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Slate ML, Antoninka A, Bailey L, Berdugo MB, Callaghan DA, Cárdenas M, Chmielewski MW, Fenton NJ, Holland-Moritz H, Hopkins S, Jean M, Kraichak BE, Lindo Z, Merced A, Oke T, Stanton D, Stuart J, Tucker D, Coe KK. Impact of changing climate on bryophyte contributions to terrestrial water, carbon, and nitrogen cycles. THE NEW PHYTOLOGIST 2024; 242:2411-2429. [PMID: 38659154 DOI: 10.1111/nph.19772] [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: 12/20/2023] [Accepted: 03/22/2024] [Indexed: 04/26/2024]
Abstract
Bryophytes, including the lineages of mosses, liverworts, and hornworts, are the second-largest photoautotroph group on Earth. Recent work across terrestrial ecosystems has highlighted how bryophytes retain and control water, fix substantial amounts of carbon (C), and contribute to nitrogen (N) cycles in forests (boreal, temperate, and tropical), tundra, peatlands, grasslands, and deserts. Understanding how changing climate affects bryophyte contributions to global cycles in different ecosystems is of primary importance. However, because of their small physical size, bryophytes have been largely ignored in research on water, C, and N cycles at global scales. Here, we review the literature on how bryophytes influence global biogeochemical cycles, and we highlight that while some aspects of global change represent critical tipping points for survival, bryophytes may also buffer many ecosystems from change due to their capacity for water, C, and N uptake and storage. However, as the thresholds of resistance of bryophytes to temperature and precipitation regime changes are mostly unknown, it is challenging to predict how long this buffering capacity will remain functional. Furthermore, as ecosystems shift their global distribution in response to changing climate, the size of different bryophyte-influenced biomes will change, resulting in shifts in the magnitude of bryophyte impacts on global ecosystem functions.
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Affiliation(s)
- Mandy L Slate
- Department of Evolution, Ecology & Organismal Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Anita Antoninka
- School of Forestry, Northern Arizona University, Flagstaff, AZ, 86005, USA
| | - Lydia Bailey
- School of Forestry, Northern Arizona University, Flagstaff, AZ, 86005, USA
| | - Monica B Berdugo
- Plant Ecology and Geobotany, Department of Biology, University of Marburg, Karl-von-Frisch Str. 8, 35043, Marburg, Germany
| | - Des A Callaghan
- Bryophyte Surveys Ltd, Almondsbury, South Gloucestershire, BS32 4DU, UK
| | - Mariana Cárdenas
- Department of Ecology Evolution and Behavior, University of Minnesota, Saint Paul, MN, 55108, USA
| | | | - Nicole J Fenton
- Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, QC, J9X 5E4, Canada
| | - Hannah Holland-Moritz
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, 03824, USA
| | - Samantha Hopkins
- Department of Biology, University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Mélanie Jean
- Université de Moncton, Moncton, NB, E1A 3E9, Canada
| | - Bier Ekaphan Kraichak
- Department of Botany, Faculty of Science, Kasetsart University in Bangkok, Bangkok, 10900, Thailand
| | - Zoë Lindo
- Department of Biology, University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Amelia Merced
- Department of Biology, University of Puerto Rico Río Piedras, San Juan, PR, 00925, USA
| | - Tobi Oke
- Wildlife Conservation Society & School of Environment & Sustainability, University of Saskatchewan, Saskatoon, SK, S7N 5C8, Canada
| | - Daniel Stanton
- Department of Ecology Evolution and Behavior, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Julia Stuart
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI, 49931, USA
- Mountain Planning Service Group, US Forest Service, Lakewood, CO, 80401, USA
| | - Daniel Tucker
- School of Environmental Studies, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Kirsten K Coe
- Department of Biology, Middlebury College, Middlebury, VT, 05753, USA
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2
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Groß C, Hossen S, Dittrich S, Knorr KH, Borken W, Noll M. Biological nitrogen fixation, diversity and community structure of diazotrophs in two mosses in 25 temperate forests. Environ Microbiol 2024; 26:e16555. [PMID: 38148519 DOI: 10.1111/1462-2920.16555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 11/27/2023] [Indexed: 12/28/2023]
Abstract
Many moss species are associated with nitrogen (N)-fixing bacteria (diazotrophs) that support the N supply of mosses. Our knowledge relates primarily to pristine ecosystems with low atmospheric N input, but knowledge of biological N fixation (BNF) and diazotrophic communities in mosses in temperate forests with high N deposition is limited. We measured BNF rates using the direct stable isotope method and studied the total and potentially active diazotrophic communities in two abundant mosses, Brachythecium rutabulum and Hypnum cupressiforme, both growing on lying deadwood trunks in 25 temperate forest sites. BNF rates in both mosses were similar to those observed in moss species of pristine ecosystems. H. cupressiforme fixed three times more N2 and exhibited lower diazotrophic richness than B. rutabulum. Frankia was the most prominent diazotroph followed by cyanobacteria Nostoc. Manganese, iron, and molybdenum contents in mosses were positively correlated with BNF and diazotrophic communities. Frankia maintained high BNF rates in H. cupressiforme and B. rutabulum even under high chronic N deposition in Central European forests. Moss N concentration and 15 N abundance indicate a rather minor contribution of BNF to the N nutrition of these mosses.
