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Chatziefthimiou AD, Metcalf JS, Glover WB, Powell JT, Banack SA, Cox PA, Ladjimi M, Sultan AA, Chemaitelly H, Richer RA. Cyanotoxin accumulation and growth patterns of biocrust communities under variable environmental conditions. Toxicon X 2024; 23:100199. [PMID: 38974839 PMCID: PMC11225906 DOI: 10.1016/j.toxcx.2024.100199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 07/09/2024] Open
Abstract
Biocrusts dominate the soil surface in deserts and are composed of diverse microbial communities that provide important ecosystem services. Cyanobacteria in biocrusts produce many secondary metabolites, including the neurotoxins BMAA, AEG, DAB, anatoxin-a(S) (guanitoxin), and the microcystin hepatotoxins, all known or suspected to cause disease or illness in humans and other animals. We examined cyanobacterial growth and prevalence of these toxins in biocrusts at millimeter-scales, under a desert-relevant illumination gradient. In contrast to previous work, we showed that hydration had an overall positive effect on growth and toxin accumulation, that nitrogen was not correlated with growth or toxin production, and that phosphorus enrichment negatively affected AEG and BMAA concentrations. Excess illumination positively correlated with AEG, and negatively correlated with all other toxins and growth. Basic pH negatively affected only the accumulation of BMAA. Anatoxin-a(S) (guanitoxin) was not correlated with any tested variables, while microcystins were not detected in any of the samples. Concerning toxin pools, AEG and BMAA were good predictors of the presence of one another. In a newly conceptualized scheme, we integrate aspects of biocrust growth and toxin pool accumulations with arid-relevant desertification drivers.
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Affiliation(s)
| | - James S. Metcalf
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA
- Bowling Green State University, Bowling Green, OH, USA
| | | | - James T. Powell
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA
| | - Sandra A. Banack
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA
| | - Paul A. Cox
- Brain Chemistry Labs, Institute for Ethnomedicine, Jackson, WY, USA
| | - Moncef Ladjimi
- Weill Cornell Medicine – Qatar, Education City, Doha, Qatar
| | - Ali A. Sultan
- Weill Cornell Medicine – Qatar, Education City, Doha, Qatar
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2
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Cocquyt C, Verschuren D. Checklist of the diatoms (Bacillariophyta) from Lake Naivasha, Kenya, with some historical notes. PHYTOKEYS 2023; 224:101-174. [PMID: 37251510 PMCID: PMC10209617 DOI: 10.3897/phytokeys.224.98168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/20/2023] [Indexed: 05/31/2023]
Abstract
Lake Naivasha is one of only two large freshwater lakes in the Eastern Rift Valley of Kenya, East Africa. Together with its satellite lakes Crescent Island Crater, Oloidien and Sonachi, it comprises a great variety of pelagic and benthic habitats for aquatic biota, and its sediment record represents a unique archive of past climate change and long-term ecosystem dynamics in equatorial East Africa. This is particularly so because local paleoenvironmental reconstructions can be checked against historical data on the composition of aquatic fauna and flora collected in Lake Naivasha since the early 20th century. Some of the most prominent biological proxies for reconstructing past changes in lakes are diatoms (Bacillariophyta), a group of unicellular autotrophic eukaryotes of which the siliceous skeletons (valves) preserve well in lake sediments and are good indicators for, among others, climate-driven changes in salinity. However, diatom taxonomy and species concepts have changed a lot in recent decades, making it sometimes difficult for non-taxonomists to know which species are concerned in different published studies. This paper provides the currently accepted taxonomic names of the 310 specific and infraspecific diatom taxa reported from Lake Naivasha and its satellite lakes to date, together with their synonyms used in literature concerning these lakes as well as other, commonly used synonyms. Further, a short overview is given of the history of diatom research conducted on materials from Lake Naivasha and its satellite lakes. The present checklist may facilitate the identification and interpretation aspects of future diatom studies on the wider Lake Naivasha ecosystem and on other East African lakes that are less well studied.
