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Hu Y, Chen J, Olesen JE, van Groenigen KJ, Hui D, He X, Chen G, Deng Q. Mycorrhizal association controls soil carbon-degrading enzyme activities and soil carbon dynamics under nitrogen addition: A systematic review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 948:175008. [PMID: 39053526 DOI: 10.1016/j.scitotenv.2024.175008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 07/16/2024] [Accepted: 07/22/2024] [Indexed: 07/27/2024]
Abstract
Recent evidence suggests that changes in carbon-degrading extracellular enzyme activities (C-EEAs) can help explain soil organic carbon (SOC) dynamics under nitrogen (N) addition. However, the factors controlling C-EEAs remain unclear, impeding the inclusion of microbial mechanisms in global C cycle models. Using meta-analysis, we show that the responses of C-EEAs to N addition were best explained by mycorrhizal association across a wide range of environmental and experimental factors. In ectomycorrhizal (ECM) dominated ecosystems, N addition suppressed C-EEAs targeting the decomposition of structurally complex macromolecules by 13.1 %, and increased SOC stocks by 5.2 %. In contrast, N addition did not affect C-EEAs and SOC stocks in arbuscular mycorrhizal (AM) dominated ecosystems. Our results indicate that earlier studies may have overestimated SOC changes under N addition in AM-dominated ecosystems and underestimated SOC changes in ECM-dominated ecosystems. Incorporating this mycorrhizal-dependent impact of EEAs on SOC dynamics into Earth system models could improve predictions of SOC dynamics under environmental changes.
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Affiliation(s)
- Yuanliu Hu
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong 510650, China; South China National Botanical Garden, Guangzhou, Guangdong 510650, China; University of Chinese Academy of Sciences, Beijing 100039, China; Department of Agroecology, Aarhus University, 8830 Tjele, Denmark
| | - Ji Chen
- Department of Agroecology, Aarhus University, 8830 Tjele, Denmark; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, 710001 Xi'an, China; Institute of Global Environmental Change, Department of Earth & Environmental Science, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi Province 710049, China.
| | - Jørgen E Olesen
- Department of Agroecology, Aarhus University, 8830 Tjele, Denmark; Aarhus University Centre for Circular Bioeconomy, Aarhus University, 8830 Tjele, Denmark
| | - Kees Jan van Groenigen
- Department of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Dafeng Hui
- Department of Biological Sciences, Tennessee State University, Nashville, TN 37209, USA
| | - Xinhua He
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creation in Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing 400715, China; School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
| | - Guoyin Chen
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong 510650, China; South China National Botanical Garden, Guangzhou, Guangdong 510650, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Qi Deng
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, Guangdong 510650, China; South China National Botanical Garden, Guangzhou, Guangdong 510650, China.
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2
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Jörgensen K, Clemmensen KE, Wallander H, Lindahl BD. Ectomycorrhizal fungi are more sensitive to high soil nitrogen levels in forests exposed to nitrogen deposition. THE NEW PHYTOLOGIST 2024; 242:1725-1738. [PMID: 38213001 DOI: 10.1111/nph.19509] [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: 09/18/2023] [Accepted: 12/11/2023] [Indexed: 01/13/2024]
Abstract
Ectomycorrhizal fungi are essential for nitrogen (N) cycling in many temperate forests and responsive to anthropogenic N addition, which generally decreases host carbon (C) allocation to the fungi. In the boreal region, however, ectomycorrhizal fungal biomass has been found to correlate positively with soil N availability. Still, responses to anthropogenic N input, for instance through atmospheric deposition, are commonly negative. To elucidate whether variation in N supply affects ectomycorrhizal fungi differently depending on geographical context, we investigated ectomycorrhizal fungal communities along fertility gradients located in two nemo-boreal forest regions with similar ranges in soil N : C ratios and inorganic N availability but contrasting rates of N deposition. Ectomycorrhizal biomass and community composition remained relatively stable across the N gradient with low atmospheric N deposition, but biomass decreased and the community changed more drastically with increasing N availability in the gradient subjected to higher rates of N deposition. Moreover, potential activities of enzymes involved in ectomycorrhizal mobilisation of organic N decreased as N availability increased. In forests with low external input, we propose that stabilising feedbacks in tree-fungal interactions maintain ectomycorrhizal fungal biomass and communities even in N-rich soils. By contrast, anthropogenic N input seems to impair ectomycorrhizal functions.