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Affiliation(s)
- Christina Groß
- Department of Soil Ecology, University of Bayreuth, Bayreuth, Germany
| | - Shakhawat Hossen
- Institute for Bioanalysis, Coburg University of Applied Sciences and Arts, Coburg, Germany
| | - Sebastian Dittrich
- Biodiversity and Conservation, Technical University of Dresden, Tharandt, Germany
| | - Klaus-Holger Knorr
- Institute of Landscape Ecology, Ecohydrology and Biogeochemistry Group, University of Münster, Münster, Germany
| | - Werner Borken
- Department of Soil Ecology, University of Bayreuth, Bayreuth, Germany
| | - Matthias Noll
- Institute for Bioanalysis, Coburg University of Applied Sciences and Arts, Coburg, Germany
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3
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Yang Q, Liu Z, Bai E. Comparison of carbon and nitrogen accumulation rate between bog and fen phases in a pristine peatland with the fen-bog transition. GLOBAL CHANGE BIOLOGY 2023; 29:6350-6366. [PMID: 37602716 DOI: 10.1111/gcb.16915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023]
Abstract
Long-term carbon and nitrogen dynamics in peatlands are affected by both vegetation production and decomposition processes. Here, we examined the carbon accumulation rate (CAR), nitrogen accumulation rate (NAR) and δ13 C, δ15 N of plant residuals in a peat core dated back to ~8500 cal year BP in a temperate peatland in Northeast China. Impacted by the tephra during 1160 and 789 cal year BP and climate change, the peatland changed from a fen dominated by vascular plants to a bog dominated by Sphagnum mosses. We used the Clymo model to quantify peat addition rate and decay constant for acrotelm and catotelm layers during both bog and fen phases. Our studied peatland was dominated by Sphagnum fuscum during the bog phase (789 to -59 cal year BP) and lower accumulation rates in the acrotelm layer was found during this phase, suggesting the dominant role of volcanic eruption in the CAR of the peat core. Both mean CAR and NAR were higher during the bog phase than during the fen phase in our study, consistent with the results of the only one similar study in the literature. Because the input rate of organic matter was considered to be lower during the bog phase, the decomposition process must have been much lower during the bog phase than during the fen phase and potentially controlled CAR and NAR. During the fen phase, CAR was also lower under higher temperature and summer insolation, conditions beneficial for decomposition. δ15 N of Sphagnum hinted that nitrogen fixation had a positive effect on nitrogen accumulation, particular in recent decades. Our study suggested that decomposition is more important for carbon and nitrogen sequestration than production in peatlands in most conditions and if future climate changes or human disturbance increase decomposition rate, carbon sequestration in peatlands will be jeopardized.
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Affiliation(s)
- Qiannan Yang
- Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
| | - Ziping Liu
- Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun, China
| | - Edith Bai
- Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun, China
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Genome-Resolved Metagenomics Informs the Functional Ecology of Uncultured Acidobacteria in Redox Oscillated Sphagnum Peat. mSystems 2022; 7:e0005522. [PMID: 36036503 PMCID: PMC9599518 DOI: 10.1128/msystems.00055-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Understanding microbial niche differentiation along ecological and geochemical gradients is critical for assessing the mechanisms of ecosystem response to hydrologic variation and other aspects of global change. The lineage-specific biogeochemical roles of the widespread phylum Acidobacteria in hydrologically sensitive ecosystems, such as peatlands, are poorly understood. Here, we demonstrate that Acidobacteria sublineages in Sphagnum peat respond differentially to redox fluctuations due to variable oxygen (O2) availability, a typical feature of hydrologic variation. Our genome-centric approach disentangles the mechanisms of niche differentiation between the Acidobacteria genera Holophaga and Terracidiphilus in response to the transient O2 exposure of peat in laboratory incubations. Interlineage functional diversification explains the enrichment of the otherwise rare Holophaga in anoxic peat after transient O2 exposure in comparison to Terracidiphilus dominance in continuously anoxic peat. The observed niche differentiation of the two lineages is linked to differences in their carbon degradation potential. Holophaga appear to be primarily reliant on carbohydrate oligomers and amino acids, produced during the prior period of O2 exposure via the O2-stimulated breakdown of peat carbon, rich in complex aromatics and carbohydrate polymers. In contrast, Terracidiphilus genomes are enriched in diverse respiratory hydrogenases and carbohydrate active enzymes, enabling the degradation of complex plant polysaccharides into monomers and oligomers for fermentation. We also present the first evidence for the potential contribution of Acidobacteria in peat nitrogen fixation. In addition to canonical molybdenum-based diazotrophy, the Acidobacteria genomes harbor vanadium and iron-only alternative nitrogenases. Together, the results better inform the different functional roles of Acidobacteria in peat biogeochemistry under global change. IMPORTANCE Acidobacteria are among the most widespread and abundant members of the soil bacterial community, yet their ecophysiology remains largely underexplored. In acidic peat systems, Acidobacteria are thought to perform key biogeochemical functions, yet the mechanistic links between the phylogenetic and metabolic diversity within this phylum and peat carbon transformations remain unclear. Here, we employ genomic comparisons of Acidobacteria subgroups enriched in laboratory incubations of peat under variable O2 availability to disentangle the lineage-specific functional roles of these microorganisms in peat carbon transformations. Our genome-centric approach reveals that the diversification of Acidobacteria subpopulations across transient O2 exposure is linked to differences in their carbon substrate preferences. We also identify a previously unknown functional potential for biological nitrogen fixation in these organisms. This has important implications for carbon, nitrogen, and trace metal cycling in peat systems.
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Chen Q, Chen J, Andersen MN, Cheng X. Elevational shifts in foliar-soil δ 15 N in the Hengduan Mountains and different potential mechanisms. GLOBAL CHANGE BIOLOGY 2022; 28:5480-5491. [PMID: 35713965 DOI: 10.1111/gcb.16306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
The natural abundance of stable nitrogen isotopes (δ15 N) provides insights into the N dynamics of terrestrial ecosystems, the determination of which is considered an effective approach for gaining a better understanding ecosystem N cycling. However, there is currently little information available regarding the patterns and mechanisms underlying the variation in foliar-soil δ15 N among mountain ecosystems. In this study, we examined the determinants of foliar-soil δ15 N in association with N transportation rates along an elevational gradient in the Hengduan Mountains. Despite the relatively high levels of available N produced from high N fixation and mineralization, we detected the lowest levels of foliar δ15 N at 3500 m a.s.l., reflecting the stronger vegetation N limitation at medium high elevations. The enhanced vegetation N limitation was driven by the combined effects of higher microbial immobilization and inherent plant dynamic (the shifts of δ15 N in vegetation preference, including vegetation community) with changing climate along the elevational gradient. Unexpectedly, we established that soil δ15 N was characterized by an undulating rise and uncoupled correlation with foliar δ15 N with increasing elevation, thereby indicating that litter input might not be a prominent driver of soil δ15 N. Conversely, soil nitrification and denitrification were found to make a more pronounced contribution to the pattern of soil δ15 N along the elevational gradient. Collectively, our results serve to highlight the importance of microbial immobilization in soil N dynamics and provide novel insights that will contribute to enhancing our understanding of N cycling as indicated by foliar-soil δ15 N along elevational gradients.