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Affiliation(s)
- Christine Cocquyt
- Research Department, Meise Botanic Garden, 1860 Meise, BelgiumGhent UniversityGhentBelgium
- Limnology Unit, Ghent University, 9000 Gent, BelgiumMeise Botanic GardenMeiseBelgium
| | - Dirk Verschuren
- Limnology Unit, Ghent University, 9000 Gent, BelgiumMeise Botanic GardenMeiseBelgium
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3
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White BE, McIntosh AR, Febria CM, Warburton HJ. The potential role of biotic interactions in stream restoration. Restor Ecol 2021. [DOI: 10.1111/rec.13396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bridget E. White
- School of Biological Sciences University of Canterbury – Te Whare Wānanga o Waitaha Private Bag 4800 Christchurch 8140 New Zealand
| | - Angus R. McIntosh
- School of Biological Sciences University of Canterbury – Te Whare Wānanga o Waitaha Private Bag 4800 Christchurch 8140 New Zealand
| | - Catherine M. Febria
- Great Lakes Institute for Environmental Research University of Windsor 2990 Riverside Dr. W. Windsor ON N9C 1A2 Canada
| | - Helen J. Warburton
- School of Biological Sciences University of Canterbury – Te Whare Wānanga o Waitaha Private Bag 4800 Christchurch 8140 New Zealand
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4
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Barrett IC, McIntosh AR, Febria CM, Warburton HJ. Negative resistance and resilience: biotic mechanisms underpin delayed biological recovery in stream restoration. Proc Biol Sci 2021; 288:20210354. [PMID: 33784863 PMCID: PMC8059965 DOI: 10.1098/rspb.2021.0354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Traditionally, resistance and resilience are associated with good ecological health, often underpinning restoration goals. However, degraded ecosystems can also be highly resistant and resilient, making restoration difficult: degraded communities often become dominated by hyper-tolerant species, preventing recolonization and resulting in low biodiversity and poor ecosystem function. Using streams as a model, we undertook a mesocosm experiment to test if degraded community presence hindered biological recovery. We established 12 mesocosms, simulating physically healthy streams. Degraded invertebrate communities were established in half, mimicking the post-restoration scenario of physical recovery without biological recovery. We then introduced a healthy colonist community to all mesocosms, testing if degraded community presence influenced healthy community establishment. Colonists established less readily in degraded community mesocosms, with larger decreases in abundance of sensitive taxa, likely driven by biotic interactions rather than abiotic constraints. Resource depletion by the degraded community likely increased competition, driving priority effects. Colonists left by drifting, but also by accelerating development, reducing time to emergence but sacrificing larger body size. Since degraded community presence prevented colonist establishment, our experiment suggests successful restoration must address both abiotic and biotic factors, especially those that reinforce the ‘negative’ resistance and resilience which perpetuate degraded communities and are typically overlooked.
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Affiliation(s)
- Isabelle C Barrett
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Angus R McIntosh
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Catherine M Febria
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.,Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Canada
| | - Helen J Warburton
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
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5
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Van der Meeren T, Verschuren D. Zoobenthos community turnover in a 1650‐yr lake‐sediment record of climate‐driven hydrological change. Ecosphere 2021. [DOI: 10.1002/ecs2.3333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
| | - Dirk Verschuren
- Limnology Unit Department of Biology Ghent University GentB‐9000Belgium
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6
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Ruggeri P, Pasternak E, Okamura B. To remain or leave: Dispersal variation and its genetic consequences in benthic freshwater invertebrates. Ecol Evol 2019; 9:12069-12088. [PMID: 31832145 PMCID: PMC6854113 DOI: 10.1002/ece3.5656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/25/2019] [Accepted: 08/26/2019] [Indexed: 01/10/2023] Open
Abstract
