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Gomez EJ, Delgado JA, Gonzalez JM. Influence of water availability and temperature on estimates of microbial extracellular enzyme activity. PeerJ 2021; 9:e10994. [PMID: 33717705 PMCID: PMC7936561 DOI: 10.7717/peerj.10994] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/01/2021] [Indexed: 12/28/2022] Open
Abstract
Soils are highly heterogeneous and support highly diverse microbial communities. Microbial extracellular enzymes breakdown complex polymers into small assimilable molecules representing the limiting step of soil organic matter mineralization. This process occurs on to soil particles although currently it is typically estimated in laboratory aqueous solutions. Herein, estimates of microbial extracellular enzyme activity were obtained over a broad range of temperatures and water availabilities frequently observed at soil upper layers. A Pseudomonas strain presented optimum extracellular enzyme activities at high water activity whereas a desiccation resistant bacterium (Deinococcus) and a soil thermophilic isolate (Parageobacillus) showed optimum extracellular enzyme activity under dried (i.e., water activities ranging 0.5–0.8) rather that wet conditions. Different unamended soils presented a distinctive response of extracellular enzyme activity as a function of temperature and water availability. This study presents a procedure to obtain realistic estimates of microbial extracellular enzyme activity under natural soil conditions of extreme water availability and temperature. Improving estimates of microbial extracellular enzyme activity contribute to better understand the role of microorganisms in soils.
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Affiliation(s)
- Enrique J Gomez
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, IRNAS-CSIC, Sevilla, Spain
| | - Jose A Delgado
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, IRNAS-CSIC, Sevilla, Spain
| | - Juan M Gonzalez
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, IRNAS-CSIC, Sevilla, Spain
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Ruiz-González C, Rodellas V, Garcia-Orellana J. The microbial dimension of submarine groundwater discharge: current challenges and future directions. FEMS Microbiol Rev 2021; 45:6128669. [PMID: 33538813 PMCID: PMC8498565 DOI: 10.1093/femsre/fuab010] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 01/28/2021] [Indexed: 12/22/2022] Open
Abstract
Despite the relevance of submarine groundwater discharge (SGD) for ocean biogeochemistry, the microbial dimension of SGD remains poorly understood. SGD can influence marine microbial communities through supplying chemical compounds and microorganisms, and in turn, microbes at the land–ocean transition zone determine the chemistry of the groundwater reaching the ocean. However, compared with inland groundwater, little is known about microbial communities in coastal aquifers. Here, we review the state of the art of the microbial dimension of SGD, with emphasis on prokaryotes, and identify current challenges and future directions. Main challenges include improving the diversity description of groundwater microbiota, characterized by ultrasmall, inactive and novel taxa, and by high ratios of sediment-attached versus free-living cells. Studies should explore microbial dynamics and their role in chemical cycles in coastal aquifers, the bidirectional dispersal of groundwater and seawater microorganisms, and marine bacterioplankton responses to SGD. This will require not only combining sequencing methods, visualization and linking taxonomy to activity but also considering the entire groundwater–marine continuum. Interactions between traditionally independent disciplines (e.g. hydrogeology, microbial ecology) are needed to frame the study of terrestrial and aquatic microorganisms beyond the limits of their presumed habitats, and to foster our understanding of SGD processes and their influence in coastal biogeochemical cycles.