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Affiliation(s)
- Qiong Chen
- Key Laboratory of Soil Ecology and Health in Universities of Yunnan Province, School of Ecology and Environmental Sciences, Yunnan University, Kunming, P.R. China
- Department of Agroecology, Aarhus University, Tjele, Denmark
| | - Ji Chen
- Department of Agroecology, Aarhus University, Tjele, Denmark
- Aarhus University Centre for Circular Bioeconomy, Aarhus University, Tjele, Denmark
- iCLIMATE Interdisciplinary Centre for Climate Change, Aarhus University, Roskilde, Denmark
| | - Mathias Neumann Andersen
- Department of Agroecology, Aarhus University, Tjele, Denmark
- Aarhus University Centre for Circular Bioeconomy, Aarhus University, Tjele, Denmark
- Sino-Danish Center for Education and Research, Eastern Yanqihu Campus, University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Xiaoli Cheng
- Key Laboratory of Soil Ecology and Health in Universities of Yunnan Province, School of Ecology and Environmental Sciences, Yunnan University, Kunming, P.R. China
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Klaes B, Wörner G, Thiele-Bruhn S, Arz HW, Struck J, Dellwig O, Groschopf N, Lorenz M, Wagner JF, Urrea OB, Lamy F, Kilian R. Element mobility related to rock weathering and soil formation at the westward side of the southernmost Patagonian Andes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 817:152977. [PMID: 35016939 DOI: 10.1016/j.scitotenv.2022.152977] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/25/2021] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
Rock weathering and pedogenesis are fundamental processes for element mobility in terrestrial bio-geochemical cycles and for the regulation of primary productivity in adjacent coastal marine ecosystems. Here, soils developed from volcanic ash under extreme climate conditions could play a particular role. We therefore investigated rock weathering, soil formation and the associated mobilization of trace elements and micronutrients in a pristine South Patagonian ecosystem. Weathered and unweathered basement lithologies, tephra of the 4.216 kyrs BP Mt. Burney eruption and four soil profiles are considered. The approach combines mineralogical (XRD, SEM) and inorganic geochemical (XRF, ICP-OES/MS) with organic geochemical analyses (TOC, TN, δ13C, δ15N, DOC extracts) of representative samples. Chemical weathering is quantified by mass balance calculations and 14C age constraints allow a correlation of pedogenic processes with the paleoenvironmental history of the area. Our data document that pedogenesis with initial peat formation occurred since ~2.5 kyrs BP. In these acidic peaty Andosols, intensive alteration of volcanic glass mobilized large quantities of elements, considerably surpassing leachates provided by basement rock weathering. Clay production is limited in favor of the formation of amorphous Al- and crystalline Fe-(hydr)oxides. However, tephra alteration, soil organic matter turnover rates, enhanced dissolved organic carbon export, and Fe-/Al-(hydr)oxide precipitation are closely linked and ultimately controlled by rainfall-induced water-level fluctuations, highlighting the dominant influence of the southern westerly wind belt. The transport of mobilized trace elements and micronutrients adsorbed onto suspended colloids (dissolved organic carbon, Al-humus complexes and Fe-(hydr)oxides) is redox-pH-dependent, highly variable and ultimately regulated by westerly intensity. Broader implications of this work include a new perspective on the climate-controlled micronutrient delivery for primary productivity in South Patagonian fjords, which is strongly affected by Andosol formation. Furthermore, a careful evaluation of 'ordinary' geochemical proxies in regional paleoenvironmental archives is needed to account for these unique pedogenic processes.
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Affiliation(s)
- Björn Klaes
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany; Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Gerhard Wörner
- Division of Geochemistry and Isotope Geology, GZG, Georg-August-University Göttingen, Goldschmidtstraße 1, 37077 Göttingen, Germany.
| | - Sören Thiele-Bruhn
- Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Helge Wolfgang Arz
- Marine Geology Department, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Seestraße 15, 18119 Rostock, Germany.
| | - Julian Struck
- Department of Physical Geography, Institute of Geography, Friedrich-Schiller-University Jena, Löbdergraben 32, 07743 Jena, Germany.
| | - Olaf Dellwig
- Marine Geology Department, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Seestraße 15, 18119 Rostock, Germany.
| | - Nora Groschopf
- Petrology Research Group, Institute of Geosciences, Johannes Gutenberg University Mainz, Johann-Joachim-Becher-Weg 21, 55128 Mainz, Germany.
| | - Marcel Lorenz
- Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Jean-Frank Wagner
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Oscar Baeza Urrea
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Frank Lamy
- Alfred Wegener Institute (AWI) Bremerhaven, Am Alten Hafen 26, 27568 Bremerhaven, Germany.
| | - Rolf Kilian
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany; University of Magallanes, Avenida Bulnes, 01855 Punta Arenas, Chile
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Schuster W, Knorr KH, Blodau C, Gałka M, Borken W, Pancotto VA, Kleinebecker T. Control of carbon and nitrogen accumulation by vegetation in pristine bogs of southern Patagonia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 810:151293. [PMID: 34756900 DOI: 10.1016/j.scitotenv.2021.151293] [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: 05/07/2021] [Revised: 10/22/2021] [Accepted: 10/24/2021] [Indexed: 06/13/2023]
Abstract
Peatlands are long-term sinks of carbon (C) and nitrogen (N) that are exposed to anthropogenic pressure. This has often induced a vegetation shift from peat mosses towards increasing presence of vascular plants. However, the impact of this vegetation shift on the sink function of peatlands remains unclear. To address this research gap, we studied C and N accumulation in a Patagonian cushion bog where a shift to the predominance of vascular cushion plants is a natural phenomenon since millennia. For comparison, long-term accumulation and decomposition patterns in a pristine Patagonian Sphagnum bog were studied. Thereto, we determined recent and long-term rates of C and N accumulation, their within-site variability, and studied plant-macrofossils. These results were related to decomposition indicators (C/N ratio, humification index, stable isotopes) of the bog types. Despite differences in decomposition indicators, long-term rates of C accumulation were of similar magnitude in the Sphagnum (21.9 g C m-2 yr-1) and in the cushion bog (22.2 g C m-2 yr-1). N accumulation was significantly lower in the Sphagnum bog (0.35 g N m-2 yr-1) compared to the surprisingly high accumulation in the cushion bog (0.55 g N m-2 yr-1). Tephra depositions in the cushion bog about 1600 cal. Years ago presumably triggered the vegetation shift towards dominance of cushion plants by a fertilization effect. C accumulation rates during past decades in the upper decimeters of peat were four times higher in the cushion bog (245 g C m-2 yr-1) compared to the Sphagnum bog (64 g C m-2 yr-1), but substantially decreased since the appearance of cushion plants. High decomposition rates as indicated by decomposition indicators thus apparently offset the higher productivity of cushion plants in the long term. While cushion bogs appear to be effective N sinks, their C sink function may therefore be equal to Sphagnum bogs.