Variation in dispersal capacity may influence population genetic variation and relatedness of freshwater animals thus demonstrating how life-history traits influence patterns and processes that in turn influence biodiversity. The majority of studies have focused on the consequences of dispersal variation in taxa inhabiting riverine systems whose dendritic nature and upstream/downstream gradients facilitate characterizing populations along networks. We undertook extensive, large-scale investigations of the impacts of hydrological connectivity on population genetic variation in two freshwater bryozoan species whose dispersive propagules (statoblasts) are either attached to surfaces (Fredericella sultana) or are released as buoyant stages (Cristatella mucedo) and that live primarily in either lotic (F. sultana) or lentic environments (C. mucedo). Describing population genetic structure in multiple sites characterized by varying degrees of hydrological connectivity within each of three (or four) UK regions enabled us to test the following hypotheses: (1) genetic diversity and gene flow will be more influenced by hydrological connectivity in populations of C. mucedo (because F. sultana dispersal stages are retained); (2) populations of F. sultana will be characterized by greater genetic divergence than those of C. mucedo (reflecting their relative dispersal capacities); and (3) genetic variation will be greatest in F. sultana (reflecting a propensity for genetic divergence as a result of its low dispersal potential). We found that hydrological connectivity enhanced genetic diversity and gene flow among C. mucedo populations but not in F. sultana while higher overall measures of clonal diversity and greater genetic divergence characterized populations of F. sultana. We suggest that genetic divergence over time within F. sultana populations reflects a general constraint of releasing propagules that might eventually be swept to sea when taxa inhabit running waters. In contrast, taxa that primarily inhabit lakes and ponds may colonize across hydrologically connected regions, establishing genetically related populations. Our study contributes more nuanced views about drivers of population genetic structures in passively dispersing freshwater invertebrates as outlined by the Monopolization Hypothesis (Acta Oecologica, 23, 2002, 121) by highlighting how a range of demographic and evolutionary processes reflect life-history attributes of benthic colonial invertebrates (bryozoans) and cyclically parthenogenetic zooplankton. In addition, growing evidence that genetic divergence may commonly characterize populations of diverse groups of riverine taxa suggests that organisms inhabiting lotic systems may be particularly challenged by environmental change. Such change may predispose riverine populations to extinction as a result of genetic divergence combined with limited dispersal and gene flow. OPEN RESEARCH BADGES This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at https://doi.org/10.5061/dryad.1tm8705.
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Affiliation(s)
- Paolo Ruggeri
- Department of Life SciencesNatural History MuseumLondonUK
- Laboratory of Integrative Biology of Marine ModelsStation Biologique de RoscoffCNRS‐Sorbonne UniversityRoscoffFrance
| | - Ellen Pasternak
- Department of Life SciencesNatural History MuseumLondonUK
- Zoology DepartmentOxford UniversityOxfordUK
| | - Beth Okamura
- Department of Life SciencesNatural History MuseumLondonUK
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7
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8
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Song C, Altermatt F, Pearse I, Saavedra S. Structural changes within trophic levels are constrained by within-family assembly rules at lower trophic levels. Ecol Lett 2018; 21:1221-1228. [DOI: 10.1111/ele.13091] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/10/2018] [Accepted: 04/23/2017] [Indexed: 01/28/2023]
Affiliation(s)
- Chuliang Song
- Department of Civil and Environmental Engineering; MIT; 77 Massachusetts Av. Cambridge MA 02139 USA
| | - Florian Altermatt
- Department of Aquatic Ecology; EAWAG; Überlandstrasse 133 CH-8600 Dübendorf Switzerland
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Ian Pearse
- U.S. Geological Survey; Collins Science Center; 2150 Centre Ave #C Ft Collins CO 80526 USA
| | - Serguei Saavedra
- Department of Civil and Environmental Engineering; MIT; 77 Massachusetts Av. Cambridge MA 02139 USA
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9
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Rummens K, De Meester L, Souffreau C. Inoculation history affects community composition in experimental freshwater bacterioplankton communities. Environ Microbiol 2018; 20:1120-1133. [DOI: 10.1111/1462-2920.14053] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/15/2018] [Accepted: 01/21/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Koen Rummens
- Laboratory of Aquatic Ecology, Evolution & Conservation; KU Leuven, Charles Deberiotstraat 32; 3000 Leuven Belgium
| | - Luc De Meester
- Laboratory of Aquatic Ecology, Evolution & Conservation; KU Leuven, Charles Deberiotstraat 32; 3000 Leuven Belgium
| | - Caroline Souffreau
- Laboratory of Aquatic Ecology, Evolution & Conservation; KU Leuven, Charles Deberiotstraat 32; 3000 Leuven Belgium
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10