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Affiliation(s)
- Clara Ruiz-González
- Institut de Ciències del Mar (ICM-CSIC). Passeig Marítim de la Barceloneta 37-49, E08003 Barcelona, Spain
| | - Valentí Rodellas
- Institut de Ciència i Tecnologia Ambientals (ICTA-UAB), Universitat Autònoma de Barcelona, E08193 Bellaterra, Spain
| | - Jordi Garcia-Orellana
- Institut de Ciència i Tecnologia Ambientals (ICTA-UAB), Universitat Autònoma de Barcelona, E08193 Bellaterra, Spain.,Departament de Física, Universitat Autònoma de Barcelona, E08193 Bellaterra, Spain
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3
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Eswaran R, Khandeparker L. Seasonal variation in β-glucosidase-producing culturable bacterial diversity in a monsoon-influenced tropical estuary. ENVIRONMENTAL MONITORING AND ASSESSMENT 2019; 191:662. [PMID: 31650269 DOI: 10.1007/s10661-019-7818-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 09/11/2019] [Indexed: 06/10/2023]
Abstract
The episodic monsoon condition in a tropical estuarine environment inputs high allochthonous materials that are rich in carbohydrates and are mainly broken down by enzymatic hydrolysis thus alter both organic matter and microbial community composition of an estuary. β-Glucosidases are one of the enzymes mediating the degradation of carbohydrates and are majorly produced by heterotrophic bacteria. The present study elucidated β-glucosidase-producing culturable bacterial diversity and measured their activity during non-monsoon and monsoon seasons in Zuari estuary. The results revealed that both bacterial abundance and β-glucosidase activity decreased significantly from non-monsoon to monsoon, whereas phylogenetic diversity increased. Majority of β-glucosidase producers during non-monsoon belonged to the members of Bacillales (53%), Pseudomonadales (26%), and Vibrionales (11%) which shifted to the members of Enterobacteriales (51%), Bacillales (14%), Alteromonadales (12%), Aeromonadales (9%), Xanthomonadales (7%), Pseudomonadales (5%), and Flavobacteriales (2%) during the monsoon. The shift in bacterial community structure points out the occurrence of different allochthonous forms with carbohydrate-metabolizing ability during the monsoon, and their relevance in ecology and health of this estuary can be elucidated by studying their functional diversity and is a step ahead.
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Affiliation(s)
- Ranjith Eswaran
- CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, India
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Smith HJ, Zelaya AJ, De León KB, Chakraborty R, Elias DA, Hazen TC, Arkin AP, Cunningham AB, Fields MW. Impact of hydrologic boundaries on microbial planktonic and biofilm communities in shallow terrestrial subsurface environments. FEMS Microbiol Ecol 2018; 94:5107865. [PMID: 30265315 PMCID: PMC6192502 DOI: 10.1093/femsec/fiy191] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/26/2018] [Indexed: 12/12/2022] Open
Abstract
Subsurface environments contain a large proportion of planetary microbial biomass and harbor diverse communities responsible for mediating biogeochemical cycles important to groundwater used by human society for consumption, irrigation, agriculture and industry. Within the saturated zone, capillary fringe and vadose zones, microorganisms can reside in two distinct phases (planktonic or biofilm), and significant differences in community composition, structure and activity between free-living and attached communities are commonly accepted. However, largely due to sampling constraints and the challenges of working with solid substrata, the contribution of each phase to subsurface processes is largely unresolved. Here, we synthesize current information on the diversity and activity of shallow freshwater subsurface habitats, discuss the challenges associated with sampling planktonic and biofilm communities across spatial, temporal and geological gradients, and discuss how biofilms may be constrained within shallow terrestrial subsurface aquifers. We suggest that merging traditional activity measurements and sequencing/-omics technologies with hydrological parameters important to sediment biofilm assembly and stability will help delineate key system parameters. Ultimately, integration will enhance our understanding of shallow subsurface ecophysiology in terms of bulk-flow through porous media and distinguish the respective activities of sessile microbial communities from more transient planktonic communities to ecosystem service and maintenance.