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Affiliation(s)
- Wiebke Schuster
- Ecohydrology and Biogeochemistry Research Group, Institute of Landscape Ecology, University of Muenster, Heisenbergstr. 2, 48149 Muenster, Germany; Biodiversity and Ecosystem Research Group, Institute of Landscape Ecology, University of Muenster, Heisenbergstr. 2, 48149 Muenster, Germany
| | - Klaus-Holger Knorr
- Ecohydrology and Biogeochemistry Research Group, Institute of Landscape Ecology, University of Muenster, Heisenbergstr. 2, 48149 Muenster, Germany.
| | - Christian Blodau
- Ecohydrology and Biogeochemistry Research Group, Institute of Landscape Ecology, University of Muenster, Heisenbergstr. 2, 48149 Muenster, Germany
| | - Mariusz Gałka
- Biogeography, Paleoecology and Nature Conservation, Faculty of Biology and Environmental Protection, University of Lodz, 1/3 Banacha Str., 90-231 Lodz, Poland
| | - Werner Borken
- Department of Soil Ecology, Faculty of Biology, Chemistry and Geosciences, University of Bayreuth, Dr.-Hans-Frisch-Str. 1-3, 95448 Bayreuth, Germany
| | - Verónica A Pancotto
- Centro Austral de Investigaciones Científicas (CADIC-CONICET), B. Houssay 200, 9410 Ushuaia, Tierra del Fuego, Argentina; Instituto de Ciencias Polares y Ambiente (ICPA-UNTDF), Fuegia Basket, 9410 Ushuaia, Tierra del Fuego, Argentina
| | - Till Kleinebecker
- Biodiversity and Ecosystem Research Group, Institute of Landscape Ecology, University of Muenster, Heisenbergstr. 2, 48149 Muenster, Germany; Institute of Landscape Ecology and Resources Management, Giessen University, Heinrich-Buff-Ring 26, 35392 Gießen, Germany
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8
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Sgouridis F, Yates CA, Lloyd CEM, Saiz E, Schillereff DN, Tomlinson S, Williamson J, Ullah S. Chronic atmospheric reactive N deposition has breached the N sink capacity of a northern ombrotrophic peatbog increasing the gaseous and fluvial N losses. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 787:147552. [PMID: 34004537 DOI: 10.1016/j.scitotenv.2021.147552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/23/2021] [Accepted: 04/30/2021] [Indexed: 06/12/2023]
Abstract
Peatlands play an important role in modulating the climate, mainly through sequestration of carbon dioxide into peat carbon, which depends on the availability of reactive nitrogen (Nr) to mosses. Atmospheric Nr deposition in the UK has been above the critical load for functional and structural changes to peatland mosses, thus threatening to accelerate their succession by vascular plants and increasing the possibility of Nr export to downstream ecosystems. The N balance of peatlands has received comparatively little attention, mainly due to the difficulty in measuring gaseous N losses as well as the Nr inputs due to biological nitrogen fixation (BNF). In this study we have estimated the mean annual N balance of an ombrotrophic bog (Migneint, North Wales) by measuring in situ N2 + N2O gaseous fluxes and also BNF in peat and mosses. Fluvial N export was monitored through a continuous record of DON flux, while atmospheric N deposition was modelled on a 5 × 5 km grid. The mean annual N mass balance was slightly positive (0.7 ± 4.1 kg N ha-1 y-1) and varied interannually indicating the fragile status of this bog ecosystem that has reached N saturation and is prone to becoming a net N source. Gaseous N losses were a major N output term accounting for 70% of the N inputs, mainly in the form of the inert N2 gas, thus providing partial mitigation to the adverse effects of chronic Nr enrichment. BNF was suppressed by 69%, compared to rates in pristine bogs, but was still active, contributing ~2% of the N inputs. The long-term peat N storage rate (8.4 ± 0.8 kg N ha-1 y-1) cannot be met by the measured N mass balance, showing that the bog catchment is losing more N than it can store due its saturated status.
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Affiliation(s)
| | | | | | - Ernesto Saiz
- Lennard-Jones Laboratories, Birchall Centre, Keele University, UK
| | | | - Sam Tomlinson
- UK Centre for Ecology & Hydrology (UKCEH), Lancaster, UK
| | | | - Sami Ullah
- Department of Geography, Earth and Environmental Science, University of Birmingham, UK
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9
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Saiz E, Sgouridis F, Drijfhout FP, Peichl M, Nilsson MB, Ullah S. Chronic Atmospheric Reactive Nitrogen Deposition Suppresses Biological Nitrogen Fixation in Peatlands. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:1310-1318. [PMID: 33389989 DOI: 10.1021/acs.est.0c04882] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Biological nitrogen fixation (BNF) represents the natural pathway by which mosses meet their demands for bioavailable/reactive nitrogen (Nr) in peatlands. However, following intensification of nitrogen fertilizer and fossil fuel use, atmospheric Nr deposition has increased exposing peatlands to Nr loading often above the ecological threshold. As BNF is energy intensive, therefore, it is unclear whether BNF shuts down when Nr availability is no longer a rarity. We studied the response of BNF under a gradient of Nr deposition extending over decades in three peatlands in the U.K., and at a background deposition peatland in Sweden. Experimental nitrogen fertilization plots in the Swedish site were also evaluated for BNF activity. In situ BNF activity of peatlands receiving Nr deposition of 6, 17, and 27 kg N ha-1 yr-1 was not shut down but rather suppressed by 54, 69, and 74%, respectively, compared to the rates under background Nr deposition of ∼2 kg N ha-1 yr-1. These findings were corroborated by similar BNF suppression at the fertilization plots in Sweden. Therefore, contribution of BNF in peatlands exposed to chronic Nr deposition needs accounting when modeling peatland's nitrogen pools, given that nitrogen availability exerts a key control on the carbon capture of peatlands, globally.
