1
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Stanish LF, Kohler TJ, Darling J, McKnight DM. Drifting along: using diatoms to track the contribution of microbial mats to particulate organic matter transport in a glacial meltwater stream in the McMurdo Dry Valleys, Antarctica. Front Microbiol 2024; 15:1352666. [PMID: 38784810 PMCID: PMC11112031 DOI: 10.3389/fmicb.2024.1352666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 04/25/2024] [Indexed: 05/25/2024] Open
Abstract
Flow pulses mobilize particulate organic matter (POM) in streams from the surrounding landscape and streambed. This POM serves as a source of energy and nutrients, as well as a means for organismal dispersal, to downstream communities. In the barren terrestrial landscape of the McMurdo Dry Valleys (MDV) of Antarctica, benthic microbial mats occupying different in-stream habitat types are the dominant POM source in the many glacier-fed streams. Many of these streams experience daily flow peaks that mobilize POM, and diatoms recovered from underlying stream sediments suggest that mat-derived diatoms in the POM are retained there through hyporheic exchange. Yet, 'how much' and 'when' different in-stream habitat types contribute to POM diatom assemblages is unknown. To quantify the contribution of different in-stream habitat types to POM diatom assemblages, we collected time-integrated POM samples over four diel experiments, which spanned a gradient of flow conditions over three summers. Diatoms from POM samples were identified, quantified, and compared with dominant habitat types (i.e., benthic 'orange' mats, marginal 'black' mats, and bare sediments). Like bulk POM, diatom cell concentrations followed a clockwise hysteresis pattern with stream discharge over the daily flow cycles, indicating supply limitation. Diatom community analyses showed that different habitat types harbor distinct diatom communities, and mixing models revealed that a substantial proportion of POM diatoms originated from bare sediments during baseflow conditions. Meanwhile, orange and black mats contribute diatoms to POM primarily during daily flow peaks when both cell concentrations and discharge are highest, making mats the most important contributors to POM diatom assemblages at high flows. These observations may help explain the presence of mat-derived diatoms in hyporheic sediments. Our results thus indicate a varying importance of different in-stream habitats to POM generation and export on daily to seasonal timescales, with implications for biogeochemical cycling and the local diatom metacommunity.
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Affiliation(s)
- Lee F. Stanish
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, United States
| | - Tyler J. Kohler
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, United States
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Joshua Darling
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, United States
| | - Diane M. McKnight
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, United States
- Department of Civil and Environmental Engineering, University of Colorado, Boulder, CO, United States
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2
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Bonanno E, Blöschl G, Klaus J. Discharge, Groundwater Gradients, and Streambed Micro-Topography Control the Temporal Dynamics of Transient Storage in a Headwater Reach. WATER RESOURCES RESEARCH 2023; 59:e2022WR034053. [PMID: 38440781 PMCID: PMC10909551 DOI: 10.1029/2022wr034053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 06/13/2023] [Accepted: 06/17/2023] [Indexed: 03/06/2024]
Abstract
Contradictory interpretations of transient storage modeling (TSM) results of past studies hamper the understanding of how hydrologic conditions control solute transport in streams. To address this issue, we conduct 30 instantaneous tracer experiments in the Weierbach stream, Luxembourg. Using an iterative modeling approach, we calibrate TSM parameters and assess their identifiability across various hydrologic conditions. Near-stream groundwater monitoring wells and LIDAR scans of the streambed are used to evaluate the area of the hyporheic zone and of the submerged sediments for each experiment. Our findings show that increasing discharge enhances parameters interaction requiring more samples of TSM parameters to obtain identifiable results. Our results also indicate that transient storage at the study site is influenced by in-stream and hyporheic exchange processes during low discharge, likely due to the hyporheic zone's large extent and the relatively low water level compared to the size of slate fragments on the streambed. However, as discharge increases, in-stream storage zones become part of the advective channel and the lower localized stream water losses to the adjacent groundwater suggests a decrease of the hyporheic exchange on transient storage. The results obtained were utilized to generate a hydrograph for the study site illustrating the dynamic evolution of in-stream and hyporheic storage with varying discharge, providing insights into the expected influence of different transient storage processes prior to tracer experiments. Overall, our study enhances the understanding of the role of the hyporheic area and in-stream storage zones in transient storage and helps estimate TSM parameters more accurately.
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Affiliation(s)
- Enrico Bonanno
- Catchment and Eco‐Hydrology GroupLuxembourg Institute of Science and TechnologyBelvauxLuxembourg
- Institute of Hydraulic and Water Resources EngineeringVienna University of TechnologyViennaAustria
| | - Günter Blöschl
- Institute of Hydraulic and Water Resources EngineeringVienna University of TechnologyViennaAustria
| | - Julian Klaus
- Institute of GeographyUniversity of BonnBonnGermany
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3
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Zoumplis A, Kolody B, Kaul D, Zheng H, Venepally P, McKnight DM, Takacs-Vesbach C, DeVries A, Allen AE. Impact of meltwater flow intensity on the spatiotemporal heterogeneity of microbial mats in the McMurdo Dry Valleys, Antarctica. ISME COMMUNICATIONS 2023; 3:3. [PMID: 36690784 PMCID: PMC9870883 DOI: 10.1038/s43705-022-00202-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 11/13/2022] [Accepted: 11/16/2022] [Indexed: 01/24/2023]
Abstract
The meltwater streams of the McMurdo Dry Valleys are hot spots of biological diversity in the climate-sensitive polar desert landscape. Microbial mats, largely comprised of cyanobacteria, dominate the streams which flow for a brief window of time (~10 weeks) over the austral summer. These communities, critical to nutrient and carbon cycling, display previously uncharacterized patterns of rapid destabilization and recovery upon exposure to variable and physiologically detrimental conditions. Here, we characterize changes in biodiversity, transcriptional responses and activity of microbial mats in response to hydrological disturbance over spatiotemporal gradients. While diverse metabolic strategies persist between marginal mats and main channel mats, data collected from 4 time points during the austral summer revealed a homogenization of the mat communities during the mid-season peak meltwater flow, directly influencing the biogeochemical roles of this stream ecosystem. Gene expression pattern analyses identified strong functional sensitivities of nitrogen-fixing marginal mats to changes in hydrological activities. Stress response markers detailed the environmental challenges of each microhabitat and the molecular mechanisms underpinning survival in a polar desert ecosystem at the forefront of climate change. At mid and end points in the flow cycle, mobile genetic elements were upregulated across all mat types indicating high degrees of genome evolvability and transcriptional synchronies. Additionally, we identified novel antifreeze activity in the stream microbial mats indicating the presence of ice-binding proteins (IBPs). Cumulatively, these data provide a new view of active intra-stream diversity, biotic interactions and alterations in ecosystem function over a high-flow hydrological regime.