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Viana DS, Cid B, Figuerola J, Santamaría L. Disentangling the roles of diversity resistance and priority effects in community assembly. Oecologia 2016; 182:865-75. [PMID: 27576552 DOI: 10.1007/s00442-016-3715-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 08/21/2016] [Indexed: 11/29/2022]
Abstract
The assembly of many biological communities is constrained by the resistance exerted by resident species to immigration (biotic resistance). Two important mechanisms contribute to the generation of biotic resistance: diversity resistance and priority effects. These mechanisms have been explored through theoretical models and laboratory experiments, but the importance of their interplay in the assembly of natural communities remains untested. We used a mesocosm experiment with communities of aquatic plants and zooplankton assembled from natural propagule banks to test whether and how diversity resistance, mediated by the diversity of the resident community, and priority effects, mediated by the timing of immigrants' arrival, affect the establishment of immigrant species and community diversity. In plant communities, immigration success decreased with increasing resident-species richness (diversity resistance) and arrival time (priority effects). Further, diversity resistance was stronger in communities colonized later in the season, indicating that these mechanisms interacted to reinforce biotic resistance. This interaction ultimately determined species richness and beta-diversity in plant communities. For zooplankton, in contrast, neither the diversity of resident communities nor the time of arrival affected the establishment of immigrant species. In these communities, beta-diversity was explained by species sorting, namely biotic effects mediated by plant assemblages. Our results show that the progressive buildup of communities generates an interaction between diversity resistance and priority effects that eventually determines community diversity, unless species sorting mediated by environmental filtering supersedes the effect of biotic resistance. Therefore, disentangling the mechanisms underlying biotic resistance contributes to understand how species diversity is ultimately determined.
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Affiliation(s)
- Duarte S Viana
- Estación Biológica de Doñana (EBD-CSIC), C/Américo Vespucio, s/n, 41092, Sevilla, Spain.
| | - Bertha Cid
- Mediterranean Institute for Advanced Studies (IMEDEA, CSIC-UIB), Miquel Marqués 21, Esporles, 07190, Mallorca, Balearic Islands, Spain
| | - Jordi Figuerola
- Estación Biológica de Doñana (EBD-CSIC), C/Américo Vespucio, s/n, 41092, Sevilla, Spain
| | - Luis Santamaría
- Estación Biológica de Doñana (EBD-CSIC), C/Américo Vespucio, s/n, 41092, Sevilla, Spain.,Mediterranean Institute for Advanced Studies (IMEDEA, CSIC-UIB), Miquel Marqués 21, Esporles, 07190, Mallorca, Balearic Islands, Spain
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11
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Effects of dispersal and selection on stochastic assembly in microbial communities. ISME JOURNAL 2016; 11:176-185. [PMID: 27494293 DOI: 10.1038/ismej.2016.96] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 06/02/2016] [Accepted: 06/07/2016] [Indexed: 11/08/2022]
Abstract
Stochastic processes can play an important role in microbial community assembly. Dispersal limitation is one process that can increase stochasticity and obscure relationships between environmental variables and microbial community composition, but the relationship between dispersal, selection and stochasticity has not been described in a comprehensive way. We examine how dispersal and its interactions with drift and selection alter the consistency with which microbial communities assemble using a realistic, individual-based model of microbial decomposers. Communities were assembled under different environmental conditions and dispersal rates in repeated simulations, and we examined the compositional difference among replicate communities colonizing the same type of leaf litter ('within-group distance'), as well as between-group deterministic selection. Dispersal rates below 25% turnover per year resulted in high within-group distance among communities and no significant environmental effects. As dispersal limitation was alleviated, both within- and between-group distance decreased, but despite this homogenization, deterministic environmental effects remained significant. In addition to direct effects of dispersal rate, stochasticity of community composition was influenced by an interaction between dispersal and selection strength. Specifically, communities experiencing stronger selection (less favorable litter chemistries) were more stochastic, possibly because lower biomass and richness intensified drift or priority effects. Overall, we show that dispersal rate can significantly alter patterns of community composition. Partitioning the effects of dispersal, selection and drift based on static patterns of microbial composition will be difficult, if not impossible. Experiments will be required to tease apart these complex interactions between assembly processes shaping microbial communities.