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Affiliation(s)
- Ernesto Saiz
- School of Geography, Geology, and the Environment, Keele University, Staffordshire ST5 5BG, United Kingdom
| | - Fotis Sgouridis
- School of Geographical Sciences, University of Bristol, Bristol BS8 1SS, United Kingdom
| | - Falko P Drijfhout
- Chemical Ecology Group, School of Physical and Chemical Sciences, Keele University, Staffordshire ST5 5BG, United Kingdom
| | - Matthias Peichl
- Department of Forest Ecology & Management, Swedish University of Agricultural Sciences, Umeå 750 07, Sweden
| | - Mats B Nilsson
- Department of Forest Ecology & Management, Swedish University of Agricultural Sciences, Umeå 750 07, Sweden
| | - Sami Ullah
- School of Geography, Earth, and Environmental Sciences, and Birmingham Institute of Forest Research, University of Birmingham, Birmingham B15 2TT, United Kingdom
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Zhang X, Jia X, Wu H, Li J, Yan L, Wang J, Li Y, Kang X. Depression of soil nitrogen fixation by drying soil in a degraded alpine peatland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 747:141084. [PMID: 32771776 DOI: 10.1016/j.scitotenv.2020.141084] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 07/16/2020] [Accepted: 07/18/2020] [Indexed: 06/11/2023]
Abstract
Soil biological nitrogen fixation (BNF) represents a major pathway through which nitrogen enters pristine peatlands. Many peatlands have been undergoing human-induced changes in environmental factors, while environmental changes dramatically affect the community composition and activity of nitrogen-fixing prokaryotes (i.e., diazotrophs). However, the impact of peatland degradation on soil BNF remains unclear. By carrying out a field campaign, we examined how soil BNF varies along a natural gradient from pristine marshes to moderately-degraded meadows and sandy meadows on the Zoige Plateau. Plant and topsoil samples from four pristine marshes, three moderately-degraded meadows, and three sandy meadows were collected to determine the potential rate of nitrogen fixation (RNfix), abundance of the nifH gene, diazotrophic community composition, and soil and plant characteristics. Our results showed that topsoil RNfix varied in the range 0.018-3.00 μmol N g d.w.-1 day-1 (i.e. 21.74-1632.37 mg N m-2 day-1) across the ten sites, being lowest in sandy meadows and highest in pristine marshes. Topsoil RNfix and diazotrophic abundance were positively correlated with soil water content, sedge cover, plant biomass, soil organic carbon content, and total nitrogen and phosphorus contents. Soil water content, which affected most plant and soil characteristics, had dominant influences on the abundance and community structure of diazotrophs. The RNfix was closely correlated with the abundance of dominant diazotroph groups. The community composition of diazotrophs differed markedly among sites of different degradation levels. Proteobacteria was the most abundant diazotrophic phylum across the ten sites. Heterotrophic diazotrophs acted as the major contributor to BNF, especially in pristine marshes and moderately-degraded meadows. We conclude that soil water content was the main factor driving the depressed soil BNF during peatland degradation in Zoige, due to soil water effects on plant cover and biomass, soil organic carbon and total phosphorus, and the abundance and community structure of diazotrophs.
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Affiliation(s)
- Xiaodong Zhang
- Beijing Key Laboratory of Wetland Services and Restoration, Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China; Sichuan Zoige Wetland Ecosystem Research Station, Tibetan Autonomous Prefecture of Aba 624500, China
| | - Xin Jia
- Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
| | - Haidong Wu
- Beijing Key Laboratory of Wetland Services and Restoration, Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China; Sichuan Zoige Wetland Ecosystem Research Station, Tibetan Autonomous Prefecture of Aba 624500, China
| | - Jing Li
- Beijing Key Laboratory of Wetland Services and Restoration, Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China
| | - Liang Yan
- Beijing Key Laboratory of Wetland Services and Restoration, Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China; Sichuan Zoige Wetland Ecosystem Research Station, Tibetan Autonomous Prefecture of Aba 624500, China
| | - Jinzhi Wang
- Beijing Key Laboratory of Wetland Services and Restoration, Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China; Sichuan Zoige Wetland Ecosystem Research Station, Tibetan Autonomous Prefecture of Aba 624500, China
| | - Yong Li
- Beijing Key Laboratory of Wetland Services and Restoration, Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China; Sichuan Zoige Wetland Ecosystem Research Station, Tibetan Autonomous Prefecture of Aba 624500, China
| | - Xiaoming Kang
- Beijing Key Laboratory of Wetland Services and Restoration, Institute of Wetland Research, Chinese Academy of Forestry, Beijing 100091, China; Sichuan Zoige Wetland Ecosystem Research Station, Tibetan Autonomous Prefecture of Aba 624500, China.
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Mathijssen PJH, Gałka M, Borken W, Knorr KH. Plant communities control long term carbon accumulation and biogeochemical gradients in a Patagonian bog. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 684:670-681. [PMID: 31158628 DOI: 10.1016/j.scitotenv.2019.05.310] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/17/2019] [Accepted: 05/20/2019] [Indexed: 06/09/2023]
Abstract
Peat carbon accumulation is controlled by both large scale factors, such as climate and hydrological setting, and small scale factors, such as microtopography and plant community. These small scale factors commonly vary within peatlands and can cause variation in biogeochemical traits and carbon accumulation within the same site. To understand these within-site variations, we investigated long term carbon accumulation, peat decomposition, biogeochemistry of pore water and plant macrofossils along a transect in an ombrotrophic bog in southern Patagonia. An additional question we addressed is how historical deposition of volcanic ash on the peatland has affected its carbon balance. Variability in plant community and water table led to differences in long term peat and carbon accumulation (peat moss > cushion plant), organic matter decomposition (cushion plant > peat moss), and methane production (peat moss > cushion plant). Macrofossil analysis and radiocarbon dating indicated a relationship between plant community and carbon accumulation or decomposition during the historical succession of vegetation in the peatland. C/N ratio and isotopic signatures reflected variability in plant community as litter source, and DOC concentrations were controlled by humification level. Volcanic ash deposition had only limited effect on plant composition, but it was associated with increased decomposition in overlying peat layers. This study highlights the importance of understanding how plant communities develop, as changes in communities could significantly affect the potential of ombrotrophic peatlands as C sink.
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Affiliation(s)
- Paul J H Mathijssen
- WWU Münster, Institute of Landscape Ecology, Ecohydrology and Biogeochemistry Group, Heisenbergstr. 2, 48149 Münster, Germany.
| | - Mariusz Gałka
- Department of Geobotany and Plant Ecology, Faculty of Biology and Environmental Protection, University of Lodz, 12/16 Banacha Str., Lodz, Poland
| | - Werner Borken
- University of Bayreuth, Dept. of Soil Ecology, Dr.-Hans-Frisch-Str. 1-3, 95448 Bayreuth, Germany
| | - Klaus-Holger Knorr
- WWU Münster, Institute of Landscape Ecology, Ecohydrology and Biogeochemistry Group, Heisenbergstr. 2, 48149 Münster, Germany.
