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Arias-Real R, Delgado-Baquerizo M, Sabater S, Gutiérrez-Cánovas C, Valencia E, Aragón G, Cantón Y, Datry T, Giordani P, Medina NG, de Los Ríos A, Romaní AM, Weber B, Hurtado P. Unfolding the dynamics of ecosystems undergoing alternating wet-dry transitional states. Ecol Lett 2024; 27:e14488. [PMID: 39092560 DOI: 10.1111/ele.14488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 07/01/2024] [Accepted: 07/08/2024] [Indexed: 08/04/2024]
Abstract
A significant fraction of Earth's ecosystems undergoes periodic wet-dry alternating transitional states. These globally distributed water-driven transitional ecosystems, such as intermittent rivers and coastal shorelines, have traditionally been studied as two distinct entities, whereas they constitute a single, interconnected meta-ecosystem. This has resulted in a poor conceptual and empirical understanding of water-driven transitional ecosystems. Here, we develop a conceptual framework that places the temporal availability of water as the core driver of biodiversity and functional patterns of transitional ecosystems at the global scale. Biological covers (e.g., aquatic biofilms and biocrusts) serve as an excellent model system thriving in both aquatic and terrestrial states, where their succession underscores the intricate interplay between these two states. The duration, frequency, and rate of change of wet-dry cycles impose distinct plausible scenarios where different types of biological covers can occur depending on their desiccation/hydration resistance traits. This implies that the distinct eco-evolutionary potential of biological covers, represented by their trait profiles, would support different functions while maintaining similar multifunctionality levels. By embracing multiple alternating transitional states as interconnected entities, our approach can help to better understand and manage global change impacts on biodiversity and multifunctionality in water-driven transitional ecosystems, while providing new avenues for interdisciplinary studies.
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Affiliation(s)
- Rebeca Arias-Real
- Museo Nacional de Ciencias Naturales, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Manuel Delgado-Baquerizo
- Laboratorio de Biodiversidad y Funcionamiento Ecosistémico. Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Sevilla, Spain
| | - Sergi Sabater
- Catalan Institute of Water Research (ICRA), Girona, Spain
- Institute of Aquatic Ecology, University of Girona-Montilivi Campus, Girona, Spain
| | - Cayetano Gutiérrez-Cánovas
- Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain
- Instituto de Investigación en Cambio Global (IICG-URJC), Universidad Rey Juan Carlos, Móstoles, Spain
| | - Enrique Valencia
- Department of Biodiversity, Ecology and Evolution, Faculty of Biology, Universidad Complutense de Madrid, Madrid, Spain
| | - Gregorio Aragón
- Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain
- Instituto de Investigación en Cambio Global (IICG-URJC), Universidad Rey Juan Carlos, Móstoles, Spain
| | - Yolanda Cantón
- Agronomy Department, University of Almería, Almería, Spain
- Research Centre for Scientific Collections from the University of Almería (CECOUAL), Almería, Spain
| | - Thibault Datry
- INRAE, UR RiverLy, Centre de Lyon-Villeurbanne, Villeurbanne, France
| | | | - Nagore G Medina
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Investigación en Biodiversidad y Cambio Global (CIBC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Asunción de Los Ríos
- Museo Nacional de Ciencias Naturales, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Anna M Romaní
- GRECO, Institute of Aquatic Ecology, University of Girona, Girona, Spain
| | - Bettina Weber
- Division of Plant Sciences, Institute for Biology, University of Graz, Graz, Austria
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Pilar Hurtado
- Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain
- DIFAR, University of Genoa, Genoa, Italy
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2
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Gruppuso L, Receveur JP, Fenoglio S, Bona F, Benbow ME. Hidden Decomposers: the Role of Bacteria and Fungi in Recently Intermittent Alpine Streams Heterotrophic Pathways. MICROBIAL ECOLOGY 2023; 86:1499-1512. [PMID: 36646914 PMCID: PMC10497695 DOI: 10.1007/s00248-023-02169-y] [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: 06/20/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
The frequency of flow intermittency and drying events in Alpine rivers is expected to increase due to climate change. These events can have significant consequences for stream ecological communities, though the effects of reduced flow conditions on microbial communities of decomposing allochthonous leaf material require additional research. In this study, we investigated the bacterial and fungal communities associated with the decomposition of two common species of leaf litter, chestnut (Castanea sativa), and oak (Quercus robur). A sampling of experimentally placed leaf bags occurred over six collection dates (up to 126 days after placement) at seven stream sites in the Western Italian Alps with historically different flow conditions. Leaf-associated bacterial and fungal communities were identified using amplicon-based, high-throughput sequencing. Chestnut and oak leaf material harbored distinct bacterial and fungal communities, with a number of taxonomic groups differing in abundance, though bacterial community structure converged later in decomposition. Historical flow conditions (intermittent vs perennial rivers) and observed conditions (normal flow, low flow, ongoing drying event) had weaker effects on bacterial and fungal communities compared to leaf type and collection date (i.e., length of decomposition). Our findings highlight the importance of leaf characteristics (e.g., C:N ratios, recalcitrance) to the in-stream conditioning of leaf litter and a need for additional investigations of drying events in Alpine streams. This study provides new information on the microbial role in leaf litter decomposition with expected flow changes associated with a global change scenario.