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12
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Environmental filtering determines metacommunity structure in wetland microcrustaceans. Oecologia 2016; 181:193-205. [DOI: 10.1007/s00442-015-3540-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 12/25/2015] [Indexed: 10/22/2022]
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13
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Fukami T. Historical Contingency in Community Assembly: Integrating Niches, Species Pools, and Priority Effects. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2015. [DOI: 10.1146/annurev-ecolsys-110411-160340] [Citation(s) in RCA: 861] [Impact Index Per Article: 95.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Tadashi Fukami
- Department of Biology, Stanford University, Stanford, California 94305;
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14
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Hubin E, Vanschoenwinkel B, Broersen K, De Deyn PP, Koedam N, van Nuland NA, Pauwels K. Could ecosystem management provide a new framework for Alzheimer's disease? Alzheimers Dement 2015; 12:65-74.e1. [PMID: 26341147 DOI: 10.1016/j.jalz.2015.07.491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/20/2015] [Accepted: 07/01/2015] [Indexed: 10/23/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative brain disorder that involves a plethora of molecular pathways. In the context of therapeutic treatment and biomarker profiling, the amyloid-beta (Aβ) peptide constitutes an interesting research avenue that involves interactions within a complex mixture of Aβ alloforms and other disease-modifying factors. Here, we explore the potential of an ecosystem paradigm as a novel way to consider AD and Aβ dynamics in particular. We discuss the example that the complexity of the Aβ network not only exhibits interesting parallels with the functioning of complex systems such as ecosystems but that this analogy can also provide novel insights into the neurobiological phenomena in AD and serve as a communication tool. We propose that combining network medicine with general ecosystem management principles could be a new and holistic approach to understand AD pathology and design novel therapies.
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Affiliation(s)
- Ellen Hubin
- Nanobiophysics Group, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands; Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Brussels, Belgium; Structural Biology Research Center, VIB, Brussels, Belgium
| | - Bram Vanschoenwinkel
- Plant Biology and Nature Management (APNA), Department of Biology (DBIO), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Kerensa Broersen
- Nanobiophysics Group, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands
| | - Peter P De Deyn
- Department of Physiotherapy (REVAKI), Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Department of Neurology and Memory Clinic, Middelheim General Hospital (Ziekenhuis Netwerk Antwerpen), University of Antwerp, Antwerp, Belgium; Laboratory of Neurochemistry and Behaviour, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium; Department of Neurology and Alzheimer Research Center, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - Nico Koedam
- Plant Biology and Nature Management (APNA), Department of Biology (DBIO), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Nico A van Nuland
- Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Brussels, Belgium; Structural Biology Research Center, VIB, Brussels, Belgium
| | - Kris Pauwels
- Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Brussels, Belgium; Structural Biology Research Center, VIB, Brussels, Belgium.
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15
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Jackson ST, Blois JL. Community ecology in a changing environment: Perspectives from the Quaternary. Proc Natl Acad Sci U S A 2015; 112:4915-21. [PMID: 25901314 PMCID: PMC4413336 DOI: 10.1073/pnas.1403664111] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Community ecology and paleoecology are both concerned with the composition and structure of biotic assemblages but are largely disconnected. Community ecology focuses on existing species assemblages and recently has begun to integrate history (phylogeny and continental or intercontinental dispersal) to constrain community processes. This division has left a "missing middle": Ecological and environmental processes occurring on timescales from decades to millennia are not yet fully incorporated into community ecology. Quaternary paleoecology has a wealth of data documenting ecological dynamics at these timescales, and both fields can benefit from greater interaction and articulation. We discuss ecological insights revealed by Quaternary terrestrial records, suggest foundations for bridging between the disciplines, and identify topics where the disciplines can engage to mutual benefit.
