1
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Purcell AM, Dijkstra P, Hungate BA, McMillen K, Schwartz E, van Gestel N. Rapid growth rate responses of terrestrial bacteria to field warming on the Antarctic Peninsula. ISME J 2023; 17:2290-2302. [PMID: 37872274 PMCID: PMC10689830 DOI: 10.1038/s41396-023-01536-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 10/05/2023] [Accepted: 10/09/2023] [Indexed: 10/25/2023]
Abstract
Ice-free terrestrial environments of the western Antarctic Peninsula are expanding and subject to colonization by new microorganisms and plants, which control biogeochemical cycling. Measuring growth rates of microbial populations and ecosystem carbon flux is critical for understanding how terrestrial ecosystems in Antarctica will respond to future warming. We implemented a field warming experiment in early (bare soil; +2 °C) and late (peat moss-dominated; +1.2 °C) successional glacier forefield sites on the western Antarctica Peninsula. We used quantitative stable isotope probing with H218O using intact cores in situ to determine growth rate responses of bacterial taxa to short-term (1 month) warming. Warming increased the growth rates of bacterial communities at both sites, even doubling the number of taxa exhibiting significant growth at the early site. Growth responses varied among taxa. Despite that warming induced a similar response for bacterial relative growth rates overall, the warming effect on ecosystem carbon fluxes was stronger at the early successional site-likely driven by increased activity of autotrophs which switched the ecosystem from a carbon source to a carbon sink. At the late-successional site, warming caused a significant increase in growth rate of many Alphaproteobacteria, but a weaker and opposite gross ecosystem productivity response that decreased the carbon sink-indicating that the carbon flux rates were driven more strongly by the plant communities. Such changes to bacterial growth and ecosystem carbon cycling suggest that the terrestrial Antarctic Peninsula can respond fast to increases in temperature, which can have repercussions for long-term elemental cycling and carbon storage.
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Affiliation(s)
- Alicia M Purcell
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
| | - Paul Dijkstra
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Bruce A Hungate
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kelly McMillen
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Natasja van Gestel
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
- TTU Climate Center, Texas Tech University, Lubbock, TX, USA
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2
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Mikucki JA, Schuler CG, Digel I, Kowalski J, Tuttle MJ, Chua M, Davis R, Purcell AM, Ghosh D, Francke G, Feldmann M, Espe C, Heinen D, Dachwald B, Clemens J, Lyons WB, Tulaczyk S. Field-Based Planetary Protection Operations for Melt Probes: Validation of Clean Access into the Blood Falls, Antarctica, Englacial Ecosystem. Astrobiology 2023; 23:1165-1178. [PMID: 37962840 DOI: 10.1089/ast.2021.0102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. We describe the field-based cleaning of a melt probe that was used to collect brine samples from within a glacier conduit at Blood Falls, Antarctica, for geomicrobiological studies. We used a thermoelectric melting probe called the IceMole that was designed to be minimally invasive in that the logistical requirements in support of drilling operations were small and the probe could be cleaned, even in a remote field setting, so as to minimize potential contamination. In our study, the exterior bioburden on the IceMole was reduced to levels measured in most clean rooms, and below that of the ice surrounding our sampling target. Potential microbial contaminants were identified during the cleaning process; however, very few were detected in the final englacial sample collected with the IceMole and were present in extremely low abundances (∼0.063% of 16S rRNA gene amplicon sequences). This cleaning protocol can help minimize contamination when working in remote field locations, support microbiological sampling of terrestrial subglacial environments using melting probes, and help inform planetary protection challenges for Ocean World analog mission concepts.