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Affiliation(s)
- Karolina Jörgensen
- Department of Soil and Environment, Swedish University of Agricultural Sciences, Box 7014, SE-750 07, Uppsala, Sweden
| | - Karina E Clemmensen
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, SE-750 07, Uppsala, Sweden
| | - Håkan Wallander
- Department of Biology, Lund University, Sölvegatan 37, 223 26, Lund, Sweden
| | - Björn D Lindahl
- Department of Soil and Environment, Swedish University of Agricultural Sciences, Box 7014, SE-750 07, Uppsala, Sweden
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3
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Yuan J, Peng M, Tang G, Wang Y. Fine root production, mortality, and turnover in response to simulated nitrogen deposition in the subtropical Abies georgei (Orr) forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171404. [PMID: 38432381 DOI: 10.1016/j.scitotenv.2024.171404] [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: 08/30/2023] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/05/2024]
Abstract
Increased nitrogen deposition has important effects on below-ground ecological processes. Fine roots are the most active part of the root system in terms of physiological activity and the main organs for nutrient and water uptake by plants. However, there is still a limited understanding of how nitrogen deposition affects the fine root dynamics in subtropical Abies georgei (Orr) forests. Consequently, a three-year field experiment was conducted to quantify the effects of three forms of nitrogen sources ((NH4)2SO4, NaNO3, and NH4NO3) at four levels (0, 5, 15, and 30 kg N·ha-1·yr-1) on the fine root dynamics in Abies georgei forests using a randomized block-group experimental design and minirhizotron technique. The first year of nitrogen addition did not affect the first-class fine roots (FR1, 0 < diameter < 0.5 mm) and second-class fine roots (FR2, 0.5 < diameter < 1.0 mm). The next two years of nitrogen addition significantly increased the production, mortality, and turnover of FR1 and FR2; the three year of nitrogen addition did not affect the dynamics of the third- class fine roots (FR3, 1.0 < diameter < 1.5 mm) and fourth- class fine roots (FR4,1.5 < diameter < 2.0 mm). Nitrogen addition positively affected the dynamics of FR1, FR2, FR3 and FR4 by positively affecting the carbon, nitrogen, and phosphorus contents of fine roots and indirectly affecting the soil pH. Increased carbon allocation to FR1 and FR2 may represent a phosphorus acquisition strategy when nitrogen is not the limiting factor. The nitrogen addition forms and levels affected the fine root dynamics in the following orde: NH4NO3 > (NH4)2SO4 > NaNO3 and high nitrogen > medium nitrogen > low nitrogen. The results suggest that the different-diameter fine root dynamics respond differently to different nitrogen addition forms and levels, and linking the different-diameter fine roots to nitrogen deposition is crucial.
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Affiliation(s)
- Jiyou Yuan
- School of Ecology and Environmental Sciences & Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming, Yunnan 650091, China.
| | - Mingchun Peng
- School of Ecology and Environmental Sciences & Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming, Yunnan 650091, China.
| | - Guoyong Tang
- Institute of Highland Forest Science, Chinese Academy of Forestry, Kunming 650233, China.
| | - Yun Wang
- Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, College of Resources and Environment, Linyi University, Linyi 276000, China.