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Affiliation(s)
- Stephen T Jackson
- Southwest Climate Science Center, US Geological Survey, Tucson, AZ 85719; Department of Geosciences and School of Natural Resources and Environment, University of Arizona, Tucson, AZ 85721; and
| | - Jessica L Blois
- Life and Environmental Sciences, School of Natural Sciences, University of California, Merced CA 95343
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16
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Lievens B, Hallsworth JE, Pozo MI, Belgacem ZB, Stevenson A, Willems KA, Jacquemyn H. Microbiology of sugar-rich environments: diversity, ecology and system constraints. Environ Microbiol 2014; 17:278-98. [PMID: 25041632 DOI: 10.1111/1462-2920.12570] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/04/2014] [Accepted: 07/12/2014] [Indexed: 12/18/2022]
Abstract
Microbial habitats that contain an excess of carbohydrate in the form of sugar are widespread in the microbial biosphere. Depending on the type of sugar, prevailing water activity and other substances present, sugar-rich environments can be highly dynamic or relatively stable, osmotically stressful, and/or destabilizing for macromolecular systems, and can thereby strongly impact the microbial ecology. Here, we review the microbiology of different high-sugar habitats, including their microbial diversity and physicochemical parameters, which act to impact microbial community assembly and constrain the ecosystem. Saturated sugar beet juice and floral nectar are used as case studies to explore the differences between the microbial ecologies of low and higher water-activity habitats respectively. Nectar is a paradigm of an open, dynamic and biodiverse habitat populated by many microbial taxa, often yeasts and bacteria such as, amongst many others, Metschnikowia spp. and Acinetobacter spp., respectively. By contrast, thick juice is a relatively stable, species-poor habitat and is typically dominated by a single, xerotolerant bacterium (Tetragenococcus halophilus). A number of high-sugar habitats contain chaotropic solutes (e.g. ethyl acetate, phenols, ethanol, fructose and glycerol) and hydrophobic stressors (e.g. ethyl octanoate, hexane, octanol and isoamyl acetate), all of which can induce chaotropicity-mediated stresses that inhibit or prevent multiplication of microbes. Additionally, temperature, pH, nutrition, microbial dispersion and habitat history can determine or constrain the microbiology of high-sugar milieux. Findings are discussed in relation to a number of unanswered scientific questions.
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Affiliation(s)
- Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, B-2860, Sint-Katelijne-Waver, Belgium
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17
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Andersson MGI, Berga M, Lindström ES, Langenheder S. The spatial structure of bacterial communities is influenced by historical environmental conditions. Ecology 2014; 95:1134-40. [PMID: 25000745 DOI: 10.1890/13-1300.1] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The spatial structure of ecological communities, including that of bacteria, is often influenced by species sorting by contemporary environmental conditions. Moreover, historical processes, i.e., ecological and evolutionary events that have occurred at some point in the past, such as dispersal limitation, drift, priority effects, or selection by past environmental conditions, can be important, but are generally investigated much less. Here, we conducted a field study using 16 rock pools, where we specifically compared the importance of past vs. contemporary environmental conditions for bacterial community structure by correlating present differences in bacterial community composition among pools to environmental conditions measured on the same day, as well as to those measured 2, 4, 6, and 8 d earlier. The results prove that selection by past environmental conditions exists, since we were able to show that bacterial communities are, to a greater extent, an imprint of past compared to contemporary environmental conditions. We suggest that this is the result of a combination of different mechanisms, including priority effects that cause rapid adaptation to new environmental conditions of taxa that have been initially selected by past environmental conditions, and slower rates of turnover in community composition compared to environmental conditions.