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Affiliation(s)
- H J Smith
- Center for Biofilm Engineering, Montana State University, Bozeman, MT
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - A J Zelaya
- Center for Biofilm Engineering, Montana State University, Bozeman, MT
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - K B De León
- Department of Biochemistry, University of Missouri, Columbia, MO
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - R Chakraborty
- Climate and Ecosystems Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - D A Elias
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - T C Hazen
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - A P Arkin
- Department of Bioengineering, Lawrence Berkeley National Laboratory, Berkeley, CA
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - A B Cunningham
- Center for Biofilm Engineering, Montana State University, Bozeman, MT
- Department of Civil Engineering, Montana State University, Montana State University, Bozeman, MT
| | - M W Fields
- Center for Biofilm Engineering, Montana State University, Bozeman, MT
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
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Luo L, Meng H, Gu JD. Microbial extracellular enzymes in biogeochemical cycling of ecosystems. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 197:539-549. [PMID: 28419976 DOI: 10.1016/j.jenvman.2017.04.023] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 03/23/2017] [Accepted: 04/08/2017] [Indexed: 06/07/2023]
Abstract
Extracellular enzymes, primarily produced by microorganisms, affect ecosystem processes because of their essential roles in degradation, transformation and mineralization of organic matter. Extracellular enzymes involved in the cycling of carbon (C), nitrogen (N) and phosphorus (P) have been widely investigated in many different ecosystems, and several enzymes have been recognized as key components in regulating C storage and nutrient cycling. In this review, it was the first time to summarize the specific extracellular enzymes related to C storage and nutrient cycling for better understanding the important role of microbial extracellular enzymes in biogeochemical cycling of ecosystems. Subsequently, ecoenzymatic stoichiometry - the relative ratio of extracellular enzyme, has been reviewed and further provided a new perspective for understanding biogeochemical cycling of ecosystems. Finally, the new insights of using microbial extracellular enzyme in indicating biogeochemical cycling and then protecting ecosystems have been suggested.
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Affiliation(s)
- Ling Luo
- College of Environmental Sciences, Sichuan Agricultural University, Huimin Road, 611130 Chengdu, P.R. China; Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region, P.R. China.
| | - Han Meng
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region, P.R. China
| | - Ji-Dong Gu
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region, P.R. China.
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Luo L, Gu JD. Alteration of extracellular enzyme activity and microbial abundance by biochar addition: Implication for carbon sequestration in subtropical mangrove sediment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2016; 182:29-36. [PMID: 27454094 DOI: 10.1016/j.jenvman.2016.07.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 07/06/2016] [Accepted: 07/14/2016] [Indexed: 06/06/2023]
Abstract
Biochar has attracted more and more attention due to its essential role in adsorbing pollutants, improving soil fertility, and modifying greenhouse gas emission. However, the influences of biochar on extracellular enzyme activity and microbial abundance are still lack and debatable. Currently, there is no information about the impact of biochar on the function of mangrove ecosystems. Therefore, we explored the effects of biochar on extracellular enzyme activity and microbial abundance in subtropical mangrove sediment, and further estimated the contribution of biochar to C sequestration. In this study, sediments were amended with 0 (control), 0.5, 1.0 and 2.0% of biochar and incubated at 25 °C for 90 days. After incubation, enzyme activities, microbial abundance and the increased percentage of sediment organic C content were determined. Both increase (phenol oxidase and β-glucosidase) and decrease (peroxidase, N-acetyl-glucosaminidase and acid phosphatase) of enzyme activities were observed in biochar treatments, but only peroxidase activity showed statistical significance (at least p < 0.01) compared to the control. Moreover, the activities of all enzymes tested were significantly related to the content of biochar addition (at least p < 0.05). On the other hand, bacterial and fungal abundance in biochar treatments were remarkably lower than control (p < 0.001), and the significantly negative relationship (p < 0.05) between bacterial abundance and the content of biochar was found. Additionally, the increased percentage of organic C gradually increased with biochar addition rate, which provided evidence for applying biochar to mitigate climate change. Given the importance of microorganisms and enzyme activities in sediment organic matter decomposition, the increased C sequestration might be explained by the large decrease of microbial abundance and enzyme activity after biochar intervention.
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Affiliation(s)
- Ling Luo
- College of Environmental Sciences, Sichuan Agricultural University, Huimin Road, Chengdu, Sichuan Province, People's Republic of China; Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China.
| | - Ji-Dong Gu
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China.