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4
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Roy F, Ibayev O, Arnstadt T, Bässler C, Borken W, Groß C, Hoppe B, Hossen S, Kahl T, Moll J, Noll M, Purahong W, Schreiber J, Weisser WW, Hofrichter M, Kellner H. Nitrogen addition increases mass loss of gymnosperm but not of angiosperm deadwood without changing microbial communities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 900:165868. [PMID: 37516186 DOI: 10.1016/j.scitotenv.2023.165868] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 07/21/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Enhanced nitrogen (N) deposition due to combustion of fossil fuels and agricultural fertilization is a global phenomenon which has severely altered carbon (C) and N cycling in temperate forest ecosystems in the northern hemisphere. Although deadwood holds a substantial amount of C in forest ecosystems and thus plays a crucial role in nutrient cycling, the effect of increased N deposition on microbial processes and communities, wood chemical traits and deadwood mass loss remains unclear. Here, we simulated high N deposition rates by adding reactive N in form of ammonium-nitrate (40 kg N ha-1 yr-1) to deadwood of 13 temperate tree species over nine years in a field experiment in Germany. Non-treated deadwood from the same logs served as control with background N deposition. Our results show that chronically elevated N levels alters deadwood mass loss alongside respiration, enzymatic activities and wood chemistry depending on tree clade and species. In gymnosperm deadwood, elevated N increased mass loss by +38 %, respiration by +37 % and increased laccase activity 12-fold alongside increases of white-rot fungal abundance +89 % (p = 0.03). Furthermore, we observed marginally significant (p = 0.06) shifts of bacterial communities in gymnosperm deadwood. In angiosperm deadwood, we did not detect consistent effects on mass loss, physico-chemical properties, extracellular enzymatic activity or changes in microbial communities except for changes in abundance of 10 fungal OTUs in seven tree species and 28 bacterial OTUs in 10 tree species. We conclude that N deposition alters decomposition processes exclusively in N limited gymnosperm deadwood in the long term by enhancing fungal activity as expressed by increases in respiration rate and extracellular enzyme activity with minor shifts in decomposing microbial communities. By contrast, deadwood of angiosperm tree species had higher N concentrations and mass loss as well as community composition did not respond to N addition.
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Affiliation(s)
- Friederike Roy
- Department of Bio- and Environmental Sciences, International Institute Zittau, Technische Universität Dresden, Markt 23, D-02763 Zittau, Germany
| | - Orkhan Ibayev
- Department of Bio- and Environmental Sciences, International Institute Zittau, Technische Universität Dresden, Markt 23, D-02763 Zittau, Germany
| | - Tobias Arnstadt
- Department of Bio- and Environmental Sciences, International Institute Zittau, Technische Universität Dresden, Markt 23, D-02763 Zittau, Germany
| | - Claus Bässler
- Institute for Ecology, Evolution and Diversity, Department of Conservation Biology, Goethe-Universität Frankfurt, Max-von-Laue-Str. 13, D-60438 Frankfurt am Main, Germany; National Park Bavarian Forest, Freyunger Str. 2, D-94481 Grafenau, Germany
| | - Werner Borken
- Institute for Soil Ecology, University of Bayreuth, Dr.-Hans-Frisch-Straße 1-3, D-95448 Bayreuth, Germany
| | - Christina Groß
- Institute for Soil Ecology, University of Bayreuth, Dr.-Hans-Frisch-Straße 1-3, D-95448 Bayreuth, Germany
| | - Björn Hoppe
- Institute for National and International Plant Health, Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Messeweg 11/12, D-38104 Braunschweig, Germany
| | - Shakhawat Hossen
- Institute for Bioanalysis, University of Applied Sciences Coburg, Friedrich-Streib-Straße 2, D-96450 Coburg, Germany
| | - Tiemo Kahl
- UNESCO-Biosphärenreservat Thüringer Wald, Schmiedefeld a. Rstg, Brunnenstraße 1, D-98528 Suhl, Germany
| | - Julia Moll
- Department of Soil Ecology, Helmholtz Centre for Environmental Research - UFZ, Th.-Lieser- Str. 4, D-06120 Halle (Saale), Germany
| | - Matthias Noll
- Institute for Bioanalysis, University of Applied Sciences Coburg, Friedrich-Streib-Straße 2, D-96450 Coburg, Germany
| | - Witoon Purahong
- Department of Soil Ecology, Helmholtz Centre for Environmental Research - UFZ, Th.-Lieser- Str. 4, D-06120 Halle (Saale), Germany
| | - Jasper Schreiber
- Institute for Ecology, Evolution and Diversity, Department of Conservation Biology, Goethe-Universität Frankfurt, Max-von-Laue-Str. 13, D-60438 Frankfurt am Main, Germany
| | - Wolfgang W Weisser
- Terrestrial Ecology Research Group, Technical University of Munich, D-85354 Freising, Germany
| | - Martin Hofrichter
- Department of Bio- and Environmental Sciences, International Institute Zittau, Technische Universität Dresden, Markt 23, D-02763 Zittau, Germany
| | - Harald Kellner
- Department of Bio- and Environmental Sciences, International Institute Zittau, Technische Universität Dresden, Markt 23, D-02763 Zittau, Germany.