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18
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Yin M, Gießler S, Griebel J, Wolinska J. Hybridizing Daphnia communities from ten neighbouring lakes: spatio-temporal dynamics, local processes, gene flow and invasiveness. BMC Evol Biol 2014; 14:80. [PMID: 24725969 PMCID: PMC4101843 DOI: 10.1186/1471-2148-14-80] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/04/2014] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND In natural communities of cyclical parthenogens, rapid response to environmental change is enabled by switching between two reproduction modes. While long periods of asexual reproduction allow some clones to outcompete others, and may result in "clonal erosion", sexual reproduction restores genetic variation in such systems. Moreover, sexual reproduction may result in the formation of interspecific hybrids. These hybrids can then reach high abundances, through asexual clonal reproduction. In the present study, we explored genetic variation in water fleas of the genus Daphnia. The focus was on the short-term dynamics within several clonal assemblages from the hybridizing Daphnia longispina complex and the impact of gene flow at small spatial scales. RESULTS Daphnia individuals belonged either to the parental species D. galeata and D. longispina, or to different hybrid classes, as identified by 15 microsatellite markers. The distribution and genotypic structure of parental species, but not hybrids, corresponded well with the geographical positions of the lakes. Within parental species, the genetic distance among populations of D. galeata was lower than among populations of D. longispina. Moreover, D. galeata dominance was associated with higher phosphorous load. Finally, there was no evidence for clonal erosion. CONCLUSIONS Our results suggest that the contemporary structure of hybridizing Daphnia communities from ten nearby lakes is influenced by colonization events from neighbouring habitats as well as by environmental factors. Unlike the parental species, however, there was little evidence for successful dispersal of hybrids, which seem to be produced locally. Finally, in contrast to temporary Daphnia populations, in which a decrease in clonal diversity was sometimes detectable over a single growing season, the high clonal diversity and lack of clonal erosion observed here might result from repeated hatching of sexually produced offspring. Overall, our study provides insights into spatio-temporal dynamics in a hybridizing Daphnia species complex in a recently established lake system, and relates genetic similarities of populations to a scenario of secondary invasion enhanced by environmental factors.
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Affiliation(s)
| | - Sabine Gießler
- Department Biologie II, Evolutionsökologie, Ludwig-Maximilians-Universität, Großhaderner Str, 2, 82152 Planegg-Martinsried, Germany.
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Symons CC, Arnott SE. Timing is everything: priority effects alter community invasibility after disturbance. Ecol Evol 2014; 4:397-407. [PMID: 24634724 PMCID: PMC3936386 DOI: 10.1002/ece3.940] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/25/2013] [Accepted: 10/27/2013] [Indexed: 11/24/2022] Open
Abstract
Theory suggests that communities should be more open to the establishment of regional species following disturbance because disturbance may make more resources available to dispersers. However, after an initial period of high invasibility, growth of the resident community may lead to the monopolization of local resources and decreased probability of successful colonist establishment. During press disturbances (i.e., directional environmental change), it remains unclear what effect regional dispersal will have on local community structure if the establishment of later arriving species is affected by early arriving species (i.e., if priority effects are important). To determine the relationship between time-since-disturbance and invasibility, we conducted a fully factorial field mesocosm experiment that exposed tundra zooplankton communities to two emerging stressors - nutrient and salt addition, and manipulated the arrival timing of regional dispersers. Our results demonstrate that invasibility decreases with increasing time-since-disturbance as abundance (nutrient treatments) or species richness (salt treatments) increases in the resident community. Results suggest that the relative timing of dispersal and environmental change will modify the importance of priority effects in determining species composition after a press disturbance.
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Affiliation(s)
- Celia C Symons
- Department of Biology, Queen's UniversityKingston, ON, Canada
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Tucker CM, Fukami T. Environmental variability counteracts priority effects to facilitate species coexistence: evidence from nectar microbes. Proc Biol Sci 2014; 281:20132637. [PMID: 24430846 DOI: 10.1098/rspb.2013.2637] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The order of species arrival during community assembly can greatly affect species coexistence, but the strength of these effects, known as priority effects, appears highly variable across species and ecosystems. Furthermore, the causes of this variation remain unclear despite their fundamental importance in understanding species coexistence. Here, we show that one potential cause is environmental variability. In laboratory experiments using nectar-inhabiting microorganisms as a model system, we manipulated spatial and temporal variability of temperature, and examined consequences for priority effects. If species arrived sequentially, multiple species coexisted under variable temperature, but not under constant temperature. Temperature variability prevented extinction of late-arriving species that would have been excluded owing to priority effects if temperature had been constant. By contrast, if species arrived simultaneously, species coexisted under both variable and constant temperatures. We propose possible mechanisms underlying these results using a mathematical model that incorporates contrasting effects of microbial species on nectar pH and amino acids. Overall, our findings suggest that understanding consequences of priority effects for species coexistence requires explicit consideration of environmental variability.