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Affiliation(s)
- J A Mikucki
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - C G Schuler
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - I Digel
- FH Aachen - Campus Jülich, Institute of Bioengineering, Julich, Nordrhein-Westfalen, Germany
| | - J Kowalski
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - M J Tuttle
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - M Chua
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - R Davis
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - A M Purcell
- Northern Arizona University, Flagstaff, Arizona, USA
| | - D Ghosh
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - G Francke
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - M Feldmann
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - C Espe
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - D Heinen
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - B Dachwald
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - J Clemens
- University of Bremen, Bremen, Germany
| | - W B Lyons
- The Ohio State University, Byrd Polar Research Center, Columbus, Ohio, USA
| | - S Tulaczyk
- University of California Santa Cruz, Santa Cruz, California, USA
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3
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Walkup J, Dang C, Mau RL, Hayer M, Schwartz E, Stone BW, Hofmockel KS, Koch BJ, Purcell AM, Pett-Ridge J, Wang C, Hungate BA, Morrissey EM. The predictive power of phylogeny on growth rates in soil bacterial communities. ISME Commun 2023; 3:73. [PMID: 37454187 PMCID: PMC10349831 DOI: 10.1038/s43705-023-00281-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/18/2023]
Abstract
Predicting ecosystem function is critical to assess and mitigate the impacts of climate change. Quantitative predictions of microbially mediated ecosystem processes are typically uninformed by microbial biodiversity. Yet new tools allow the measurement of taxon-specific traits within natural microbial communities. There is mounting evidence of a phylogenetic signal in these traits, which may support prediction and microbiome management frameworks. We investigated phylogeny-based trait prediction using bacterial growth rates from soil communities in Arctic, boreal, temperate, and tropical ecosystems. Here we show that phylogeny predicts growth rates of soil bacteria, explaining an average of 31%, and up to 58%, of the variation within ecosystems. Despite limited overlap in community composition across these ecosystems, shared nodes in the phylogeny enabled ancestral trait reconstruction and cross-ecosystem predictions. Phylogenetic relationships could explain up to 38% (averaging 14%) of the variation in growth rates across the highly disparate ecosystems studied. Our results suggest that shared evolutionary history contributes to similarity in the relative growth rates of related bacteria in the wild, allowing phylogeny-based predictions to explain a substantial amount of the variation in taxon-specific functional traits, within and across ecosystems.
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Affiliation(s)
- Jeth Walkup
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Chansotheary Dang
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Rebecca L Mau
- Center for Ecosystem Science and Society (Ecoss), Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Michaela Hayer
- Center for Ecosystem Science and Society (Ecoss), Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society (Ecoss), Northern Arizona University, Flagstaff, AZ, 86011, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Bram W Stone
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Kirsten S Hofmockel
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Benjamin J Koch
- Center for Ecosystem Science and Society (Ecoss), Northern Arizona University, Flagstaff, AZ, 86011, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Alicia M Purcell
- Center for Ecosystem Science and Society (Ecoss), Northern Arizona University, Flagstaff, AZ, 86011, USA
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA
| | - Jennifer Pett-Ridge
- Lawrence Livermore National Laboratory, Physical and Life Science Directorate, Livermore, CA, USA
- University of California Merced, Life & Environmental Sciences Department, Merced, CA, 95343, USA
| | - Chao Wang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, LN, China
| | - Bruce A Hungate
- Center for Ecosystem Science and Society (Ecoss), Northern Arizona University, Flagstaff, AZ, 86011, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Ember M Morrissey
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA.
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4
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Stone BWG, Dijkstra P, Finley BK, Fitzpatrick R, Foley MM, Hayer M, Hofmockel KS, Koch BJ, Li J, Liu XJA, Martinez A, Mau RL, Marks J, Monsaint-Queeney V, Morrissey EM, Propster J, Pett-Ridge J, Purcell AM, Schwartz E, Hungate BA. Life history strategies among soil bacteria-dichotomy for few, continuum for many. ISME J 2023; 17:611-619. [PMID: 36732614 PMCID: PMC10030646 DOI: 10.1038/s41396-022-01354-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 02/04/2023]
Abstract
Study of life history strategies may help predict the performance of microorganisms in nature by organizing the complexity of microbial communities into groups of organisms with similar strategies. Here, we tested the extent that one common application of life history theory, the copiotroph-oligotroph framework, could predict the relative population growth rate of bacterial taxa in soils from four different ecosystems. We measured the change of in situ relative growth rate to added glucose and ammonium using both 18O-H2O and 13C quantitative stable isotope probing to test whether bacterial taxa sorted into copiotrophic and oligotrophic groups. We saw considerable overlap in nutrient responses across most bacteria regardless of phyla, with many taxa growing slowly and few taxa that grew quickly. To define plausible life history boundaries based on in situ relative growth rates, we applied Gaussian mixture models to organisms' joint 18O-13C signatures and found that across experimental replicates, few taxa could consistently be assigned as copiotrophs, despite their potential for fast growth. When life history classifications were assigned based on average relative growth rate at varying taxonomic levels, finer resolutions (e.g., genus level) were significantly more effective in capturing changes in nutrient response than broad taxonomic resolution (e.g., phylum level). Our results demonstrate the difficulty in generalizing bacterial life history strategies to broad lineages, and even to single organisms across a range of soils and experimental conditions. We conclude that there is a continued need for the direct measurement of microbial communities in soil to advance ecologically realistic frameworks.