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5
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Wu Y, Zhou H, Sun W, Zhao Q, Liang M, Chen W, Guo Z, Jiang Y, Jiang Y, Liu G, Xue S. Temperature sensitivity of soil enzyme kinetics under N and P fertilization in an alpine grassland, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156042. [PMID: 35597335 DOI: 10.1016/j.scitotenv.2022.156042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 05/14/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
Soil nutrient cycling can be best studied by supplementing the soil with N and P fertilizers. Soil enzyme kinetic parameters (Vmax and Km) can be used to reflect the maximum reaction rates and affinities of soil enzymes. However, how N and P fertilizers affect the temperature sensitivity of soil enzyme kinetics is poorly understood. Therefore, our study investigated the response of soil enzyme kinetic temperature sensitivity relevant to C, N, and P cycles based on a 9-year fertilization (N and P) experiment performed in an alpine grassland on the Qinghai-Tibetan Plateau in China. Our results showed the following: N and P addition positively affected the Km of β-glucosidase (BG); P and NP interaction significantly increased the Km of phosphatase (AP), indicating that N and P addition significantly negatively affected the substrate affinity of soil enzymes. The temperature sensitivity of Michaelis-Menten kinetics was different for different enzymes. N and P fertilization decreased the temperature sensitivity of Km of BG but increased the temperature sensitivity of the Km of N-acetyl-glucosaminidase (NAG) and AP. In our study, P and NP fertilization increased the temperature sensitivity and activation energy of the Vmax of BG, indicating that P elements promoted the secretion of more extracellular enzymes by soil microbes to cope with temperature changes. The enzymes involved in the soil N and P cycle responded to the exogenous N and P through increases and decreases in the temperature sensitivity of the Km and Vmax, respectively. This study is crucial for investigating the impact of nutrient input on soil ecosystem functions under future climate warming conditions.
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Affiliation(s)
- Yang Wu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - HuaKun Zhou
- Qinghai Provincial Key Laboratory of Restoration Ecology in Cold Regions, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810000, PR China; State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810000, PR China
| | - Wei Sun
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - QiFan Zhao
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - Meng Liang
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - WenJing Chen
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - ZiQi Guo
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China
| | - YaoKun Jiang
- Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry Water Resources, Yangling 712100, PR China
| | - Yue Jiang
- College of Economics & Management, Northwest A&F University, Yangling 712100, PR China
| | - GuoBin Liu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry Water Resources, Yangling 712100, PR China
| | - Sha Xue
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, PR China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry Water Resources, Yangling 712100, PR China.
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6
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Xing A, Du E, Shen H, Xu L, Zhao M, Liu X, Fang J. High-level nitrogen additions accelerate soil respiration reduction over time in a boreal forest. Ecol Lett 2022; 25:1869-1878. [PMID: 35763602 DOI: 10.1111/ele.14065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 05/20/2022] [Accepted: 06/07/2022] [Indexed: 11/29/2022]
Abstract
Increased nitrogen (N) inputs are widely recognised to reduce soil respiration (Rs), but how N deposition affects the temporal dynamics of Rs remains unclear. Using a decade-long fertilisation experiment in a boreal larch forest (Larix gmelini) in northeast China, we found that the effects of N additions on Rs showed a temporal shift from a positive effect in the short-term (increased by 8% on average in the first year) to a negative effect over the longer term (decreased by 21% on average in the 11th year). The rates of decrease in Rs for the higher N levels were almost twice as high as those of the low N level. Our results suggest that the reduction in Rs in response to increased N input is accelerated by high-level N additions, and experimental high N applications are likely to overestimate the contribution of N deposition to soil carbon sequestration in a boreal forest.