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Affiliation(s)
- Caroline M Tucker
- Department of Biology, Stanford University, , Stanford, CA 94305, USA, INSTAAR, University of Colorado, , 3100 Marine Street, Boulder, CO 80309, USA
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Loureiro C, Pereira JL, Pedrosa MA, Gonçalves F, Castro BB. Competitive outcome of Daphnia-Simocephalus experimental microcosms: salinity versus priority effects. PLoS One 2013; 8:e70572. [PMID: 23940594 PMCID: PMC3734296 DOI: 10.1371/journal.pone.0070572] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 06/19/2013] [Indexed: 11/22/2022] Open
Abstract
Competition is a major driving force in freshwaters, especially given the cyclic nature and dynamics of pelagic food webs. Competition is especially important in the initial species assortment during colonization and re-colonization events, which depends strongly on the environmental context. Subtle changes, such as saline intrusion, may disrupt competitive relationships and, thus, influence community composition. Bearing this in mind, our objective was to assess whether low salinity levels (using NaCl as a proxy) alter the competitive outcome (measured as the rate of population biomass increase) of Daphnia-Simocephalus experimental microcosms, taking into account interactions with priority effects (sequential species arrival order). With this approach, we aimed to experimentally demonstrate a putative mechanism of differential species sorting in brackish environments or in freshwaters facing secondary salinization. Experiments considered three salinity levels, regarding NaCl added (0.00, 0.75 and 1.50 g L−1), crossed with three competition scenarios (no priority, priority of Daphnia over Simocephalus, and vice-versa). At lower NaCl concentrations (0.00 and 0.75 g L−1), Daphnia was a significantly superior competitor, irrespective of the species inoculation order, suggesting negligible priority effects. However, the strong decrease in Daphnia population growth at 1.50 g L−1 alleviated the competitive pressure on Simocephalus, causing an inversion of the competitive outcome in favour of Simocephalus. The intensity of this inversion depended on the competition scenario. This salinity-mediated disruption of the competitive outcome demonstrates that subtle environmental changes produce indirect effects in key ecological mechanisms, thus altering community composition, which may lead to serious implications in terms of ecosystem functioning (e.g. lake regime shifts due to reduced grazing) and biodiversity.
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Affiliation(s)
- Cláudia Loureiro
- Departamento de Biologia & CESAM, Universidade de Aveiro, Aveiro, Portugal
| | - Joana L. Pereira
- Departamento de Biologia & CESAM, Universidade de Aveiro, Aveiro, Portugal
| | - M. Arminda Pedrosa
- Unidade de I&D n° 70/94– Química-Física Molecular/FC, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade de Coimbra, Coimbra, Portugal
| | - Fernando Gonçalves
- Departamento de Biologia & CESAM, Universidade de Aveiro, Aveiro, Portugal
| | - Bruno B. Castro
- Departamento de Biologia & CESAM, Universidade de Aveiro, Aveiro, Portugal
- * E-mail:
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Lee JE, Buckley HL, Etienne RS, Lear G. Both species sorting and neutral processes drive assembly of bacterial communities in aquatic microcosms. FEMS Microbiol Ecol 2013; 86:288-302. [DOI: 10.1111/1574-6941.12161] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 06/03/2013] [Accepted: 06/04/2013] [Indexed: 12/21/2022] Open
Affiliation(s)
- Jack E. Lee
- Department of Soil and Physical Sciences; Lincoln University; Lincoln; New Zealand
| | | | - Rampal S. Etienne
- Community and Conservation Ecology Group; University of Groningen; Groningen; The Netherlands
| | - Gavin Lear
- School of Biological Sciences; The University of Auckland; Auckland; New Zealand
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