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12
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Novak M, Vile MA, Curik J, Cejkova B, Barta J, Stepanova M, Jackova I, Buzek F, Bohdalkova L, Prechova E, Veselovsky F, Adamova M, Valkova I, Komarek A. Retraction Statement: Comparison of nitrogen inputs and accumulation in 210 Pb-dated peat cores: Evidence for biological N 2 -fixation in Central European peatlands despite decades of atmospheric N pollution. GLOBAL CHANGE BIOLOGY 2019; 25:1547. [PMID: 30375707 DOI: 10.1111/gcb.14505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/10/2018] [Accepted: 10/08/2018] [Indexed: 06/08/2023]
Abstract
"Comparison of nitrogen inputs and accumulation in 210 Pb-dated peat cores: Evidence for biological N2 -fixation in Central European peatlands despite decades of atmospheric N pollution" https://doi.org/10.1111/gcb.14505, by Martin Novak, Melanie A. Vile, Jan Curik, Bohuslava Cejkova, Jiri Barta, Marketa Stepanova, Ivana Jackova, Frantisek Buzek, Leona Bohdalkova, Eva Prechova, Frantisek Veselovsky, Marie Adamova, Ivana Valkova and Arnost Komarek. The above article, first published online in Wiley Online Library (wileyonlinelibrary.com) in Global Change Biology, has been retracted by agreement between the authors, the journal Editor-in-Chief, Stephen P. Long, and John Wiley & Sons Ltd. Since publication of the above article, it was brought to the attention of the authors that the peat accretion rates violate reasonable ranges of peatland C/N/P stoichiometry, placing the quantitative conclusions of the article in serious error. The authors apologize for any inconvenience the publication of this work may have caused our readers. REFERENCE Novak, M., Vile, M. A., Cejkova, B., Barta, J., Stepanova, M., Jackova, I., Buzek, F., Bohdalkova, L., Prechova, E., Veselovsky, F., Adamova, M., Valkova, I., & Komarek, A. (2018). Comparison of nitrogen inputs and accumulation in 210 Pb-dated peat cores: Evidence for biological N2 -fixation in Central European peatlands despite decades of atmospheric N pollution. Global Change Biology.. https://doi.org/10.1111/gcb.14505.
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Affiliation(s)
- Martin Novak
- Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Melanie A Vile
- Department of Geography and the Environment, Villanova University, Villanova, Pennsylvania
| | - Jan Curik
- Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Bohuslava Cejkova
- Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Jiri Barta
- Department of Ecosystems Biology, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Marketa Stepanova
- Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Ivana Jackova
- Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Frantisek Buzek
- Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Leona Bohdalkova
- Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Eva Prechova
- Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Frantisek Veselovsky
- Department of High-temperature Geochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Marie Adamova
- Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Ivana Valkova
- Department of Environmental Geochemistry and Biogeochemistry, Czech Geological Survey, Prague 5, Czech Republic
| | - Arnost Komarek
- Faculty of Mathematics and Physics, Charles University, Prague 8, Czech Republic
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Novak M, Pacherova P, Elliott EM, Jackova I, Stepanova M, Curik J, Cejkova B, Buzek F, Prechova E, Valkova I. δ15N systematics in two minerotrophic peatlands in the eastern U.S.: Insights into nitrogen cycling under moderate pollution. Glob Ecol Conserv 2019. [DOI: 10.1016/j.gecco.2019.e00571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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14
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Benbow ME, Barton PS, Ulyshen MD, Beasley JC, DeVault TL, Strickland MS, Tomberlin JK, Jordan HR, Pechal JL. Necrobiome framework for bridging decomposition ecology of autotrophically and heterotrophically derived organic matter. ECOL MONOGR 2018. [DOI: 10.1002/ecm.1331] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- M. Eric Benbow
- Department of Entomology; Michigan State University; East Lansing Michigan 48824 USA
- Department of Osteopathic Medical Specialties; Michigan State University; East Lansing Michigan 48824 USA
- Ecology, Evolutionary Biology and Behavior Program; Michigan State University; East Lansing Michigan 48824 USA
| | - Philip S. Barton
- Fenner School of Environment and Society; Australian National University; Canberra Australian Capital Territory 2601 Australia
| | | | - James C. Beasley
- Savannah River Ecology Laboratory and Warnell School of Forestry and Natural Resources; University of Georgia; Aiken South Carolina 29802 USA
| | - Travis L. DeVault
- U.S. Department of Agriculture; National Wildlife Research Center; Sandusky Ohio 44870 USA
| | | | | | - Heather R. Jordan
- Department of Biological Sciences; Mississippi State University; Mississippi Mississippi 39762 USA
| | - Jennifer L. Pechal
- Department of Entomology; Michigan State University; East Lansing Michigan 48824 USA
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Kox MAR, Aalto SL, Penttilä T, Ettwig KF, Jetten MSM, van Kessel MAHJ. The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses. AMB Express 2018; 8:76. [PMID: 29730829 PMCID: PMC5936483 DOI: 10.1186/s13568-018-0607-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 04/28/2018] [Indexed: 11/10/2022] Open
Abstract
Biological nitrogen fixation is an important source of bioavailable nitrogen in Sphagnum dominated peatlands. Sphagnum mosses harbor a diverse microbiome including nitrogen-fixing and methane (CH4) oxidizing bacteria. The inhibitory effect of oxygen on microbial nitrogen fixation is documented for many bacteria. However, the role of nitrogen-fixing methanotrophs in nitrogen supply to Sphagnum peat mosses is not well explored. Here, we investigated the role of both oxygen and methane on nitrogen fixation in subarctic Sphagnum peat mosses. Five species of Sphagnum mosses were sampled from two mesotrophic and three oligotrophic sites within the Lakkasuo peatland in Orivesi, central Finland. Mosses were incubated under either ambient or low oxygen conditions in the presence or absence of methane. Stable isotope activity assays revealed considerable nitrogen-fixing and methane-assimilating rates at all sites (1.4 ± 0.2 µmol 15N-N2 g-1 DW day-1 and 12.0 ± 1.1 µmol 13C-CH4 g-1 DW day-1, respectively). Addition of methane did not stimulate incorporation of 15N-nitrogen into biomass, whereas oxygen depletion increased the activity of the nitrogen-fixing community. Analysis of the 16S rRNA genes at the bacterial community level showed a very diverse microbiome that was dominated by Alphaproteobacteria in all sites. Bona fide methane-oxidizing taxa were not very abundant (relative abundance less than 0.1%). Based on our results we conclude that methanotrophs did not contribute significantly to nitrogen fixation in the investigated peatlands.