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Affiliation(s)
- A Zoumplis
- Scripps Institution of Oceanography, University of California, San Diego, CA, USA
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - B Kolody
- Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA
| | - D Kaul
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - H Zheng
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - P Venepally
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - D M McKnight
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA
| | - C Takacs-Vesbach
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - A DeVries
- Evolution, Ecology and Behavior, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - A E Allen
- Scripps Institution of Oceanography, University of California, San Diego, CA, USA.
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA.
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4
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Koppel DJ, Av Price G, Brown KE, Adams MS, King CK, Gore DB, Jolley DF. Assessing metal contaminants in Antarctic soils using diffusive gradients in thin-films. CHEMOSPHERE 2021; 269:128675. [PMID: 33657749 DOI: 10.1016/j.chemosphere.2020.128675] [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: 06/29/2020] [Revised: 10/08/2020] [Accepted: 10/16/2020] [Indexed: 06/12/2023]
Abstract
Metal contaminants in Antarctic soils are typically found around research stations which are concentrated in ice-free coastal areas. The risk of these contaminants to the Antarctic environment is not well understood, given Antarctica's unique organisms and climate. This study assessed the use of diffusive gradients in thin-films (DGT), a passive sampler that measures fluxes of labile metals from soils to porewaters, in Antarctic soils. DGT-labile measurements were compared to three chemical extractants of increasing strength including high-purity water, dilute acid (1 M HCl), and concentrated acids (3:1 v/v HNO3:HCl), to understand differences in contaminant geochemistry that may affect environmental risk. One site had high lead concentrations measured with dilute (114 ± 4 mg kg-1) and concentrated (150 ± 10 mg kg-1) acids, while DGT-labile concentrations were below the method detection limit (0.5 μg L-1), indicating that the lead species has low solubility or lability. Another site had low concentrations of zinc measured by dilute (36.2 ± 0.5 mg kg-1) or concentrated (76 ± 6 mg kg-1) acid extracts, but had high DGT-labile concentrations (350 ± 80 μg L-1). This reflects an active source of zinc supplied from soil to pore water over time. Copper was found to be acid extractable, water-soluble, and DGT-labile, with DGT-labile concentrations of up to 12 μg L-1. Despite the soil and metal-specific geochemical differences, any of the extracts could be used with statistical clustering techniques to identify differences in sites with elevated metal concentrations. This study shows that the DGT-method can identify contaminated sites comparably to chemical extracts but provides environmentally relevant measurements of metal contaminant lability in Antarctic soils.
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Affiliation(s)
- Darren J Koppel
- Faculty of Science, University of Technology Sydney, NSW, Australia; Faculty of Science Medicine and Health, University of Wollongong, NSW, Australia; CSIRO Land and Water, Lucas Heights, NSW, Australia.
| | - Gwilym Av Price
- Faculty of Science, University of Technology Sydney, NSW, Australia; CSIRO Land and Water, Lucas Heights, NSW, Australia
| | - Kathryn E Brown
- Australian Antarctic Division, Kingston, Tasmania, Australia
| | | | | | - Damian B Gore
- Department of Earth and Environmental Sciences, Macquarie University, NSW, Australia
| | - Dianne F Jolley
- Faculty of Science Medicine and Health, University of Wollongong, NSW, Australia; CSIRO Land and Water, Lucas Heights, NSW, Australia
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5
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Kohler TJ, Peter H, Fodelianakis S, Pramateftaki P, Styllas M, Tolosano M, de Staercke V, Schön M, Busi SB, Wilmes P, Washburne A, Battin TJ. Patterns and Drivers of Extracellular Enzyme Activity in New Zealand Glacier-Fed Streams. Front Microbiol 2020; 11:591465. [PMID: 33329472 PMCID: PMC7711088 DOI: 10.3389/fmicb.2020.591465] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 10/27/2020] [Indexed: 11/17/2022] Open
Abstract
Glacier-fed streams (GFSs) exhibit near-freezing temperatures, variable flows, and often high turbidities. Currently, the rapid shrinkage of mountain glaciers is altering the delivery of meltwater, solutes, and particulate matter to GFSs, with unknown consequences for their ecology. Benthic biofilms dominate microbial life in GFSs, and play a major role in their biogeochemical cycling. Mineralization is likely an important process for microbes to meet elemental budgets in these systems due to commonly oligotrophic conditions, and extracellular enzymes retained within the biofilm enable the degradation of organic matter and acquisition of carbon (C), nitrogen (N), and phosphorus (P). The measurement and comparison of these extracellular enzyme activities (EEA) can in turn provide insight into microbial elemental acquisition effort relative to environmental availability. To better understand how benthic biofilm communities meet resource demands, and how this might shift as glaciers vanish under climate change, we investigated biofilm EEA in 20 GFSs varying in glacier influence from New Zealand’s Southern Alps. Using turbidity and distance to the glacier snout normalized for glacier size as proxies for glacier influence, we found that bacterial abundance (BA), chlorophyll a (Chl a), extracellular polymeric substances (EPS), and total EEA per gram of sediment increased with decreasing glacier influence. Yet, when normalized by BA, EPS decreased with decreasing glacier influence, Chl a still increased, and there was no relationship with total EEA. Based on EEA ratios, we found that the majority of GFS microbial communities were N-limited, with a few streams of different underlying bedrock geology exhibiting P-limitation. Cell-specific C-acquiring EEA was positively related to the ratio of Chl a to BA, presumably reflecting the utilization of algal exudates. Meanwhile, cell-specific N-acquiring EEA were positively correlated with the concentration of dissolved inorganic nitrogen (DIN), and both N- and P-acquiring EEA increased with greater cell-specific EPS. Overall, our results reveal greater glacier influence to be negatively related to GFS biofilm biomass parameters, and generally associated with greater microbial N demand. These results help to illuminate the ecology of GFS biofilms, along with their biogeochemical response to a shifting habitat template with ongoing climate change.