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Affiliation(s)
- L Gruppuso
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123, Turin, Italy.
- Centro per lo Studio dei Fiumi Alpini (ALPSTREAM - Alpine Stream Research Center), Ostana, (CN), Italy.
| | - J P Receveur
- Institute for Genome Sciences, University of Maryland, Baltimore, MD, USA
| | - S Fenoglio
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123, Turin, Italy
- Centro per lo Studio dei Fiumi Alpini (ALPSTREAM - Alpine Stream Research Center), Ostana, (CN), Italy
| | - F Bona
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123, Turin, Italy
- Centro per lo Studio dei Fiumi Alpini (ALPSTREAM - Alpine Stream Research Center), Ostana, (CN), Italy
| | - M E Benbow
- Department of Entomology, Michigan State University, East Lansing, MI, USA
- Department of Osteopathic Medical Specialties, Michigan State University, East Lansing, MI, USA
- Ecology, Evolution and Behavior Program, Michigan State University, East Lansing, MI, USA
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3
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Bertrans-Tubau L, Menard Y, Batisson I, Creusot N, Mazzella N, Millan-Navarro D, Moreira A, Morin S, Ponsá S, Abril M, Proia L, Romaní AM, Artigas J. Dissipation of pesticides by stream biofilms is influenced by hydrological histories. FEMS Microbiol Ecol 2023; 99:fiad083. [PMID: 37480243 DOI: 10.1093/femsec/fiad083] [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] [Received: 05/31/2023] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 07/23/2023] Open
Abstract
To evaluate the effects of hydrological variability on pesticide dissipation capacity by stream biofilms, we conducted a microcosm study. We exposed biofilms to short and frequent droughts (daily frequency), long and less frequent droughts (weekly frequency) and permanently immersed controls, prior to test their capacities to dissipate a cocktail of pesticides composed of tebuconazole, terbuthylazine, imidacloprid, glyphosate and its metabolite aminomethylphosphonic acid. A range of structural and functional descriptors of biofilms (algal and bacterial biomass, extracellular polymeric matrix (EPS) concentration, microbial respiration, phosphorus uptake and community-level physiological profiles) were measured to assess drought effects. In addition, various parameters were measured to characterise the dynamics of pesticide dissipation by biofilms in the different hydrological treatments (% dissipation, peak asymmetry, bioconcentration factor, among others). Results showed higher pesticide dissipation rates in biofilms exposed to short and frequent droughts, despite of their lower biomass and EPS concentration, compared to biofilms in immersed controls or exposed to long and less frequent droughts. High accumulation of hydrophobic pesticides (tebuconazole and terbuthylazine) was measured in biofilms despite the short exposure time (few minutes) in our open-flow microcosm approach. This research demonstrated the stream biofilms capacity to adsorb hydrophobic pesticides even in stressed drought environments.