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Affiliation(s)
- Martine A. R. Kox
- Department of Microbiology, Radboud University, Nijmegen, The Netherlands
| | - Sanni L. Aalto
- Department of Biological and Environmental Science, University of Jyväskylä, PO Box 35, 40014 Jyväskylä, Finland
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 1627, 70211 Kuopio, Finland
| | - Timo Penttilä
- Natural Resources Institute Finland, PO Box 2, 00791 Helsinki, Finland
| | | | - Mike S. M. Jetten
- Department of Microbiology, Radboud University, Nijmegen, The Netherlands
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Welz PJ, Ramond JB, Braun L, Vikram S, Le Roes-Hill M. Bacterial nitrogen fixation in sand bioreactors treating winery wastewater with a high carbon to nitrogen ratio. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 207:192-202. [PMID: 29179109 DOI: 10.1016/j.jenvman.2017.11.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 10/20/2017] [Accepted: 11/05/2017] [Indexed: 06/07/2023]
Abstract
Heterotrophic bacteria proliferate in organic-rich environments and systems containing sufficient essential nutrients. Nitrogen, phosphorus and potassium are the nutrients required in the highest concentrations. The ratio of carbon to nitrogen is an important consideration for wastewater bioremediation because insufficient nitrogen may result in decreased treatment efficiency. It has been shown that during the treatment of effluent from the pulp and paper industry, bacterial nitrogen fixation can supplement the nitrogen requirements of suspended growth systems. This study was conducted using physicochemical analyses and culture-dependent and -independent techniques to ascertain whether nitrogen-fixing bacteria were selected in biological sand filters used to treat synthetic winery wastewater with a high carbon to nitrogen ratio (193:1). The systems performed well, with the influent COD of 1351 mg/L being reduced by 84-89%. It was shown that the nitrogen fixing bacterial population was influenced by the presence of synthetic winery effluent in the surface layers of the biological sand filters, but not in the deeper layers. It was hypothesised that this was due to the greater availability of atmospheric nitrogen at the surface. The numbers of culture-able nitrogen-fixing bacteria, including presumptive Azotobacter spp. exhibited 1-2 log increases at the surface. The results of this study confirm that nitrogen fixation is an important mechanism to be considered during treatment of high carbon to nitrogen wastewater. If biological treatment systems can be operated to stimulate this phenomenon, it may obviate the need for nitrogen addition.
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Affiliation(s)
- Pamela J Welz
- Biocatalysis and Technical Biology Research Group, Institute for Medical and Microbial Biotechnology, Cape Peninsula University of Technology, Cape Town, South Africa.
| | - Jean-Baptiste Ramond
- Centre for Microbial Ecology and Genomics, Department of Genetics, University of Pretoria, Pretoria, South Africa
| | - Lorenz Braun
- Biocatalysis and Technical Biology Research Group, Institute for Medical and Microbial Biotechnology, Cape Peninsula University of Technology, Cape Town, South Africa
| | - Surendra Vikram
- Centre for Microbial Ecology and Genomics, Department of Genetics, University of Pretoria, Pretoria, South Africa
| | - Marilize Le Roes-Hill
- Biocatalysis and Technical Biology Research Group, Institute for Medical and Microbial Biotechnology, Cape Peninsula University of Technology, Cape Town, South Africa
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8000-year monsoonal record from Himalaya revealing reinforcement of tropical and global climate systems since mid-Holocene. Sci Rep 2017; 7:14515. [PMID: 29109454 PMCID: PMC5674060 DOI: 10.1038/s41598-017-15143-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 10/19/2017] [Indexed: 11/08/2022] Open
Abstract
We provide the first continuous Indian Summer Monsoon (ISM) climate record for the higher Himalayas (Kedarnath, India) by analyzing a 14C-dated peat sequence covering the last ~8000 years, with ~50 years temporal resolution. The ISM variability inferred using various proxies reveal striking similarity with the Greenland ice core (GISP2) temperature record and rapid denitrification changes recorded in the sediments off Peru. The Kedarnath record provides compelling evidence for a reorganization of the global climate system taking place at ~5.5 ka BP possibly after sea level stabilization and the advent of inter-annual climate variability governed by the modern ENSO phenomenon. The ISM record also captures warm-wet and cold-dry conditions during the Medieval Climate Anomaly and Little Ice Age, respectively.
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Molybdenum-Based Diazotrophy in a Sphagnum Peatland in Northern Minnesota. Appl Environ Microbiol 2017; 83:AEM.01174-17. [PMID: 28667112 DOI: 10.1128/aem.01174-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 06/28/2017] [Indexed: 11/20/2022] Open
Abstract
Microbial N2 fixation (diazotrophy) represents an important nitrogen source to oligotrophic peatland ecosystems, which are important sinks for atmospheric CO2 and are susceptible to the changing climate. The objectives of this study were (i) to determine the active microbial group and type of nitrogenase mediating diazotrophy in an ombrotrophic Sphagnum-dominated peat bog (the S1 peat bog, Marcell Experimental Forest, Minnesota, USA); and (ii) to determine the effect of environmental parameters (light, O2, CO2, and CH4) on potential rates of diazotrophy measured by acetylene (C2H2) reduction and 15N2 incorporation. A molecular analysis of metabolically active microbial communities suggested that diazotrophy in surface peat was primarily mediated by Alphaproteobacteria (Bradyrhizobiaceae and Beijerinckiaceae). Despite higher concentrations of dissolved vanadium ([V] 11 nM) than molybdenum ([Mo] 3 nM) in surface peat, a combination of metagenomic, amplicon sequencing, and activity measurements indicated that Mo-containing nitrogenases dominate over the V-containing form. Acetylene reduction was only detected in surface peat exposed to light, with the highest rates observed in peat collected from hollows with the highest water contents. Incorporation of 15N2 was suppressed 90% by O2 and 55% by C2H2 and was unaffected by CH4 and CO2 amendments. These results suggest that peatland diazotrophy is mediated by a combination of C2H2-sensitive and C2H2-insensitive microbes that are more active at low concentrations of O2 and show similar activity at high and low concentrations of CH4 IMPORTANCE Previous studies indicate that diazotrophy provides an important nitrogen source and is linked to methanotrophy in Sphagnum-dominated peatlands. However, the environmental controls and enzymatic pathways of peatland diazotrophy, as well as the metabolically active microbial populations that catalyze this process, remain in question. Our findings indicate that oxygen levels and photosynthetic activity override low nutrient availability in limiting diazotrophy and that members of the Alphaproteobacteria (Rhizobiales) catalyze this process at the bog surface using the molybdenum-based form of the nitrogenase enzyme.