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Affiliation(s)
- Bram W G Stone
- Earth and Biological Sciences Directorate, Pacific Northwest National Lab, Richland, WA, USA.
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.
| | - Paul Dijkstra
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Brianna K Finley
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
| | - Raina Fitzpatrick
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Megan M Foley
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Michaela Hayer
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Kirsten S Hofmockel
- Earth and Biological Sciences Directorate, Pacific Northwest National Lab, Richland, WA, USA
- Department of Agronomy, Iowa State University, Ames, IA, USA
| | - Benjamin J Koch
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Junhui Li
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- APC Microbiome Ireland and School of Microbiology, University College Cork, Cork, Ireland
| | - Xiao Jun A Liu
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Ayla Martinez
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Rebecca L Mau
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Jane Marks
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | | | - Ember M Morrissey
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, USA
| | - Jeffrey Propster
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Lab, Livermore, CA, USA
- Life and Environmental Sciences Department, University of California Merced, Merced, CA, USA
| | - Alicia M Purcell
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Bruce A Hungate
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
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5
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Purcell AM, Hayer M, Koch BJ, Mau RL, Blazewicz SJ, Dijkstra P, Mack MC, Marks JC, Morrissey EM, Pett‐Ridge J, Rubin RL, Schwartz E, van Gestel NC, Hungate BA. Decreased growth of wild soil microbes after 15 years of transplant-induced warming in a montane meadow. Glob Chang Biol 2022; 28:128-139. [PMID: 34587352 PMCID: PMC9293287 DOI: 10.1111/gcb.15911] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 09/02/2021] [Accepted: 09/09/2021] [Indexed: 05/19/2023]
Abstract
The carbon stored in soil exceeds that of plant biomass and atmospheric carbon and its stability can impact global climate. Growth of decomposer microorganisms mediates both the accrual and loss of soil carbon. Growth is sensitive to temperature and given the vast biological diversity of soil microorganisms, the response of decomposer growth rates to warming may be strongly idiosyncratic, varying among taxa, making ecosystem predictions difficult. Here, we show that 15 years of warming by transplanting plant-soil mesocosms down in elevation, strongly reduced the growth rates of soil microorganisms, measured in the field using undisturbed soil. The magnitude of the response to warming varied among microbial taxa. However, the direction of the response-reduced growth-was universal and warming explained twofold more variation than did the sum of taxonomic identity and its interaction with warming. For this ecosystem, most of the growth responses to warming could be explained without taxon-specific information, suggesting that in some cases microbial responses measured in aggregate may be adequate for climate modeling. Long-term experimental warming also reduced soil carbon content, likely a consequence of a warming-induced increase in decomposition, as warming-induced changes in plant productivity were negligible. The loss of soil carbon and decreased microbial biomass with warming may explain the reduced growth of the microbial community, more than the direct effects of temperature on growth. These findings show that direct and indirect effects of long-term warming can reduce growth rates of soil microbes, which may have important feedbacks to global warming.