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Affiliation(s)
- Lluís Bertrans-Tubau
- BETA Technological Centre- University of Vic-Central University of Catalunya (BETA-UVic-UCC), Carretera de Roda 70, 08500 Vic, Barcelona, Spain
| | - Yoann Menard
- CNRS, Laboratoire Microorganismes: Génome et Environnement (LMGE), Université Clermont Auvergne, Campus Universitaire des Cézeaux, 1 Impasse Amélie Murat. F-63000 Clermont-Ferrand, France
| | - Isabelle Batisson
- CNRS, Laboratoire Microorganismes: Génome et Environnement (LMGE), Université Clermont Auvergne, Campus Universitaire des Cézeaux, 1 Impasse Amélie Murat. F-63000 Clermont-Ferrand, France
| | | | | | | | | | - Soizic Morin
- INRAE, UR EABX, 50 avenue de Verdun, F-33612 Cestas, France
| | - Sergio Ponsá
- BETA Technological Centre- University of Vic-Central University of Catalunya (BETA-UVic-UCC), Carretera de Roda 70, 08500 Vic, Barcelona, Spain
| | - Meritxell Abril
- BETA Technological Centre- University of Vic-Central University of Catalunya (BETA-UVic-UCC), Carretera de Roda 70, 08500 Vic, Barcelona, Spain
| | - Lorenzo Proia
- BETA Technological Centre- University of Vic-Central University of Catalunya (BETA-UVic-UCC), Carretera de Roda 70, 08500 Vic, Barcelona, Spain
| | - Anna M Romaní
- Institute of Aquatic Ecology, University of Girona, Campus Montilivi, 17005 Girona, Spain
| | - Joan Artigas
- CNRS, Laboratoire Microorganismes: Génome et Environnement (LMGE), Université Clermont Auvergne, Campus Universitaire des Cézeaux, 1 Impasse Amélie Murat. F-63000 Clermont-Ferrand, France
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Rožman M, Lekunberri I, Grgić I, Borrego CM, Petrović M. Effects of combining flow intermittency and exposure to emerging contaminants on the composition and metabolic response of streambed biofilm bacterial communities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 877:162818. [PMID: 36914121 DOI: 10.1016/j.scitotenv.2023.162818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 02/20/2023] [Accepted: 03/08/2023] [Indexed: 05/06/2023]
Abstract
Freshwater ecosystems are characterised by the co-occurrence of stressors that simultaneously affect the biota. Among these, flow intermittency and chemical pollution severely impair the diversity and functioning of streambed bacterial communities. Using an artificial streams mesocosm facility, this study examined how desiccation and pollution caused by emerging contaminants affect the composition of stream biofilm bacterial communities, their metabolic profiles, and interactions with their environment. Through an integrative analysis of the composition of biofilm communities, characterization of their metabolome and composition of the dissolved organic matter, we found strong genotype-to-phenotype interconnections. The strongest correlation was found between the composition and metabolism of the bacterial community, both of which were influenced by incubation time and desiccation. Unexpectedly, no effect of the emerging contaminants was observed, which was due to the low concentration of the emerging contaminants and the dominant impact of desiccation. However, biofilm bacterial communities modified the chemical composition of their environment under the effect of pollution. Considering the tentatively identified classes of metabolites, we hypothesised that the biofilm response to desiccation was mainly intracellular while the response to chemical pollution was extracellular. The present study demonstrates that metabolite and dissolved organic matter profiling may be effectively integrated with compositional analysis of stream biofilm communities to yield a more complete picture of changes in response to stressors.
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Affiliation(s)
- Marko Rožman
- Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia; Catalan Institute for Water Research (ICRA), Emili Grahit 101, 17003 Girona, Spain.
| | - Itziar Lekunberri
- Catalan Institute for Water Research (ICRA), Emili Grahit 101, 17003 Girona, Spain
| | - Ivana Grgić
- Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Carles M Borrego
- Catalan Institute for Water Research (ICRA), Emili Grahit 101, 17003 Girona, Spain; Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, E-17001 Girona, Spain
| | - Mira Petrović
- Catalan Institute for Water Research (ICRA), Emili Grahit 101, 17003 Girona, Spain; Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys 23, 08010 Barcelona, Spain
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5
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Drying Shapes Aquatic Fungal Community Assembly by Reducing Functional Diversity. DIVERSITY 2023. [DOI: 10.3390/d15020289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Aquatic fungi are highly diverse organisms that play a critical role in global biogeochemical cycles. Yet it remains unclear which assembly processes determine their co-occurrence and assembly patterns over gradients of drying intensity, which is a common stressor in fluvial networks. Although aquatic fungi possess drying-specific adaptations, little is known about how functional similarity influences co-occurrence probability and which functional traits are sorted by drying. Using field data from 15 streams, we investigated how co-occurrence patterns and assembly processes responded to drying intensity. To do so, we determined fungal co-occurrence patterns, functional traits that best explain species co-occurrence likelihood, and community assembly mechanisms explaining changes in functional diversity over the drying gradient. Our results identified 24 species pairs with positive co-occurrence probabilities and 16 species pairs with negative associations. The co-occurrence probability was correlated with species differences in conidia shape and fungal endophytic capacity. Functional diversity reduction over the drying gradient is generally associated with non-random abiotic filtering. However, the assembly processes changed over the drying gradient, with random assembly prevailing at low drying intensity and abiotic filtering gaining more importance as drying intensifies. Collectively, our results can help anticipate the impacts of global change on fungal communities and ecosystem functioning.