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Borken W, Horn MA, Geimer S, Aguilar NAB, Knorr KH. Associative nitrogen fixation in nodules of the conifer Lepidothamnus fonkii (Podocarpaceae) inhabiting ombrotrophic bogs in southern Patagonia. Sci Rep 2016; 6:39072. [PMID: 27976730 PMCID: PMC5157042 DOI: 10.1038/srep39072] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 11/17/2016] [Indexed: 02/01/2023] Open
Abstract
Biological N2 fixation (BNF) in the rhizosphere of Podocarpaceae is currently attributed to unspecific diazotrophs with negligible impact on N acquisition. Here, we report specific and high associative BNF in dead cells of root nodules of Lepidothamnus fonkii distributed in ombrotrophic peatlands of Patagonia. BNF of nodulated roots, intact plants of L. fonkii and rhizospheric peat was assessed by 15N2 and acetylene reduction. Diazotrophs were identified by electron microscopy, analysis of nitrogenase encoding genes (nifH) and transcripts, and 16S rRNA. Nitrogenase encoding nifH transcripts from root nodules point to Beijerinckiaceae (Rhizobiales), known as free-living diazotrophs. Electron microscopy and 16S rRNA analysis likewise identified active Beijerinckiaceae in outer dead cells of root nodules. NifH transcripts from the rhizopshere peat revealed diverse active diazotrophs including Beijerinckiaceae. Both methods revealed high activity of nitrogenase rates in cut roots of L. fonkii (2.5 μmol N g-1 d.w. d-1 based on 15N2 assay; 2.4 μmol C2H4 g-1 d.w. d-1 based on acetylene reduction assay). The data suggest that (i) nodules recruit diazotrophic Beijerinckiaceae from peat, (ii) dead nodule cells provide an exclusive habitat for Beijerinckiaceae, and (iii) BNF in L. fonkii is one potent pathway to overcome N deficiency in ombrotrophic peatlands of Patagonia.
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Affiliation(s)
- Werner Borken
- University of Bayreuth, Department of Soil Ecology, Dr.-Hans-Frisch-Str. 1-3, 95448 Bayreuth, Germany
| | - Marcus A. Horn
- University of Bayreuth, Ecological Microbiology, Dr.-Hans-Frisch-Str. 1-3, 95448 Bayreuth, Germany
- University of Hannover, Institute of Microbiology, Herrenhäuserstr. 2, 30140 Hannover, Germany
| | - Stefan Geimer
- University of Bayreuth, Cell Biology and Electron Microscopy, Universitätsstr, 30, 95440 Bayreuth, Germany
| | - Nelson A. Bahamonde Aguilar
- Universidad de Magellanes, Instituto de la Patagonia, Laboratorio de Botanica, Av. Manuel Bulnes 01890, Punta Arenas, Chile
- ONG AMA Torres del Paine, Estancia Cerro Paine S/N, Torres del Payne, Chile
| | - Klaus-Holger Knorr
- University of Münster, ILÖK, Hydrology group, Heisenbergstr, 2, 48149, Münster, Germany
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Schillereff DN, Boyle JF, Toberman H, Adams JL, Bryant CL, Chiverrell RC, Helliwell RC, Keenan P, Lilly A, Tipping E. Long-term macronutrient stoichiometry of UK ombrotrophic peatlands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 572:1561-1572. [PMID: 27093906 DOI: 10.1016/j.scitotenv.2016.03.180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/24/2016] [Accepted: 03/24/2016] [Indexed: 06/05/2023]
Abstract
In this paper we report new data on peat carbon (C), nitrogen (N) and phosphorus (P) concentrations and accumulation rates for 15 sites in the UK. Concentrations of C, N and P measured in peat from five ombrotrophic blanket mires, spanning 4000-10,000years to present were combined with existing nutrient data from ten Scottish ombrotrophic peat bogs to provide the first UK perspective on millennial scale macronutrient concentrations in ombrotrophic peats. Long-term average C, N and P concentrations (0-1.25m) for the UK are 54.8, 1.56 and 0.039wt%, of similar magnitude to the few published comparable sites worldwide. The uppermost peat (0-0.2m) is enriched in P and N (51.0, 1.86, and 0.070wt%) relative to the deeper peat (0.5-1.25m, 56.3, 1.39, and 0.027wt%). Long-term average (whole core) accumulation rates of C, N and P are 25.3±2.2gCm-2year-1 (mean±SE), 0.70±0.09gNm-2year-1 and 0.018±0.004gPm-2year-1, again similar to values reported elsewhere in the world. The two most significant findings are: 1) that a regression model of N concentration on P concentration and mean annual precipitation, based on global meta data for surface peat samples, can explain 54% of variance in N concentration in these UK peat profiles; and 2) budget calculations for the UK peat cores yield an estimate for long-term average N-fixation of 0.8gm-2year-1. Our UK results, and comparison with others sites, corroborate published estimates of N storage in northern boreal peatlands through the Holocene as ranging between 8 and 15Pg N. However, the observed correlation of N% with both mean annual precipitation and P concentration allows a potential bias in global estimates that do not take this into account. The peat sampling data set has been deposited at the NERC Data Centre (Toberman et al., 2016).
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Affiliation(s)
- Daniel N Schillereff
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, United Kingdom.
| | - John F Boyle
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, United Kingdom.
| | - Hannah Toberman
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, United Kingdom.
| | - Jessica L Adams
- Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster LA1 4AP, United Kingdom.
| | - Charlotte L Bryant
- NERC Radiocarbon Facility (East Kilbride), Scottish Enterprise Technology Park, Rankine Avenue, East Kilbride, Scotland G75 OQF, United Kingdom.
| | - Richard C Chiverrell
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, United Kingdom.
| | - Rachel C Helliwell
- The James Hutton Institute, Craigiebuckler, Aberdeen, Scotland AB15 8QH, United Kingdom.
| | - Patrick Keenan
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom.
| | - Allan Lilly
- The James Hutton Institute, Craigiebuckler, Aberdeen, Scotland AB15 8QH, United Kingdom.
| | - Edward Tipping
- Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster LA1 4AP, United Kingdom.
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