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Affiliation(s)
- Tyler J Kohler
- Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Hannes Peter
- Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Stilianos Fodelianakis
- Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Paraskevi Pramateftaki
- Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Michail Styllas
- Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Matteo Tolosano
- Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Vincent de Staercke
- Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Martina Schön
- Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Susheel Bhanu Busi
- Systems Ecology Research Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Paul Wilmes
- Systems Ecology Research Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Alex Washburne
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States.,Selva Analytics, LLC, Bozeman, MT, United States
| | - Tom J Battin
- Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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6
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Coyne KJ, Parker AE, Lee CK, Sohm JA, Kalmbach A, Gunderson T, León-Zayas R, Capone DG, Carpenter EJ, Cary SC. The distribution and relative ecological roles of autotrophic and heterotrophic diazotrophs in the McMurdo Dry Valleys, Antarctica. FEMS Microbiol Ecol 2020; 96:5714082. [PMID: 31967635 PMCID: PMC7043275 DOI: 10.1093/femsec/fiaa010] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 01/21/2020] [Indexed: 12/13/2022] Open
Abstract
The McMurdo Dry Valleys (MDV) in Antarctica harbor a diverse assemblage of mat-forming diazotrophic cyanobacteria that play a key role in nitrogen cycling. Prior research showed that heterotrophic diazotrophs also make a substantial contribution to nitrogen fixation in MDV. The goals of this study were to survey autotrophic and heterotrophic diazotrophs across the MDV to investigate factors that regulate the distribution and relative ecological roles of each group. Results indicated that diazotrophs were present only in samples with mats, suggesting a metabolic coupling between autotrophic and heterotrophic diazotrophs. Analysis of 16S rRNA and nifH gene sequences also showed that diazotrophs were significantly correlated to the broader bacterial community, while co-occurrence network analysis revealed potential interspecific interactions. Consistent with previous studies, heterotrophic diazotrophs in MDV were diverse, but largely limited to lakes and their outlet streams, or other environments protected from desiccation. Despite the limited distribution, heterotrophic diazotrophs may make a substantial contribution to the nitrogen budget of MDV due to larger surface area and longer residence times of lakes. This work contributes to our understanding of key drivers of bacterial community structure in polar deserts and informs future efforts to investigate the contribution of nitrogen fixation to MDV ecosystems.
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Affiliation(s)
- Kathryn J Coyne
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE 19958, USA
| | - Alexander E Parker
- Estuary and Ocean Science Center, San Francisco State University, Tiburon, CA 94920, USA
| | - Charles K Lee
- International Centre for Terrestrial Antarctic Research, School of Science, University of Waikato, Hamilton 3240, New Zealand
| | - Jill A Sohm
- Wrigley Institute for Environmental Studies and Department of Biological Sciences, University of Southern California, Los Angeles, CA 9008-037, USA
| | - Andrew Kalmbach
- Estuary and Ocean Science Center, San Francisco State University, Tiburon, CA 94920, USA
| | - Troy Gunderson
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 9008-037, USA
| | - Rosa León-Zayas
- Willamette University, Biology Department, Salem, OR 97301, USA
| | - Douglas G Capone
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 9008-037, USA
| | - Edward J Carpenter
- Estuary and Ocean Science Center, San Francisco State University, Tiburon, CA 94920, USA
| | - S Craig Cary
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE 19958, USA.,International Centre for Terrestrial Antarctic Research, School of Science, University of Waikato, Hamilton 3240, New Zealand
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7
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Sohm JA, Niederberger TD, Parker AE, Tirindelli J, Gunderson T, Cary SC, Capone DG, Carpenter EJ. Microbial Mats of the McMurdo Dry Valleys, Antarctica: Oases of Biological Activity in a Very Cold Desert. Front Microbiol 2020; 11:537960. [PMID: 33193125 PMCID: PMC7654227 DOI: 10.3389/fmicb.2020.537960] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 09/28/2020] [Indexed: 11/29/2022] Open
Abstract
Cyanobacterial mats in the Antarctic Dry Valleys are photosynthetic microbial ecosystems living at the extreme of conditions on Earth with respect to temperature, light, water and nutrient availability. They are metabolically active for about 8 weeks during the austral summer when temperatures briefly rise above freezing and glacial and lake melt waters are available. There is much to learn about the biogeochemical impact of mats in these environments and the microbial communities associated with them. Our data demonstrate that these mats attain surprisingly high rates of carbon (CO2) and dinitrogen (N2) fixation when liquid water is available, in some cases comparable to rates in warmer temperate or tropical environments. C and N2 fixation in Dry Valley mats in turn substantially elevate dissolved organic C and inorganic N pools and thereby promote enhanced microbial secondary production. Moreover, the microbial community fingerprint of these mats is unique compared with the more ubiquitous dry soils that do not contain mats. Components of the heterotrophic microbiota may also contribute substantially to N inputs through N2 fixation.
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Affiliation(s)
- Jill A Sohm
- Department of Biological Sciences, Marine and Environmental Biology Section, University of Southern California, Los Angeles, CA, United States.,Environmental Studies Program, University of Southern California, Los Angeles, CA, United States
| | - Thomas D Niederberger
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE, United States
| | - Alexander E Parker
- Estuary and Ocean Science Center, San Francisco State University, Tiburon, CA, United States.,Department of Sciences and Mathematics, California State University Maritime Academy, Vallejo, CA, United States
| | - Joëlle Tirindelli
- Estuary and Ocean Science Center, San Francisco State University, Tiburon, CA, United States
| | - Troy Gunderson
- Department of Biological Sciences, Marine and Environmental Biology Section, University of Southern California, Los Angeles, CA, United States
| | - Stephen Craig Cary
- College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE, United States.,International Centre for Terrestrial Antarctic Research, University of Waikato, Hamilton, New Zealand
| | - Douglas G Capone
- Department of Biological Sciences, Marine and Environmental Biology Section, University of Southern California, Los Angeles, CA, United States
| | - Edward J Carpenter
- Estuary and Ocean Science Center, San Francisco State University, Tiburon, CA, United States
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8
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Comparison of Diatom Paleo-Assemblages with Adjacent Limno-Terrestrial Communities on Vega Island, Antarctic Peninsula. WATER 2020. [DOI: 10.3390/w12051340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Diatoms are useful ecological and paleolimnological indicators routinely used to reconstruct past conditions and monitor environmental change. Despite this, diatom assemblages from lake sediment cores are often difficult to interpret due to a limited knowledge of the ecology of some species, some of which may originate from the adjacent limno-terrestrial landscape. Here, we compare diatom assemblages from two recently published Antarctic lake sediment cores collected from the northeast and southwest sides of Vega Island, Antarctic Peninsula. We further compare the sediment core assemblages with adjacent modern communities inhabiting four different limno-terrestrial habitat types to gauge the importance of landscape connectivity in determining paleo-assemblage structure. We found that diatom assemblage composition was significantly different between the two cores, and our survey of modern habitats further revealed habitat type to be an important factor determining the composition of limno-terrestrial samples. Differences in modern habitats were driven primarily by Chamaepinnularia krookiformis in mosses, Nitzschia paleacea in ponds, and Fistulifera pelliculosa in streams. When modern communities were compared with paleo-assemblages through ordination, the cored lake from the northeast side, which exhibited greater hydrological connectivity with its surroundings, clustered more closely with the adjacent modern samples. Meanwhile, the cored lake from the southwest side, which was more hydrologically isolated, formed a distinct cluster separate from the others. Overall, species richness and diversity were greater on the southwest side of the island than the northeast, and the known distributions of diatom taxa supported the notion that Vega Island was a transitional zone between the Maritime and Continental Antarctic bioregions. These results collectively suggested that while environmental and spatial controls may be influential in determining diatom community composition, the unique hydrogeological setting of individual waterbodies was an important consideration for determining the assemblage structure of lake cores. This paper furthermore expanded ongoing research of diatom diversity and distributions on maritime Antarctic islands, which will improve diatom-based interpretations for regional ecological monitoring and paleolimnology in the future.