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Affiliation(s)
- Aijun Xing
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Enzai Du
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China
| | - Haihua Shen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Longchao Xu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Mengying Zhao
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xiuyuan Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Jingyun Fang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
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7
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Jörgensen K, Granath G, Strengbom J, Lindahl BD. Links between boreal forest management, soil fungal communities and below‐ground carbon sequestration. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Karolina Jörgensen
- Department of Soil and Environment Swedish University of Agricultural Sciences Uppsala Sweden
| | - Gustaf Granath
- Department of Ecology and Genetics Uppsala University Uppsala Sweden
| | - Joachim Strengbom
- Department of Ecology Swedish University of Agricultural Sciences Uppsala Sweden
| | - Björn D. Lindahl
- Department of Soil and Environment Swedish University of Agricultural Sciences Uppsala Sweden
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8
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Argiroff WA, Zak DR, Pellitier PT, Upchurch RA, Belke JP. Decay by ectomycorrhizal fungi couples soil organic matter to nitrogen availability. Ecol Lett 2021; 25:391-404. [PMID: 34787356 DOI: 10.1111/ele.13923] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 10/21/2021] [Accepted: 10/30/2021] [Indexed: 01/04/2023]
Abstract
Interactions between soil nitrogen (N) availability, fungal community composition, and soil organic matter (SOM) regulate soil carbon (C) dynamics in many forest ecosystems, but context dependency in these relationships has precluded general predictive theory. We found that ectomycorrhizal (ECM) fungi with peroxidases decreased with increasing inorganic N availability across a natural inorganic N gradient in northern temperate forests, whereas ligninolytic fungal saprotrophs exhibited no response. Lignin-derived SOM and soil C were negatively correlated with ECM fungi with peroxidases and were positively correlated with inorganic N availability, suggesting decay of lignin-derived SOM by these ECM fungi reduced soil C storage. The correlations we observed link SOM decay in temperate forests to tradeoffs in tree N nutrition and ECM composition, and we propose SOM varies along a single continuum across temperate and boreal ecosystems depending upon how tree allocation to functionally distinct ECM taxa and environmental stress covary with soil N availability.
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Affiliation(s)
- William A Argiroff
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, USA
| | - Donald R Zak
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter T Pellitier
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, USA
| | - Rima A Upchurch
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, USA
| | - Julia P Belke
- Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA
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9
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Suz LM, Bidartondo MI, van der Linde S, Kuyper TW. Ectomycorrhizas and tipping points in forest ecosystems. THE NEW PHYTOLOGIST 2021; 231:1700-1707. [PMID: 34110018 DOI: 10.1111/nph.17547] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/02/2021] [Indexed: 06/12/2023]
Abstract
The resilience of forests is compromised by human-induced environmental influences pushing them towards tipping points and resulting in major shifts in ecosystem state that might be difficult to reverse, are difficult to predict and manage, and can have vast ecological, economic and social consequences. The literature on tipping points has grown rapidly, but almost exclusively based on aquatic and aboveground systems. So far little effort has been made to make links to soil systems, where change is not as drastically apparent, timescales may differ and recovery may be slower. Predicting belowground ecosystem state transitions and recovery, and their impacts on aboveground systems, remains a major scientific, practical and policy challenge. Recently observed major changes in aboveground tree condition across European forests are probably causally linked to ectomycorrhizal (EM) fungal changes belowground. Based on recent breakthroughs in data collection and analysis, we apply tipping point theory to forests, including their belowground component, focusing on EM fungi; link environmental thresholds for EM fungi with nutrient imbalances in forest trees; explore the role of phenotypic plasticity in EM fungal adaptation to, and recovery from, environmental change; and propose major positive feedback mechanisms to understand, address and predict forest ecosystem tipping points.