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Affiliation(s)
- Alicia M. Purcell
- Department of Biological SciencesCenter for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
| | - Michaela Hayer
- Department of Biological SciencesCenter for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
| | - Benjamin J. Koch
- Department of Biological SciencesCenter for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
| | - Rebecca L. Mau
- Department of Biological SciencesCenter for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
| | - Steven J. Blazewicz
- Physical and Life Sciences DirectorateLawrence Livermore National LabLivermoreCaliforniaUSA
| | - Paul Dijkstra
- Department of Biological SciencesCenter for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
| | - Michelle C. Mack
- Department of Biological SciencesCenter for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
| | - Jane C. Marks
- Department of Biological SciencesCenter for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
| | - Ember M. Morrissey
- Division of Plant and Soil SciencesWest Virginia UniversityMorgantownWest VirginiaUSA
| | - Jennifer Pett‐Ridge
- Physical and Life Sciences DirectorateLawrence Livermore National LabLivermoreCaliforniaUSA
- Life & Environmental Sciences DepartmentUniversity of California MercedMercedCAUSA
| | - Rachel L. Rubin
- Department of Environmental SciencesMount Holyoke CollegeSouth HadleyMassachusettsUSA
| | - Egbert Schwartz
- Department of Biological SciencesCenter for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
| | - Natasja C. van Gestel
- Department of Biological Sciences & TTU Climate CenterTexas Tech UniversityLubbockTexasUSA
| | - Bruce A. Hungate
- Department of Biological SciencesCenter for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
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6
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Hungate BA, Marks JC, Power ME, Schwartz E, van Groenigen KJ, Blazewicz SJ, Chuckran P, Dijkstra P, Finley BK, Firestone MK, Foley M, Greenlon A, Hayer M, Hofmockel KS, Koch BJ, Mack MC, Mau RL, Miller SN, Morrissey EM, Propster JR, Purcell AM, Sieradzki E, Starr EP, Stone BWG, Terrer C, Pett-Ridge J. The Functional Significance of Bacterial Predators. mBio 2021; 12:e00466-21. [PMID: 33906922 PMCID: PMC8092244 DOI: 10.1128/mbio.00466-21] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 03/02/2021] [Indexed: 02/07/2023] Open
Abstract
Predation structures food webs, influences energy flow, and alters rates and pathways of nutrient cycling through ecosystems, effects that are well documented for macroscopic predators. In the microbial world, predatory bacteria are common, yet little is known about their rates of growth and roles in energy flows through microbial food webs, in part because these are difficult to quantify. Here, we show that growth and carbon uptake were higher in predatory bacteria compared to nonpredatory bacteria, a finding across 15 sites, synthesizing 82 experiments and over 100,000 taxon-specific measurements of element flow into newly synthesized bacterial DNA. Obligate predatory bacteria grew 36% faster and assimilated carbon at rates 211% higher than nonpredatory bacteria. These differences were less pronounced for facultative predators (6% higher growth rates, 17% higher carbon assimilation rates), though high growth and carbon assimilation rates were observed for some facultative predators, such as members of the genera Lysobacter and Cytophaga, both capable of gliding motility and wolf-pack hunting behavior. Added carbon substrates disproportionately stimulated growth of obligate predators, with responses 63% higher than those of nonpredators for the Bdellovibrionales and 81% higher for the Vampirovibrionales, whereas responses of facultative predators to substrate addition were no different from those of nonpredators. This finding supports the ecological theory that higher productivity increases predator control of lower trophic levels. These findings also indicate that the functional significance of bacterial predators increases with energy flow and that predatory bacteria influence element flow through microbial food webs.IMPORTANCE The word "predator" may conjure images of leopards killing and eating impala on the African savannah or of great white sharks attacking elephant seals off the coast of California. But microorganisms are also predators, including bacteria that kill and eat other bacteria. While predatory bacteria have been found in many environments, it has been challenging to document their importance in nature. This study quantified the growth of predatory and nonpredatory bacteria in soils (and one stream) by tracking isotopically labeled substrates into newly synthesized DNA. Predatory bacteria were more active than nonpredators, and obligate predators, such as Bdellovibrionales and Vampirovibrionales, increased in growth rate in response to added substrates at the base of the food chain, strong evidence of trophic control. This work provides quantitative measures of predator activity and suggests that predatory bacteria-along with protists, nematodes, and phages-are active and important in microbial food webs.