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9
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Li R, Wang Y, Qian J, Fu Y. Evaluating transient storage and associated nutrient retention in a nutrient-rich headwater stream: a case study in Lake Chaohu Basin, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:6066-6077. [PMID: 31865564 DOI: 10.1007/s11356-019-07349-3] [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: 09/09/2019] [Accepted: 12/09/2019] [Indexed: 06/10/2023]
Abstract
Transient storage has been studied intensively in small streams, but some processes and mechanisms are not yet entirely understood regarding this issue, especially in chronically nutrient-enriched streams. The exploration of transient storage dynamics in nutrient-rich headwater streams has great significance for stream nutrient management in China and other developing countries, which are suffering from eutrophication. In the present study, we conducted five instantaneous slug additions composed of a conservative tracer dissolved with two nonconservative nutrients injections in a suburban small stream (Guanzhen Creek), Lake Chaohu Basin, China. Transient storage metrics were estimated using the model-fitted hydrologic parameters from the one-dimensional transport with inflow and storage (OTIS) model. Regression analyses were performed to examine the relationship between hydraulic parameters and transient storage metrics. Moreover, nitrogen and phosphorus retention efficiency was qualitatively evaluated based on the OTIS model-fitted nutrient parameters. Our results showed that the OTIS model-fitted hydrologic parameters in Guanzhen Creek were within the range of previously published literature. The transient storage metrics of Guanzhen Creek were generally comparable to those in streams with low-to-moderate nutrient levels in other catchments. Moreover, most of the transient storage metrics showed a strong relationship with stream discharge, while only hydrological retention factor showed a markedly negative correlation with flow rate. Given the negative uptake rates for NH4-N and SRP in half cases, we reasonably concluded that Guanzhen Creek was hardly incapable of retaining nitrogen and phosphorus.
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Affiliation(s)
- Ruzhong Li
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China.
- Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei, 230009, China.
| | - Yuqing Wang
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
- Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei, 230009, China
| | - Jing Qian
- Anhui Research Academy of Environmental Sciences, Hefei, 230006, China
| | - Yang Fu
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
- Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei, 230009, China
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10
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Valdespino-Castillo PM, Cerqueda-García D, Espinosa AC, Batista S, Merino-Ibarra M, Taş N, Alcántara-Hernández RJ, Falcón LI. Microbial distribution and turnover in Antarctic microbial mats highlight the relevance of heterotrophic bacteria in low-nutrient environments. FEMS Microbiol Ecol 2019; 94:5047302. [PMID: 29982398 DOI: 10.1093/femsec/fiy129] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 06/04/2018] [Indexed: 11/14/2022] Open
Abstract
Maritime Antarctica has shown the highest increase in temperature in the Southern Hemisphere. Under this scenario, biogeochemical cycles may be altered, resulting in rapid environmental change for Antarctic biota. Microbes that drive biogeochemical cycles often form biofilms or microbial mats in continental meltwater environments. Limnetic microbial mats from the Fildes Peninsula were studied using high-throughput 16S rRNA gene sequencing. Mat samples were collected from 15 meltwater stream sites, comprising a natural gradient from ultraoligotrophic glacier flows to meltwater streams exposed to anthropogenic activities. Our analyses show that microbial community structure differences between mats are explained by environmental NH4+, NO3-, DIN, soluble reactive silicon and conductivity. Microbial mats living under ultraoligotrophic meltwater conditions did not exhibit a dominance of cyanobacterial photoautotrophs, as has been documented for other Antarctic limnetic microbial mats. Instead, ultraoligotrophic mat communities were characterized by the presence of microbes recognized as heterotrophs and photoheterotrophs. This suggests that microbial capabilities for recycling organic matter may be a key factor to dwell in ultra-low nutrient conditions. Our analyses show that phylotype level assemblages exhibit coupled distribution patterns in environmental oligotrophic inland waters. The evaluation of these microbes suggests the relevance of reproductive and structural strategies to pioneer these psychrophilic ultraoligotrophic environments.
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Affiliation(s)
| | - Daniel Cerqueda-García
- Laboratorio de Ecología Bacteriana, Instituto de Ecología, Universidad Nacional Autónoma de México, CDMX, 04510, Mexico
| | - Ana Cecilia Espinosa
- LANCIS, Instituto de Ecología, Universidad Nacional Autónoma de México, CDMX, 04510, Mexico
| | - Silvia Batista
- Unidad de Microbiología Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, 11600, Uruguay
| | - Martín Merino-Ibarra
- Unidad Académica de Ecología y Biodiversidad Acuática, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, CDMX, 04510, Mexico
| | - Neslihan Taş
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, US
| | | | - Luisa I Falcón
- Laboratorio de Ecología Bacteriana, Instituto de Ecología, Universidad Nacional Autónoma de México, CDMX, 04510, Mexico
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11
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Lambrechts S, Willems A, Tahon G. Uncovering the Uncultivated Majority in Antarctic Soils: Toward a Synergistic Approach. Front Microbiol 2019; 10:242. [PMID: 30828325 PMCID: PMC6385771 DOI: 10.3389/fmicb.2019.00242] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/29/2019] [Indexed: 01/22/2023] Open
Abstract
Although Antarctica was once believed to be a sterile environment, it is now clear that the microbial communities inhabiting the Antarctic continent are surprisingly diverse. Until the beginning of the new millennium, little was known about the most abundant inhabitants of the continent: prokaryotes. From then on, however, the rising use of deep sequencing techniques has led to a better understanding of the Antarctic prokaryote diversity and provided insights in the composition of prokaryotic communities in different Antarctic environments. Although these cultivation-independent approaches can produce millions of sequences, linking these data to organisms is hindered by several problems. The largest difficulty is the lack of biological information on large parts of the microbial tree of life, arising from the fact that most microbial diversity on Earth has never been characterized in laboratory cultures. These unknown prokaryotes, also known as microbial dark matter, have been dominantly detected in all major environments on our planet. Laboratory cultures provide access to the complete genome and the means to experimentally verify genomic predictions and metabolic functions and to provide evidence of horizontal gene transfer. Without such well-documented reference data, microbial dark matter will remain a major blind spot in deep sequencing studies. Here, we review our current understanding of prokaryotic communities in Antarctic ice-free soils based on cultivation-dependent and cultivation-independent approaches. We discuss advantages and disadvantages of both approaches and how these strategies may be combined synergistically to strengthen each other and allow a more profound understanding of prokaryotic life on the frozen continent.