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Affiliation(s)
| | - Martin I Bidartondo
- Royal Botanic Gardens, Kew, TW9 3DS, UK
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Sietse van der Linde
- Netherlands Food and Consumer Product Safety Authority, National Reference Centre, Wageningen, 6706 EA, the Netherlands
| | - Thomas W Kuyper
- Soil Biology Group, Wageningen University & Research, Wageningen, 6700 AA, the Netherlands
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10
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Carrara JE, Walter CA, Freedman ZB, Hostetler AN, Hawkins JS, Fernandez IJ, Brzostek ER. Differences in microbial community response to nitrogen fertilization result in unique enzyme shifts between arbuscular and ectomycorrhizal-dominated soils. GLOBAL CHANGE BIOLOGY 2021; 27:2049-2060. [PMID: 33462956 DOI: 10.1111/gcb.15523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 12/27/2020] [Indexed: 06/12/2023]
Abstract
While the effect of nitrogen (N) deposition on belowground carbon (C) cycling varies, emerging evidence shows that forest soils dominated by trees that associate with ectomycorrhizal fungi (ECM) store more C than soils dominated by trees that associate with arbuscular mycorrhizae (AM) with increasing N deposition. We hypothesized that this is due to unique nutrient cycling responses to N between AM and ECM-dominated soils. ECM trees primarily obtain N through fungal mining of soil organic matter subsidized by root-C. As such, we expected the largest N-induced responses of C and N cycling to occur in ECM rhizospheres and be driven by fungi. Conversely, as AM trees rely on bacterial scavengers in bulk soils to cycle N, we predicted the largest AM responses to be driven by shifts in bacteria and occur in bulk soils. To test this hypothesis, we measured microbial community composition, metatranscriptome profiles, and extracellular enzyme activity in bulk, rhizosphere, and organic horizon (OH) soils in AM and ECM-dominated soils at Bear Brook Watershed in Maine, USA. After 27 years of N fertilization, fungal community composition shifted across ECM soils, but bacterial communities shifted across AM soils. These shifts were mirrored by enhanced C relative to N mining enzyme activities in both mycorrhizal types, but this occurred in different soil fractions. In ECM stands these shifts occurred in rhizosphere soils, but in AM stands they occurred in bulk soils. Additionally, ECM OH soils exhibited the opposite response with declines in C relative to N mining. As rhizosphere soils account for only a small portion of total soil volume relative to bulk soils, coupled with declines in C to N enzyme activity in ECM OH soils, we posit that this may partly explain why ECM soils store more C than AM soils as N inputs increase.
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Affiliation(s)
- Joseph E Carrara
- Department of Biology, West Virginia University, Morgantown, WV, USA
| | | | - Zachary B Freedman
- Department of Soil Science, University of Wisconsin-Madison, Madison, WI, USA
| | | | | | - Ivan J Fernandez
- School of Forest Resources and Climate Change Institute, University of Maine, Orono, ME, USA
| | - Edward R Brzostek
- Department of Biology, West Virginia University, Morgantown, WV, USA
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11
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Lang AK, Jevon FV, Vietorisz CR, Ayres MP, Hatala Matthes J. Fine roots and mycorrhizal fungi accelerate leaf litter decomposition in a northern hardwood forest regardless of dominant tree mycorrhizal associations. THE NEW PHYTOLOGIST 2021; 230:316-326. [PMID: 33341954 DOI: 10.1111/nph.17155] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 12/10/2020] [Indexed: 06/12/2023]
Abstract
●Fine roots and mycorrhizal fungi may either stimulate leaf litter decomposition by providing free-living decomposers with root-derived carbon, or may slow decomposition through nutrient competition between mycorrhizal and saprotrophic fungi. ●We reduced the presence of fine roots and their associated mycorrhizal fungi in a northern hardwood forest in New Hampshire, USA by soil trenching. Plots spanned a mycorrhizal gradient from 96% arbuscular mycorrhizal (AM) associations to 100% ectomycorrhizal (ECM)-associated tree basal area. We incubated four species of leaf litter within these plots in areas with reduced access to roots and mycorrhizal fungi and in adjacent areas with intact roots and mycorrhizal fungi. ●Over a period of 608 d, we found that litter decayed more rapidly in the presence of fine roots and mycorrhizal hyphae regardless of the dominant tree mycorrhizal association. Root and mycorrhizal exclusion reduced the activity of acid phosphatase on decomposing litter. ●Our results indicate that both AM- and ECM-associated fine roots stimulate litter decomposition in this system. These findings suggest that the effect of fine roots and mycorrhizal fungi on litter decay in a particular ecosystem likely depends on whether interactions between mycorrhizal roots and saprotrophic fungi are antagonistic or facilitative.