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Affiliation(s)
- Bruce A Hungate
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Jane C Marks
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Mary E Power
- Department of Integrative Biology, University of California Berkeley, Berkeley, California, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Kees Jan van Groenigen
- Department of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Steven J Blazewicz
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Peter Chuckran
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Paul Dijkstra
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Brianna K Finley
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Mary K Firestone
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA
| | - Megan Foley
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Alex Greenlon
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Michaela Hayer
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
| | - Kirsten S Hofmockel
- Pacific Northwest National Laboratory, Richland, Washington, USA
- Department of Agronomy, Iowa State University, Ames, Iowa, USA
| | - Benjamin J Koch
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Michelle C Mack
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Rebecca L Mau
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Samantha N Miller
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
| | - Ember M Morrissey
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Jeffrey R Propster
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Alicia M Purcell
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Ella Sieradzki
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA
| | - Evan P Starr
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Bram W G Stone
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
| | - César Terrer
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
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7
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Wang C, Morrissey EM, Mau RL, Hayer M, Piñeiro J, Mack MC, Marks JC, Bell SL, Miller SN, Schwartz E, Dijkstra P, Koch BJ, Stone BW, Purcell AM, Blazewicz SJ, Hofmockel KS, Pett-Ridge J, Hungate BA. The temperature sensitivity of soil: microbial biodiversity, growth, and carbon mineralization. ISME J 2021; 15:2738-2747. [PMID: 33782569 DOI: 10.1038/s41396-021-00959-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/19/2021] [Accepted: 03/04/2021] [Indexed: 11/09/2022]
Abstract
Microorganisms drive soil carbon mineralization and changes in their activity with increased temperature could feedback to climate change. Variation in microbial biodiversity and the temperature sensitivities (Q10) of individual taxa may explain differences in the Q10 of soil respiration, a possibility not previously examined due to methodological limitations. Here, we show phylogenetic and taxonomic variation in the Q10 of growth (5-35 °C) among soil bacteria from four sites, one from each of Arctic, boreal, temperate, and tropical biomes. Differences in the temperature sensitivities of taxa and the taxonomic composition of communities determined community-assembled bacterial growth Q10, which was strongly predictive of soil respiration Q10 within and across biomes. Our results suggest community-assembled traits of microbial taxa may enable enhanced prediction of carbon cycling feedbacks to climate change in ecosystems across the globe.
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Affiliation(s)
- Chao Wang
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, USA.,CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, China
| | - Ember M Morrissey
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, USA.
| | - Rebecca L Mau
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Michaela Hayer
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Juan Piñeiro
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, USA
| | - Michelle C Mack
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Jane C Marks
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Sheryl L Bell
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Samantha N Miller
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Paul Dijkstra
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Benjamin J Koch
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Bram W Stone
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Alicia M Purcell
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
| | - Steven J Blazewicz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Kirsten S Hofmockel
- Physical and Life Sciences Directorate, Lawrence Livermore National Lab, Livermore, CA, USA.,Ecology, Evolution and Organismal Biology Department, Iowa State University, Ames, IA, USA
| | - Jennifer Pett-Ridge
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Bruce A Hungate
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.,Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
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8
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Vick-Majors TJ, Mitchell AC, Achberger AM, Christner BC, Dore JE, Michaud AB, Mikucki JA, Purcell AM, Skidmore ML, Priscu JC. Physiological Ecology of Microorganisms in Subglacial Lake Whillans. Front Microbiol 2016; 7:1705. [PMID: 27833599 PMCID: PMC5081474 DOI: 10.3389/fmicb.2016.01705] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/12/2016] [Indexed: 11/13/2022] Open
Abstract
Subglacial microbial habitats are widespread in glaciated regions of our planet. Some of these environments have been isolated from the atmosphere and from sunlight for many thousands of years. Consequently, ecosystem processes must rely on energy gained from the oxidation of inorganic substrates or detrital organic matter. Subglacial Lake Whillans (SLW) is one of more than 400 subglacial lakes known to exist under the Antarctic ice sheet; however, little is known about microbial physiology and energetics in these systems. When it was sampled through its 800 m thick ice cover in 2013, the SLW water column was shallow (~2 m deep), oxygenated, and possessed sufficient concentrations of C, N, and P substrates to support microbial growth. Here, we use a combination of physiological assays and models to assess the energetics of microbial life in SLW. In general, SLW microorganisms grew slowly in this energy-limited environment. Heterotrophic cellular carbon turnover times, calculated from 3H-thymidine and 3H-leucine incorporation rates, were long (60 to 500 days) while cellular doubling times averaged 196 days. Inferred growth rates (average ~0.006 d-1) obtained from the same incubations were at least an order of magnitude lower than those measured in Antarctic surface lakes and oligotrophic areas of the ocean. Low growth efficiency (8%) indicated that heterotrophic populations in SLW partition a majority of their carbon demand to cellular maintenance rather than growth. Chemoautotrophic CO2-fixation exceeded heterotrophic organic C-demand by a factor of ~1.5. Aerobic respiratory activity associated with heterotrophic and chemoautotrophic metabolism surpassed the estimated supply of oxygen to SLW, implying that microbial activity could deplete the oxygenated waters, resulting in anoxia. We used thermodynamic calculations to examine the biogeochemical and energetic consequences of environmentally imposed switching between aerobic and anaerobic metabolisms in the SLW water column. Heterotrophic metabolisms utilizing acetate and formate as electron donors yielded less energy than chemolithotrophic metabolisms when calculated in terms of energy density, which supports experimental results that showed chemoautotrophic activity in excess of heterotrophic activity. The microbial communities of subglacial lake ecosystems provide important natural laboratories to study the physiological and biogeochemical behavior of microorganisms inhabiting cold, dark environments.