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Affiliation(s)
- Sam Lambrechts
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | | | - Guillaume Tahon
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
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12
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Vigneron A, Cruaud P, Mohit V, Martineau MJ, Culley AI, Lovejoy C, Vincent WF. Multiple Strategies for Light-Harvesting, Photoprotection, and Carbon Flow in High Latitude Microbial Mats. Front Microbiol 2018; 9:2881. [PMID: 30564204 PMCID: PMC6288179 DOI: 10.3389/fmicb.2018.02881] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 11/09/2018] [Indexed: 12/27/2022] Open
Abstract
Microbial mats are ubiquitous in polar freshwater ecosystems and sustain high concentrations of biomass despite the extreme seasonal variations in light and temperature. Here we aimed to resolve genomic adaptations for light-harvesting, bright-light protection, and carbon flow in mats that undergo seasonal freeze-up. To bracket a range of communities in shallow water habitats, we sampled cyanobacterial mats in the thawed littoral zone of two lakes situated at the northern and southern limits of the Canadian Arctic permafrost zone. We applied a multiphasic approach using pigment profiles from high performance liquid chromatography, Illumina MiSeq sequencing of the 16S and 18S rRNA genes, and metagenomic analysis. The mats shared a taxonomic and functional core microbiome, dominated by oxygenic cyanobacteria with light-harvesting and photoprotective pigments, bacteria with bacteriochlorophyll, and bacteria with light-driven Type I rhodopsins. Organisms able to use light for energy related processes represented up to 85% of the total microbial community, with 15–30% attributable to cyanobacteria and 55–70% attributable to other bacteria. The proportion of genes involved in anaplerotic CO2 fixation was greater than for genes associated with oxygenic photosynthesis. Diverse heterotrophic bacteria, eukaryotes (including metazoans and fungi) and viruses co-occurred in both communities. The results indicate a broad range of strategies for capturing sunlight and CO2, and for the subsequent flow of energy and carbon in these complex, light-driven microbial ecosystems.
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Affiliation(s)
- Adrien Vigneron
- Centre d'Études Nordiques, Takuvik Joint International Laboratory, Université Laval, Québec, QC, Canada.,Département de Biologie, Université Laval, Québec, QC, Canada.,Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
| | - Perrine Cruaud
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada.,Département de Biochimie, de Microbiologie et de Bio-informatique, Université Laval, Québec, QC, Canada
| | - Vani Mohit
- Centre d'Études Nordiques, Takuvik Joint International Laboratory, Université Laval, Québec, QC, Canada.,Département de Biologie, Université Laval, Québec, QC, Canada.,Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
| | - Marie-Josée Martineau
- Centre d'Études Nordiques, Takuvik Joint International Laboratory, Université Laval, Québec, QC, Canada.,Département de Biologie, Université Laval, Québec, QC, Canada
| | - Alexander I Culley
- Centre d'Études Nordiques, Takuvik Joint International Laboratory, Université Laval, Québec, QC, Canada.,Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada.,Département de Biochimie, de Microbiologie et de Bio-informatique, Université Laval, Québec, QC, Canada
| | - Connie Lovejoy
- Centre d'Études Nordiques, Takuvik Joint International Laboratory, Université Laval, Québec, QC, Canada.,Département de Biologie, Université Laval, Québec, QC, Canada.,Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
| | - Warwick F Vincent
- Centre d'Études Nordiques, Takuvik Joint International Laboratory, Université Laval, Québec, QC, Canada.,Département de Biologie, Université Laval, Québec, QC, Canada.,Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada
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13
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14
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Liu Y, Xu F, Liu C. Coupled Hydro-Biogeochemical Processes Controlling Cr Reductive Immobilization in Columbia River Hyporheic Zone. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:1508-1517. [PMID: 27996242 DOI: 10.1021/acs.est.6b05099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An experiment and modeling study was conducted to investigate coupled hydro-biogeochemical processes controlling reductive immobilization of groundwater Cr in the hyporheic zone (HZ) at the U.S. Department of Energy's Hanford Site, where dynamic surface water-groundwater exchange occurs on a daily basis. Experiments were performed to calibrate kinetic models, and the calibrated models were incorporated into a multicomponent reactive transport model to simulate Cr redox transformation and immobilization under field hydrological conditions. The results revealed that the rates of Cr(VI) reduction, Cr(III) accumulation, and Cr(VI) release to the river are mostly affected by dynamic sediment redox conditions represented by Fe(II) reactivity, which is controlled by its cyclic interaction with O2 carried by river water, microbial activities, and the supply and bioavailability of organic carbon (OC) that is present in the HZ and/or carried by transport. In addition, the HZ geophysical properties including hydraulic conductivity and the thickness of the top alluvial layer have a significant influence on Cr reactive transport and immobilization by controlling residence times for reactions and the supply rates of O2, Cr, and OC into the HZ. The results provide important insights into the dynamic redox environments in the HZ that can reductively immobilize contaminants.
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Affiliation(s)
- Yuanyuan Liu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
| | - Fen Xu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- School of Environmental Studies, China University of Geosciences , Wuhan 430074, China
| | - Chongxuan Liu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- School of Environmental Science and Engineering, Southern University of Science and Technology , Shenzhen 518055, China
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15
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Van Horn DJ, Wolf CR, Colman DR, Jiang X, Kohler TJ, McKnight DM, Stanish LF, Yazzie T, Takacs-Vesbach CD. Patterns of bacterial biodiversity in the glacial meltwater streams of the McMurdo Dry Valleys, Antarctica. FEMS Microbiol Ecol 2016; 92:fiw148. [PMID: 27495241 DOI: 10.1093/femsec/fiw148] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2016] [Indexed: 12/26/2022] Open
Abstract
Microbial consortia dominate glacial meltwater streams from polar regions, including the McMurdo Dry Valleys (MDV), where they thrive under physiologically stressful conditions. In this study, we examined microbial mat types and sediments found in 12 hydrologically diverse streams to describe the community diversity and composition within and across sites. Sequencing of the 16S rRNA gene from 129 samples revealed ∼24 000 operational taxonomic units (<97% DNA similarity), making streams the most biodiverse habitat in the MDV. Principal coordinate analyses revealed significant but weak clustering by mat type across all streams (ANOSIM R-statistic = 0.28) but stronger clustering within streams (ANOSIM R-statistic from 0.28 to 0.94). Significant relationships (P < 0.05) were found between bacterial diversity and mat ash-free dry mass, suggesting that diversity is related to the hydrologic regimes of the various streams, which are predictive of mat biomass. However, correlations between stream chemistry and community members were weak, possibly reflecting the importance of internal processes and hydrologic conditions. Collectively, these results suggest that localized conditions dictate bacterial community composition of the same mat types and sediments from different streams, and while MDV streams are hotspots of biodiversity in an otherwise depauperate landscape, controls on community structure are complex and site specific.
