TPCs) of intrinsic growth rate (r max) for each replicate population (N = 12) across seven temperatures (10°C-38°C). TPCs of P. caudatum exposed to both temperature variability and predation responded only to one or the other (but not both), resulting in unpredictable outcomes. These changes in TPCs were accompanied by changes in cell morphology. Although cell volume was conserved across treatments, cells became narrower in response to temperature variability and rounder in response to predation. Our findings suggest that predation and temperature variability produce conflicting pressures on both thermal performance and cell morphology. Lastly, we found a strong correlation between changes in cell morphology and TPC parameters in response to predation, suggesting that responses to opposing selective pressures could be constrained by trade-offs. Our results shed new light on how environmental and ecological pressures interact to elicit changes in characteristics at both the individual and population levels. We further suggest that morphological responses to interactive environmental forces may modulate population-level responses, making prediction of long-term responses to environmental change challenging.
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Affiliation(s)
| | - Ian T. Lagerstrom
- School of Biological SciencesUniversity of Nebraska ‐ LincolnLincolnNEUSA
| | - Thomas M. Luhring
- School of Biological SciencesUniversity of Nebraska ‐ LincolnLincolnNEUSA
| | | | - John P. DeLong
- School of Biological SciencesUniversity of Nebraska ‐ LincolnLincolnNEUSA
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Baruah G, Clements CF, Ozgul A. Eco-evolutionary processes underlying early warning signals of population declines. J Anim Ecol 2019; 89:436-448. [PMID: 31433863 DOI: 10.1111/1365-2656.13097] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 07/30/2019] [Indexed: 01/01/2023]
Abstract
Environmental change can impact the stability of ecological systems and cause rapid declines in populations. Abundance-based early warning signals have been shown to precede such declines, but detection prior to wild population collapses has had limited success, leading to the development of warning signals based on shifts in distribution of fitness-related traits such as body size. The dynamics of population abundances and traits in response to external environmental perturbations are controlled by a range of underlying factors such as reproductive rate, genetic variation and plasticity. However, it remains unknown how such ecological and evolutionary factors affect the stability landscape of populations and the detectability of abundance and trait-based early warning signals. Here, we apply a trait-based demographic approach and investigate both trait and population dynamics in response to gradual and increasing changes in the environment. We explore a range of ecological and evolutionary constraints under which stability of a population may be affected. We show both analytically and with simulations that strength of abundance- and trait-based warning signals are affected by ecological and evolutionary factors. Finally, we show that combining trait- and abundance-based information improves our ability to predict population declines. Our study suggests that the inclusion of trait dynamic information alongside generic warning signals should provide more accurate forecasts of the future state of biological systems.
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Affiliation(s)
- Gaurav Baruah
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Christopher F Clements
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,School of Biological Sciences, University of Bristol, Bristol, UK
| | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
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15
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Gibert JP. Temperature directly and indirectly influences food web structure. Sci Rep 2019; 9:5312. [PMID: 30926855 PMCID: PMC6441002 DOI: 10.1038/s41598-019-41783-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 03/18/2019] [Indexed: 12/05/2022] Open
Abstract
Understanding whether and how environmental conditions may impact food web structure at a global scale is central to our ability to predict how food webs will respond to climate change. However, such an understanding is nascent. Using the best resolved available food webs to date, I address whether latitude, temperature, or both, explain the number of species and feeding interactions, the proportion of basal and top species, as well as the degree of omnivory, connectance and the number of trophic levels across food webs. I found that temperature is a more parsimonious predictor of food web structure than latitude. Temperature directly reduces the number of species, the proportion of basal species and the number of interactions while it indirectly increases omnivory levels, connectance and trophic level through its direct effects on the fraction and number of basal species. While direct impacts of temperature are routinely taken into account to predict how ecosystems may respond to global climate change, indirect effects have been largely overlooked. These results thus suggest that food webs may be affected by a combination of biotic and abiotic conditions, both directly and indirectly, in a changing world.
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Affiliation(s)
- Jean P Gibert
- Department of Biology, Duke University, Durham, NC, 27708, USA.
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Gibert JP, Yeakel JD. Eco-Evolutionary Origins of Diverse Abundance, Biomass, and Trophic Structures in Food Webs. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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17
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Brückner A, Schuster R, Wehner K, Heethoff M. Nutritional quality modulates trait variability. Front Zool 2018; 15:50. [PMID: 30534185 PMCID: PMC6282258 DOI: 10.1186/s12983-018-0297-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/23/2018] [Indexed: 12/20/2022] Open
Abstract
Background Trait based functional and community ecology is en vogue. Most studies, however, ignore phenotypical diversity by characterizing entire species considering only trait means rather than their variability. Phenotypical variability may arise from genotypical differences or from ecological factors (e.g., nutritionally imbalanced diet), and these causes can usually not be separated in natural populations. We used a single genotype from a parthenogenetic model system (the oribatid mite Archegozetes longisetosus Aoki) to exclude genotypical differences. We investigated patterns of dietary (10 different food treatments) induced trait variation by measuring the response of nine different traits (relating to life history, morphology or exocrine gland chemistry). Results Nutritional quality (approximated by carbon-to-nitrogen ratios) influenced all trait means and their variation. Some traits were more prone to variation than others. Furthermore, the “threshold elemental ratio”- rule of element stoichiometry applied to phenotypic trait variation. Imbalanced food (i.e. food not able to fully meet the nutritional demands of an animal) led to lower trait mean values, but also to a higher variation of traits. Conclusion Imbalanced food led not only to lower trait value averages, but also to higher trait variability. There was a negative relationship between both parameters, indicating a direct link of both, average trait levels and trait variation to nutritional quality. Hence, variation of trait means may be a predictor for general food quality, and further indicate trade-offs in specific traits an animal must deal with while feeding on imbalanced diets. Electronic supplementary material The online version of this article (10.1186/s12983-018-0297-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adrian Brückner
- 1Ecological Networks, Technische Universität Darmstadt, Schnittspahnstraße 3, 64287 Darmstadt, Germany.,2Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, CA 91125 USA
| | - Romina Schuster
- 1Ecological Networks, Technische Universität Darmstadt, Schnittspahnstraße 3, 64287 Darmstadt, Germany
| | - Katja Wehner
- 1Ecological Networks, Technische Universität Darmstadt, Schnittspahnstraße 3, 64287 Darmstadt, Germany
| | - Michael Heethoff
- 1Ecological Networks, Technische Universität Darmstadt, Schnittspahnstraße 3, 64287 Darmstadt, Germany
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