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Affiliation(s)
- Trista J Vick-Majors
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
| | - Andrew C Mitchell
- Department of Geography and Earth Sciences, Aberystwyth University Aberystwyth, UK
| | - Amanda M Achberger
- Department of Biological Sciences, Louisiana State University Baton Rouge, LA, USA
| | - Brent C Christner
- Department of Microbiology and Cell Science, University of FloridaGainesville, FL, USA; Biodiversity Institute, University of FloridaGainesville, FL, USA
| | - John E Dore
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
| | - Alexander B Michaud
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
| | - Jill A Mikucki
- Department of Microbiology, University of Tennessee Knoxville, TN, USA
| | - Alicia M Purcell
- Department of Microbiology, University of Tennessee Knoxville, TN, USA
| | - Mark L Skidmore
- Department of Earth Sciences, Montana State University Bozeman, MT, USA
| | - John C Priscu
- Department of Land Resources and Environmental Sciences, Montana State University Bozeman, MT, USA
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9
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Mikucki JA, Lee PA, Ghosh D, Purcell AM, Mitchell AC, Mankoff KD, Fisher AT, Tulaczyk S, Carter S, Siegfried MR, Fricker HA, Hodson T, Coenen J, Powell R, Scherer R, Vick-Majors T, Achberger AA, Christner BC, Tranter M. Subglacial Lake Whillans microbial biogeochemistry: a synthesis of current knowledge. Philos Trans A Math Phys Eng Sci 2016; 374:rsta.2014.0290. [PMID: 26667908 DOI: 10.1098/rsta.2014.0290] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Liquid water occurs below glaciers and ice sheets globally, enabling the existence of an array of aquatic microbial ecosystems. In Antarctica, large subglacial lakes are present beneath hundreds to thousands of metres of ice, and scientific interest in exploring these environments has escalated over the past decade. After years of planning, the first team of scientists and engineers cleanly accessed and retrieved pristine samples from a West Antarctic subglacial lake ecosystem in January 2013. This paper reviews the findings to date on Subglacial Lake Whillans and presents new supporting data on the carbon and energy metabolism of resident microbes. The analysis of water and sediments from the lake revealed a diverse microbial community composed of bacteria and archaea that are close relatives of species known to use reduced N, S or Fe and CH4 as energy sources. The water chemistry of Subglacial Lake Whillans was dominated by weathering products from silicate minerals with a minor influence from seawater. Contributions to water chemistry from microbial sulfide oxidation and carbonation reactions were supported by genomic data. Collectively, these results provide unequivocal evidence that subglacial environments in this region of West Antarctica host active microbial ecosystems that participate in subglacial biogeochemical cycling.