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Affiliation(s)
- David J Van Horn
- Department of Biology, University of New Mexico MSCO3 2020, 1 UNM, Albuquerque, NM 87131, USA
| | - Caitlin R Wolf
- Department of Biology, University of New Mexico MSCO3 2020, 1 UNM, Albuquerque, NM 87131, USA
| | - Daniel R Colman
- Department of Biology, University of New Mexico MSCO3 2020, 1 UNM, Albuquerque, NM 87131, USA
| | - Xiaoben Jiang
- Department of Biology, University of New Mexico MSCO3 2020, 1 UNM, Albuquerque, NM 87131, USA
| | - Tyler J Kohler
- Faculty of Science, Department of Ecology, Charles University in Prague, Viničná 7, 12844 Prague 2, Prague, Czech Republic
| | - Diane M McKnight
- Institute of Arctic and Alpine Research, University of Colorado, 1560 30th Street, Boulder, CO 80303, USA
| | - Lee F Stanish
- National Ecological Observatory Network, 1685 38th Street, Boulder, CO, 80301
| | - Terrill Yazzie
- Department of Biology, University of New Mexico MSCO3 2020, 1 UNM, Albuquerque, NM 87131, USA
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16
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Kohler TJ, Van Horn DJ, Darling JP, Takacs-Vesbach CD, McKnight DM. Nutrient treatments alter microbial mat colonization in two glacial meltwater streams from the McMurdo Dry Valleys, Antarctica. FEMS Microbiol Ecol 2016; 92:fiw049. [PMID: 26940086 DOI: 10.1093/femsec/fiw049] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2016] [Indexed: 01/06/2023] Open
Abstract
Microbial mats are abundant in many alpine and polar aquatic ecosystems. With warmer temperatures, new hydrologic pathways are developing in these regions and increasing dissolved nutrient fluxes. In the McMurdo Dry Valleys, thermokarsting may release both nutrients and sediment, and has the potential to influence mats in glacial meltwater streams. To test the role of nutrient inputs on community structure, we created nutrient diffusing substrata (NDS) with agar enriched in N, P and N + P, with controls, and deployed them into two Dry Valley streams. We found N amendments (N and N + P) to have greater chlorophyll-a concentrations, total algal biovolume, more fine filamentous cyanobacteria and a higher proportion of live diatoms than other treatments. Furthermore, N treatments were substantially elevated in Bacteroidetes and the small diatom, Fistulifera pelliculosa. On the other hand, species richness was almost double in P and N + P treatments over others, and coccoid green algae and Proteobacteria were more abundant in both streams. Collectively, these data suggest that nutrients have the potential to stimulate growth and alter community structure in glacial meltwater stream microbial mats, and the recent erosion of permafrost and accelerated glacial melt will likely impact resident biota in polar lotic systems here and elsewhere.
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Affiliation(s)
- Tyler J Kohler
- Institute of Arctic and Alpine Research, University of Colorado, 1560 30th Street, Boulder, CO 80303, USA Faculty of Science, Department of Ecology, Charles University in Prague, Viničná 7, 12844 Prague 2, Prague, Czech Republic
| | - David J Van Horn
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Joshua P Darling
- Institute of Arctic and Alpine Research, University of Colorado, 1560 30th Street, Boulder, CO 80303, USA
| | | | - Diane M McKnight
- Institute of Arctic and Alpine Research, University of Colorado, 1560 30th Street, Boulder, CO 80303, USA
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17
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Niederberger TD, Sohm JA, Gunderson T, Tirindelli J, Capone DG, Carpenter EJ, Cary SC. Carbon-Fixation Rates and Associated Microbial Communities Residing in Arid and Ephemerally Wet Antarctic Dry Valley Soils. Front Microbiol 2015; 6:1347. [PMID: 26696969 PMCID: PMC4673872 DOI: 10.3389/fmicb.2015.01347] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 11/16/2015] [Indexed: 11/13/2022] Open
Abstract
Carbon-fixation is a critical process in severely oligotrophic Antarctic Dry Valley (DV) soils and may represent the major source of carbon in these arid environments. However, rates of C-fixation in DVs are currently unknown and the microorganisms responsible for these activities unidentified. In this study, C-fixation rates measured in the bulk arid soils (<5% moisture) ranged from below detection limits to ∼12 nmol C/cc/h. Rates in ephemerally wet soils ranged from ∼20 to 750 nmol C/cc/h, equating to turnover rates of ∼7-140 days, with lower rates in stream-associated soils as compared to lake-associated soils. Sequencing of the large subunit of RuBisCO (cbbL) in these soils identified green-type sequences dominated by the 1B cyanobacterial phylotype in both arid and wet soils including the RNA fraction of the wet soil. Red-type cbbL genes were dominated by 1C actinobacterial phylotypes in arid soils, with wetted soils containing nearly equal proportions of 1C (actinobacterial and proteobacterial signatures) and 1D (algal) phylotypes. Complementary 16S rRNA and 18S rRNA gene sequencing also revealed distinct differences in community structure between biotopes. This study is the first of its kind to examine C-fixation rates in DV soils and the microorganisms potentially responsible for these activities.
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Affiliation(s)
| | - Jill A. Sohm
- Wrigley Institute of Environmental Studies and Department of Biological Science, University of Southern CaliforniaLos Angeles, CA, USA
| | - Troy Gunderson
- Wrigley Institute of Environmental Studies and Department of Biological Science, University of Southern CaliforniaLos Angeles, CA, USA
| | - Joëlle Tirindelli
- Romberg Tiburon Center, San Francisco State UniversityTiburon, CA, USA
| | - Douglas G. Capone
- Wrigley Institute of Environmental Studies and Department of Biological Science, University of Southern CaliforniaLos Angeles, CA, USA
| | | | - S. Craig Cary
- College of Marine and Earth Sciences, University of DelawareLewes, DE, USA
- International Centre for Terrestrial Antarctic Research, University of WaikatoHamilton, New Zealand
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18
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Smidt SJ, Cullin JA, Ward AS, Robinson J, Zimmer MA, Lautz LK, Endreny TA. A Comparison of Hyporheic Transport at a Cross-Vane Structure and Natural Riffle. GROUND WATER 2015; 53:859-871. [PMID: 25408169 DOI: 10.1111/gwat.12288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 09/09/2014] [Indexed: 06/04/2023]
Abstract
While restoring hyporheic flowpaths has been cited as a benefit to stream restoration structures, little documentation exists confirming that constructed restoration structures induce comparable hyporheic exchange to natural stream features. This study compares a stream restoration structure (cross-vane) to a natural feature (riffle) concurrently in the same stream reach using time-lapsed electrical resistivity (ER) tomography. Using this hydrogeophysical approach, we were able to quantify hyporheic extent and transport beneath the cross-vane structure and the riffle. We interpret from the geophysical data that the cross-vane and the natural riffle induced spatially and temporally unique hyporheic extent and transport, and the cross-vane created both spatially larger and temporally longer hyporheic flowpaths than the natural riffle. Tracer from the 4.67-h injection was detected along flowpaths for 4.6 h at the cross-vane and 4.2 h at the riffle. The spatial extent of the hyporheic zone at the cross-vane was 12% larger than that at the riffle. We compare ER results of this study to vertical fluxes calculated from temperature profiles and conclude significant differences in the interpretation of hyporheic transport from these different field techniques. Results of this study demonstrate a high degree of heterogeneity in transport metrics at both the cross-vane and the riffle and differences between the hyporheic flowpath networks at the two different features. Our results suggest that restoration structures may be capable of creating sufficient exchange flux and timescales of transport to achieve the same ecological functions as natural features, but engineering of the physical and biogeochemical environment may be necessary to realize these benefits.