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Freimann R, Bürgmann H, Findlay SEG, Robinson CT. Hydrologic linkages drive spatial structuring of bacterial assemblages and functioning in alpine floodplains. Front Microbiol 2015; 6:1221. [PMID: 26579113 PMCID: PMC4630579 DOI: 10.3389/fmicb.2015.01221] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 10/19/2015] [Indexed: 11/13/2022] Open
Abstract
Microbial community assembly and microbial functions are affected by a number of different but coupled drivers such as local habitat characteristics, dispersal rates, and species interactions. In groundwater systems, hydrological flow can introduce spatial structure and directional dependencies among these drivers. We examined the importance of hydrology in structuring bacterial communities and their function within two alpine floodplains during different hydrological states. Piezometers were installed in stream sediments and surrounding riparian zones to assess hydrological flows and also were used as incubation chambers to examine bacterial community structures and enzymatic functions along hydrological flow paths. Spatial eigenvector models in conjunction with models based on physico-chemical groundwater characteristics were used to evaluate the importance of hydrologically-driven processes influencing bacterial assemblages and their enzymatic activities. Our results suggest a strong influence (up to 40% explained variation) of hydrological connectivity on enzymatic activities. The effect of hydrology on bacterial community structure was considerably less strong, suggesting that assemblages demonstrate large functional plasticity/redundancy. Effect size varied between hydrological periods but flow-related mechanisms always had the most power in explaining both bacterial structure and functioning. Changes in hydrology should be considered in models predicting ecosystem functioning and integrated into ecosystem management strategies for floodplains.
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Affiliation(s)
- Remo Freimann
- Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology ETH Zurich, Dübendorf, Switzerland ; Institute of Integrative Biology ETH Zurich, Zürich, Switzerland ; Department of Biology, Institute of Molecular Health Sciences, Epigenetic Regulation and Cell Identity Control ETH Zurich, Zürich, Switzerland
| | - Helmut Bürgmann
- Department of Surface Waters - Research and Management, Eawag: Swiss Federal Institute of Aquatic Science and Technology ETH Zurich, Kastanienbaum, Switzerland
| | | | - Christopher T Robinson
- Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology ETH Zurich, Dübendorf, Switzerland ; Institute of Integrative Biology ETH Zurich, Zürich, Switzerland
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Qasemian L, Guiral D, Farnet AM. How do microlocal environmental variations affect microbial activities of a Pinus halepensis litter in a Mediterranean coastal area? THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 496:198-205. [PMID: 25089683 DOI: 10.1016/j.scitotenv.2014.07.054] [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: 01/10/2014] [Revised: 07/07/2014] [Accepted: 07/07/2014] [Indexed: 06/03/2023]
Abstract
Mediterranean coastal ecosystems suffer many different types of natural and anthropogenic environmental pressure. Microbial communities, major conductors of organic matter decomposition are also subject to these environmental constraints. In this study, our aim was to understand how microbial activities vary at a small spatio-temporal scale in a Mediterranean coastal environment. Microbial activities were monitored in a Pinus halepensis litter collected from two areas, one close to (10 m) and one far from (300 m) the French Mediterranean coast. Litters were transferred from one area to the other using litterbags and studied via different microbial indicators after 2, 5 and 13 months. Microbial Basal Respiration, qCO₂, certain enzyme activities (laccase, cellulase, β-glucosidase and acid phosphatase) and functional diversity via Biolog microplates were assayed in litterbags left in the area of origin as well as in litterbags transferred from one area to the other. Results highlight that microbial activities differ significantly in this short spatial scale over time. The influence of microlocal conditions more intensified for litters situated close to the sea, especially during summer seems to have a stressful effect on microbial communities, leading to less efficient functional activities. However, microbial activities were more strongly influenced by temporal variations linked to seasonality than by location.
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Affiliation(s)
- Leila Qasemian
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Aix-Marseille Université, UMR CNRS, IRD, Avignon Université, Faculté de St-Jérôme, F-13397 Marseille Cedex 20, France
| | - Daniel Guiral
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Aix-Marseille Université, UMR CNRS, IRD, Avignon Université, Faculté de St-Jérôme, F-13397 Marseille Cedex 20, France
| | - Anne-Marie Farnet
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Aix-Marseille Université, UMR CNRS, IRD, Avignon Université, Faculté de St-Jérôme, F-13397 Marseille Cedex 20, France.
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