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Affiliation(s)
- J A Mikucki
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - P A Lee
- Hollings Marine Lab, College of Charleston, Charleston, SC 29412, USA
| | - D Ghosh
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
| | - A M Purcell
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
| | - A C Mitchell
- Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, UK
| | - K D Mankoff
- Department of Geosciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - A T Fisher
- Earth and Planetary Sciences, University of California, Santa Cruz, CA, USA
| | - S Tulaczyk
- Earth and Planetary Sciences, University of California, Santa Cruz, CA, USA
| | - S Carter
- Institute for Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA
| | - M R Siegfried
- Institute for Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA
| | - H A Fricker
- Institute for Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA
| | - T Hodson
- Department of Geology and Environmental Geosciences Northern, Illinois University, DeKalb, IL 60115, USA
| | - J Coenen
- Department of Geology and Environmental Geosciences Northern, Illinois University, DeKalb, IL 60115, USA
| | - R Powell
- Department of Geology and Environmental Geosciences Northern, Illinois University, DeKalb, IL 60115, USA
| | - R Scherer
- Department of Geology and Environmental Geosciences Northern, Illinois University, DeKalb, IL 60115, USA
| | - T Vick-Majors
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA
| | - A A Achberger
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - B C Christner
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - M Tranter
- Bristol Glaciology Centre, Geographical Sciences, University of Bristol, Bristol BS8 1SS, UK
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10
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Purcell AM, Mikucki JA, Achberger AM, Alekhina IA, Barbante C, Christner BC, Ghosh D, Michaud AB, Mitchell AC, Priscu JC, Scherer R, Skidmore ML, Vick-Majors TJ, the WISSARD Science Team. Microbial sulfur transformations in sediments from Subglacial Lake Whillans. Front Microbiol 2014; 5:594. [PMID: 25477865 PMCID: PMC4237127 DOI: 10.3389/fmicb.2014.00594] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/21/2014] [Indexed: 11/13/2022] Open
Abstract
Diverse microbial assemblages inhabit subglacial aquatic environments. While few of these environments have been sampled, data reveal that subglacial organisms gain energy for growth from reduced minerals containing nitrogen, iron, and sulfur. Here we investigate the role of microbially mediated sulfur transformations in sediments from Subglacial Lake Whillans (SLW), Antarctica, by examining key genes involved in dissimilatory sulfur oxidation and reduction. The presence of sulfur transformation genes throughout the top 34 cm of SLW sediments changes with depth. SLW surficial sediments were dominated by genes related to known sulfur-oxidizing chemoautotrophs. Sequences encoding the adenosine-5'-phosphosulfate (APS) reductase gene, involved in both dissimilatory sulfate reduction and sulfur oxidation, were present in all samples and clustered into 16 distinct operational taxonomic units. The majority of APS reductase sequences (74%) clustered with known sulfur oxidizers including those within the "Sideroxydans" and Thiobacillus genera. Reverse-acting dissimilatory sulfite reductase (rDSR) and 16S rRNA gene sequences further support dominance of "Sideroxydans" and Thiobacillus phylotypes in the top 2 cm of SLW sediments. The SLW microbial community has the genetic potential for sulfate reduction which is supported by experimentally measured low rates (1.4 pmol cm(-3)d(-1)) of biologically mediated sulfate reduction and the presence of APS reductase and DSR gene sequences related to Desulfobacteraceae and Desulfotomaculum. Our results also infer the presence of sulfur oxidation, which can be a significant energetic pathway for chemosynthetic biosynthesis in SLW sediments. The water in SLW ultimately flows into the Ross Sea where intermediates from subglacial sulfur transformations can influence the flux of solutes to the Southern Ocean.
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Affiliation(s)
- Alicia M. Purcell
- Department of Microbiology, University of TennesseeKnoxville, TN, USA
| | - Jill A. Mikucki
- Department of Microbiology, University of TennesseeKnoxville, TN, USA
| | - Amanda M. Achberger
- Department of Biological Sciences, Louisiana State UniversityBaton Rouge, LA, USA
| | - Irina A. Alekhina
- Climate and Environmental Research Laboratory, Arctic and Antarctic Research Institute, St.Petersburg, Russia
| | - Carlo Barbante
- Institute for the Dynamics of Environmental Processes – Consiglio Nazionale delle Ricerche and Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University of VeniceVenice, Italy
| | - Brent C. Christner
- Department of Biological Sciences, Louisiana State UniversityBaton Rouge, LA, USA
| | - Dhritiman Ghosh
- Department of Microbiology, University of TennesseeKnoxville, TN, USA
| | - Alexander B. Michaud
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
| | | | - John C. Priscu
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
| | - Reed Scherer
- Department of Geological and Environmental Sciences, Northern Illinois UniversityDeKalb, IL, USA
| | - Mark L. Skidmore
- Department of Earth Sciences, Montana State UniversityBozeman, MT, USA
| | - Trista J. Vick-Majors
- Department of Land Resources and Environmental Sciences, Montana State UniversityBozeman, MT, USA
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