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Affiliation(s)
- Samuel J Smidt
- Department of Earth & Environmental Sciences, The University of Iowa, Iowa City, IA, 52242
| | - Joseph A Cullin
- Department of Earth & Environmental Sciences, The University of Iowa, Iowa City, IA, 52242
| | | | - Jesse Robinson
- Stream Institute, Department of Civil and Environmental Engineering, University of Louisville, Louisville, KY, 40206
| | - Margaret A Zimmer
- Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC, 27708
| | - Laura K Lautz
- Department of Earth Sciences, Syracuse University, Syracuse, NY, 13244
| | - Theodore A Endreny
- Department of Environmental Resources Engineering, SUNY-ESF, Syracuse, NY, 13210
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19
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The ecological role of moss in a polar desert: implications for aboveground–belowground and terrestrial–aquatic linkages. Polar Biol 2014. [DOI: 10.1007/s00300-014-1465-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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Characterization and comparison of potential denitrifiers in microbial mats from King George Island, Maritime Antarctica. Polar Biol 2013. [DOI: 10.1007/s00300-013-1440-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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Cornut J, Clivot H, Chauvet E, Elger A, Pagnout C, Guérold F. Effect of acidification on leaf litter decomposition in benthic and hyporheic zones of woodland streams. WATER RESEARCH 2012; 46:6430-6444. [PMID: 23069077 DOI: 10.1016/j.watres.2012.09.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 09/03/2012] [Accepted: 09/08/2012] [Indexed: 06/01/2023]
Abstract
Anthropogenic acidification has deleterious effects on both structure and functioning of surface water ecosystems. This study examined how it may affect the leaf decomposition rate and the community structure and activity of decomposers in both benthic and hyporheic zones of five headwater streams along an acidification gradient from highly acidic (pH 4.6) to circumneutral (pH 7.4). Overall, responses to acidification in hyporheic zones were less pronounced, but followed the same pattern as in their benthic counterparts. Leaf decomposition was much faster in the circumneutral stream, both in the hyporheic and benthic zones (k = 0.0068 and 0.0534 d(-1), respectively), than in the most acidic one (k = 0.0016 and 0.0055 d(-1), respectively), and correlated well with the acidic gradient in both compartments. Interestingly, leaf litter decomposition was less affected by acidification in hyporheic compared to benthic compartments, likely due to the relatively low sensitivity of fungi, which were the main decomposers of buried coarse particulate organic matter. These results argue in favour of conserving hyporheic habitats in acidified streams as they can maintain matter and species fluxes that are essential to the ecosystem.
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Affiliation(s)
- Julien Cornut
- Université de Toulouse, INP, UPS, Laboratoire Ecologie Fonctionnelle et Environnement, UMR CNRS 5245, Toulouse, France.
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22
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Stanish LF, O'Neill SP, Gonzalez A, Legg TM, Knelman J, McKnight DM, Spaulding S, Nemergut DR. Bacteria and diatom co-occurrence patterns in microbial mats from polar desert streams. Environ Microbiol 2012; 15:1115-31. [PMID: 22998505 DOI: 10.1111/j.1462-2920.2012.02872.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 08/09/2012] [Accepted: 08/13/2012] [Indexed: 12/22/2022]
Abstract
The ephemeral stream habitats of the McMurdo Dry Valleys of Antarctica support desiccation and freeze-tolerant microbial mats that are hot spots of primary productivity in an otherwise inhospitable environment. The ecological processes that structure bacterial communities in this harsh environment are not known; however, insights from diatom community ecology may prove to be informative. We examined the relationships between diatoms and bacteria at the community and taxon levels. The diversity and community structure of stream microbial mats were characterized using high-throughput pyrosequencing for bacteria and morphological identification for diatoms. We found significant relationships between diatom communities and the communities of cyanobacteria and heterotrophic bacteria, and co-occurrence analysis identified numerous correlations between the relative abundances of individual diatom and bacterial taxa, which may result from species interactions. Additionally, the strength of correlations between heterotrophic bacteria and diatoms varied along a hydrologic gradient, indicating that flow regime may influence the overall community structure. Phylogenetic consistency in the co-occurrence patterns suggests that the associations are ecologically relevant. Despite these community- and taxon-level relationships, diatom and bacterial alpha diversity were inversely correlated, which may highlight a fundamental difference between the processes that influence bacterial and diatom community assembly in these streams. Our results therefore demonstrate that the relationships between diatoms and bacteria are complex and may result from species interactions as well as niche-specific processes.
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Affiliation(s)
- Lee F Stanish
- Institute of Arctic and Alpine Research, University of Colorado, 1560 30th St, Campus Box 450, Boulder, Colorado, USA.
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23
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Niederberger TD, Sohm JA, Tirindelli J, Gunderson T, Capone DG, Carpenter EJ, Cary SC. Diverse and highly active diazotrophic assemblages inhabit ephemerally wetted soils of the Antarctic Dry Valleys. FEMS Microbiol Ecol 2012; 82:376-90. [PMID: 22500944 DOI: 10.1111/j.1574-6941.2012.01390.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 04/04/2012] [Accepted: 04/10/2012] [Indexed: 11/28/2022] Open
Abstract
Eolian transport of biomass from ephemerally wetted soils, associated with summer glacial meltwater runoffs and lake edges, to low-productivity areas of the Antarctic Dry Valleys (DV) has been postulated to be an important source of organic matter (fixed nitrogen and fixed carbon) to the entire DV ecosystem. However, descriptions and identification of the microbial members responsible for N(2) fixation within these wetted sites are limited. In this study, N(2) fixers from wetted soils were identified by direct nifH gene sequencing and their in situ N(2) fixation activities documented via acetylene reduction and RNA-based quantitative PCR assays. Shannon-index nifH diversity levels ranged between 1.8 and 2.6 and included the expected cyanobacterial signatures and a large number of phylotypes related to the gamma-, beta-, alpha-, and delta-proteobacteria. N(2) fixation rates ranged between approximately 0.5 and 6 nmol N cm(-3) h(-1) with measurements indicating that approximately 50% of this activity was linked with sulfate reduction at some sites. Comparisons with proximal dry soils also suggested that these communities are not ubiquitously distributed, and conditions unrelated to moisture content may define the composition, diversity, or habitat suitability of the microbial communities within wetted soils of the DVs.