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Arias-Real R, Menéndez M, Muñoz I, Pascoal C. Drying shapes the ecological niche of aquatic fungi with implications on ecosystem functioning. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 859:160374. [PMID: 36427710 DOI: 10.1016/j.scitotenv.2022.160374] [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: 07/21/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
Fungi are among the most abundant and diverse organisms on Earth and play pivotal roles in global carbon processing, nutrient cycling and food webs. Despite their abundant and functional importance, little is known about the patterns and mechanisms governing their community composition in intermittent rivers and ephemeral streams, which are the most common fluvial ecosystems globally. Thus far, it is known that aquatic fungi have evolved various life-history strategies and functional adaptations to cope with drying. Nevertheless, some of these adaptations have a metabolic cost and trade-offs between growth, reproduction and dispersion that may affect ecosystem functioning. Thus, understanding their ecological strategies along a gradient of drying is crucial to assess how species will respond to global change and to identify meaningful taxa to maintain ecosystem functions. By combining in situ hydrological information with a niche-based approach, we analysed the role of drying in explaining the spatial segregation of fungal species, and we determined their specialization and affinity over a gradient of drying. In addition, we estimated whether species niches are good predictors of two key ecosystem processes: organic matter decomposition and fungal biomass accrual. Overall, we found that annual drying duration and frequency were the most influential variables upon species niche differentiation across the 15 studied streams. Our cluster analysis identified four drying niche-based groups with contrasting distributions and responses over the drying gradient: drying-sensitive, partly tolerant to drying, generalist, and drying-resistant specialist. In addition, we found that species belonging to the drying specialist group showed a weak contribution to both ecosystem processes, suggesting trade-offs between drying resistance strategies and the energy invested in growth. Taken together, our results suggest that increased water scarcity may jeopardise the capacity of aquatic fungi to guarantee ecosystem functioning and to maintain biogeochemical cycles despite their ability to cope with drying.
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Affiliation(s)
- Rebeca Arias-Real
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal; Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, Universitat de Barcelona, Av. Diagonal, 643, 08028 Barcelona, Spain.
| | - Margarita Menéndez
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, Universitat de Barcelona, Av. Diagonal, 643, 08028 Barcelona, Spain
| | - Isabel Muñoz
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, Universitat de Barcelona, Av. Diagonal, 643, 08028 Barcelona, Spain
| | - Cláudia Pascoal
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
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7
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Miao L, Li C, Adyel TM, Huang W, Wu J, Yu Y, Hou J. Effects of the Desiccation Duration on the Dynamic Responses of Biofilm Metabolic Activities to Rewetting. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:1828-1836. [PMID: 36637413 DOI: 10.1021/acs.est.2c07410] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Global climate changes have increased the duration and frequency of river flow interruption, affecting the physical and community structure of benthic biofilms. However, the dynamic responses of biofilm metabolism during the dry-wet transition remain poorly understood. Herein, the dynamic changes in biofilm metabolic activities were investigated through mesocosm experiments under short-term (25 day) and long-term drought (90 day), followed by a 20 day rewetting. The biofilm ecosystem metabolism, as measured by gross primary production and community respiration, was significantly inhibited and turned heterotrophic during the desiccation phase and then recovered, becoming autotrophic during the rewetting period regardless of the desiccation periods due to the high resilience of the autotrophic community. However, long-term drought decreased the recovery rate of the ecosystem metabolism and also caused irreparable damage to the biofilm carbon metabolism, measured using Biolog Eco Plates. Specifically, the recovery of the total carbon metabolic activity is related to the specific carbon source utilized by biofilm microorganisms, such as polymers, carbohydrates, and carboxylic acids. However, the divergent changes of amino acids caused the failure of the total carbon metabolism in long-term drought treatments to recover to the control level even after 20 days of rewetting. This research provides direct evidence that the increased duration of non-flow periods affects biofilm-mediated carbon biogeochemical processes.