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25
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Stanish LF, Nemergut DR, McKnight DM. Hydrologic processes influence diatom community composition in Dry Valley streams. ACTA ACUST UNITED AC 2011. [DOI: 10.1899/11-008.1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Lee F Stanish
- Environmental Studies Program, Institute of Arctic and Alpine Research, University of Colorado, 1560 30th Street, Campus Box 450, Boulder, Colorado 80309 USA
| | - Diana R Nemergut
- Environmental Studies Program, Institute of Arctic and Alpine Research, University of Colorado, 1560 30th Street, Campus Box 450, Boulder, Colorado 80309 USA
| | - Diane M McKnight
- Department of Civil and Environmental Engineering, Institute of Arctic and Alpine Research, University of Colorado, 1560 30th Street, Campus Box 450, Boulder, Colorado 80309 USA
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26
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Argerich A, Martí E, Sabater F, Ribot M. Temporal variation of hydrological exchange and hyporheic biogeochemistry in a headwater stream during autumn. ACTA ACUST UNITED AC 2011. [DOI: 10.1899/10-078.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alba Argerich
- Departament d’Ecologia, Universitat de Barcelona, Diagonal 645, Barcelona 08028, Spain
| | - Eugènia Martí
- Biogeodynamics and Biodiversity Group, Centre d’Estudis Avançats de Blanes (CSIC), Accés a la Cala St. Francesc 14, Blanes 17300, Girona, Spain
| | - Francesc Sabater
- Departament d’Ecologia, Universitat de Barcelona, Diagonal 645, Barcelona 08028, Spain
| | - Miquel Ribot
- Biogeodynamics and Biodiversity Group, Centre d’Estudis Avançats de Blanes (CSIC), Accés a la Cala St. Francesc 14, Blanes 17300, Girona, Spain
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Yagi JM, Suflita JM, Gieg LM, DeRito CM, Jeon CO, Madsen EL. Subsurface cycling of nitrogen and anaerobic aromatic hydrocarbon biodegradation revealed by nucleic Acid and metabolic biomarkers. Appl Environ Microbiol 2010; 76:3124-34. [PMID: 20348302 PMCID: PMC2869145 DOI: 10.1128/aem.00172-10] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2010] [Accepted: 03/17/2010] [Indexed: 11/20/2022] Open
Abstract
Microbial processes are crucial for ecosystem maintenance, yet documentation of these processes in complex open field sites is challenging. Here we used a multidisciplinary strategy (site geochemistry, laboratory biodegradation assays, and field extraction of molecular biomarkers) to deduce an ongoing linkage between aromatic hydrocarbon biodegradation and nitrogen cycling in a contaminated subsurface site. Three site wells were monitored over a 10-month period, which revealed fluctuating concentrations of nitrate, ammonia, sulfate, sulfide, methane, and other constituents. Biodegradation assays performed under multiple redox conditions indicated that naphthalene metabolism was favored under aerobic conditions. To explore in situ field processes, we measured metabolites of anaerobic naphthalene metabolism and expressed mRNA transcripts selected to document aerobic and anaerobic microbial transformations of ammonia, nitrate, and methylated aromatic contaminants. Gas chromatography-mass spectrometry detection of two carboxylated naphthalene metabolites and transcribed benzylsuccinate synthase, cytochrome c nitrite reductase, and ammonia monooxygenase genes indicated that anaerobic metabolism of aromatic compounds and both dissimilatory nitrate reduction to ammonia (DNRA) and nitrification occurred in situ. These data link formation (via DNRA) and destruction (via nitrification) of ammonia to in situ cycling of nitrogen in this subsurface habitat, where metabolism of aromatic pollutants has led to accumulation of reduced metabolic end products (e.g., ammonia and methane).
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Affiliation(s)
- Jane M. Yagi
- Department of Microbiology, Wing Hall, Cornell University, Ithaca, New York 14853, Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma 73109, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4, Chung-Ang University, Department of Life Science, 221 HeukSeok-Dong, Dongjak-Gu, Seoul 156-756, South Korea
| | - Joseph M. Suflita
- Department of Microbiology, Wing Hall, Cornell University, Ithaca, New York 14853, Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma 73109, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4, Chung-Ang University, Department of Life Science, 221 HeukSeok-Dong, Dongjak-Gu, Seoul 156-756, South Korea
| | - Lisa M. Gieg
- Department of Microbiology, Wing Hall, Cornell University, Ithaca, New York 14853, Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma 73109, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4, Chung-Ang University, Department of Life Science, 221 HeukSeok-Dong, Dongjak-Gu, Seoul 156-756, South Korea
| | - Christopher M. DeRito
- Department of Microbiology, Wing Hall, Cornell University, Ithaca, New York 14853, Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma 73109, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4, Chung-Ang University, Department of Life Science, 221 HeukSeok-Dong, Dongjak-Gu, Seoul 156-756, South Korea
| | - Che-Ok Jeon
- Department of Microbiology, Wing Hall, Cornell University, Ithaca, New York 14853, Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma 73109, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4, Chung-Ang University, Department of Life Science, 221 HeukSeok-Dong, Dongjak-Gu, Seoul 156-756, South Korea
| | - Eugene L. Madsen
- Department of Microbiology, Wing Hall, Cornell University, Ithaca, New York 14853, Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma 73109, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4, Chung-Ang University, Department of Life Science, 221 HeukSeok-Dong, Dongjak-Gu, Seoul 156-756, South Korea
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Mulholland PJ, Webster JR. Nutrient dynamics in streams and the role of J-NABS. ACTA ACUST UNITED AC 2010. [DOI: 10.1899/08-035.1] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Patrick J. Mulholland
- Environmental Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6036 USA
| | - Jackson R. Webster
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 USA
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Koch JC, McKnight DM, Baeseman JL. Effect of unsteady flow on nitrate loss in an oligotrophic, glacial meltwater stream. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jg001030] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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30
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31
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Landscape Distribution of Microbial Activity in the McMurdo Dry Valleys: Linked Biotic Processes, Hydrology, and Geochemistry in a Cold Desert Ecosystem. Ecosystems 2009. [DOI: 10.1007/s10021-009-9242-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Roberts BJ, Mulholland PJ. In-stream biotic control on nutrient biogeochemistry in a forested stream, West Fork of Walker Branch. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2007jg000422] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Brian J. Roberts
- Environmental Sciences Division; Oak Ridge National Laboratory; Oak Ridge Tennessee USA
| | - Patrick J. Mulholland
- Environmental Sciences Division; Oak Ridge National Laboratory; Oak Ridge Tennessee USA
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Barrett JE, Virginia RA, Lyons WB, McKnight DM, Priscu JC, Doran PT, Fountain AG, Wall DH, Moorhead DL. Biogeochemical stoichiometry of Antarctic Dry Valley ecosystems. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2005jg000141] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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