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Affiliation(s)
- Lingzhan Miao
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Chaoran Li
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Tanveer M Adyel
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Melbourne, Victoria 3125, Australia
| | - Wei Huang
- China Institute of Water Resources and Hydropower Research, Beijing 100038, People's Republic of China
| | - Jun Wu
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China
| | - Yue Yu
- Department of Civil, Environmental, and Geomatic Engineering, ETH Zürich, Zürich 8092, Switzerland
| | - Jun Hou
- Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, People's Republic of China
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Granados V, Arias-Real R, Gutiérrez-Cánovas C, Obrador B, Butturini A. Multiple drying aspects shape dissolved organic matter composition in intermittent streams. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 852:158376. [PMID: 36049684 DOI: 10.1016/j.scitotenv.2022.158376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
Water availability is a fundamental driver of biogeochemical processing in highly dynamic ecosystems such as intermittent rivers and ephemeral streams (IRES), which are recognized as the most common fluvial ecosystem globally. Because of their global extent, IRES have a remarkable contribution to organic matter processing, which is expected to intensify as climate change and water extraction expand IRES extension. Nevertheless, the effect of the complexity of the drying process on river biogeochemistry remains unclear. This study investigated how drying aspects affect the dissolved organic carbon (DOC) concentration and composition in 35 streams along a wide flow-intermittence gradient in the NE Iberian Peninsula. To do that, four drying aspects: annual drying duration, annual frequency, duration of the last drying event, and time since the last drying event were characterized. Results showed that DOC concentration and the contribution of humic-like compounds were positively associated with intensifying drying conditions. In addition, protein-like compounds decreased over the drying gradient. More specifically, changes in DOC concentration were driven mainly by annual drying duration, whereas annual drying frequency and the duration of the last drying event jointly explained dissolved organic matter composition. These results suggest that the quantity and composition of dissolved organic matter in streams respond differently to the temporal aspects of the drying process. Our study can help to better anticipate changes in organic matter in the context of climate change.
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Affiliation(s)
- Verónica Granados
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Rebeca Arias-Real
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, Barcelona, Spain; Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal; Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
| | - Cayetano Gutiérrez-Cánovas
- Biological Invasions Group, Department of Integrative Ecology, Doñana Biological Station (EBD-CSIC), Av. Américo Vespucio, 26, Isla de la Cartuja, 41092 Seville, Spain
| | - Biel Obrador
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Andrea Butturini
- Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, Barcelona, Spain
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Abstract
AbstractInvestigating the influence of biodiversity on ecosystem functioning over environmental gradients is needed to anticipate ecosystem responses to global change. However, our understanding of the functional role of freshwater biodiversity, especially for microbes, is mainly based on manipulative experiments, where biodiversity and environmental variability are minimized. Here, we combined observational and manipulative experiments to analyse how fungal biodiversity responds to and mediates the impacts of drying on two key ecosystem processes: organic matter decomposition and fungal biomass accrual. Our observational data set consists of fungal biodiversity and ecosystem processes from 15 streams spanning a natural gradient of flow intermittence. Our manipulative design evaluates the responses of ecosystem processes to two fungal richness levels crossed with three levels of drying. For the observational experiment, we found that increasing the duration of drying reduced fungal species richness and caused compositional changes. Changes in species composition were driven by species turnover, suggesting resistance mechanisms to cope with drying. We also found that fungal richness had a positive effect on organic matter decomposition and fungal biomass accrual. Positive effects of fungal biodiversity were consistent when controlling for the effects of drying duration on richness by means of structural equation modelling. In addition, our results for the manipulative experiment showed that the positive effects of higher richness on both ecosystem processes were evident even when exposed to short or long simulated drying. Overall, our study suggests that maintaining high levels of biodiversity is crucial for maintaining functional freshwater ecosystems in response to ongoing and future environmental changes.
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