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Affiliation(s)
- Ashley K Lang
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Fiona V Jevon
- Yale School of the Environment, Yale University, New Haven, CT, 06511, USA
| | | | - Matthew P Ayres
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
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12
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Moore JAM, Anthony MA, Pec GJ, Trocha LK, Trzebny A, Geyer KM, van Diepen LTA, Frey SD. Fungal community structure and function shifts with atmospheric nitrogen deposition. GLOBAL CHANGE BIOLOGY 2021; 27:1349-1364. [PMID: 33159820 DOI: 10.1111/gcb.15444] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 10/09/2020] [Indexed: 05/04/2023]
Abstract
Fungal decomposition of soil organic matter depends on soil nitrogen (N) availability. This ecosystem process is being jeopardized by changes in N inputs that have resulted from a tripling of atmospheric N deposition in the last century. Soil fungi are impacted by atmospheric N deposition due to higher N availability, as soils are acidified, or as micronutrients become increasingly limiting. Fungal communities that persist with chronic N deposition may be enriched with traits that enable them to tolerate environmental stress, which may trade-off with traits enabling organic matter decomposition. We hypothesized that fungal communities would respond to N deposition by shifting community composition and functional gene abundances toward those that tolerate stress but are weak decomposers. We sampled soils at seven eastern US hardwood forests where ambient N deposition varied from 3.2 to 12.6 kg N ha-1 year-1 , five of which also have experimental plots where atmospheric N deposition was simulated through fertilizer application treatments (25-50 kg N ha-1 year-1 ). Fungal community and functional responses to fertilizer varied across the ambient N deposition gradient. Fungal biomass and richness increased with simulated N deposition at sites with low ambient deposition and decreased at sites with high ambient deposition. Fungal functional genes involved in hydrolysis of organic matter increased with ambient N deposition while genes involved in oxidation of organic matter decreased. One of four genes involved in generalized abiotic stress tolerance increased with ambient N deposition. In summary, we found that the divergent response to simulated N deposition depended on ambient N deposition levels. Fungal biomass, richness, and oxidative enzyme potential were reduced by N deposition where ambient N deposition was high suggesting fungal communities were pushed beyond an environmental stress threshold. Fungal community structure and function responses to N enrichment depended on ambient N deposition at a regional scale.
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Affiliation(s)
- Jessica A M Moore
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA
| | - Mark A Anthony
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA
| | - Gregory J Pec
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA
| | - Lidia K Trocha
- Department of Plant Ecology and Nature Protection, Adam Mickiewicz University, Poznań, Poland
| | - Artur Trzebny
- Laboratory of Molecular Biology Techniques, Adam Mickiewicz University, Poznań, Poland
| | - Kevin M Geyer
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA
| | - Linda T A van Diepen
- Department of Ecosystem Science and Management, University of Wyoming, Laramie, WY, USA
| | - Serita D Frey
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA
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13
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Billings SA, Lajtha K, Malhotra A, Berhe AA, de Graaff MA, Earl S, Fraterrigo J, Georgiou K, Grandy S, Hobbie SE, Moore JAM, Nadelhoffer K, Pierson D, Rasmussen C, Silver WL, Sulman BN, Weintraub S, Wieder W. Soil organic carbon is not just for soil scientists: measurement recommendations for diverse practitioners. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02290. [PMID: 33426701 DOI: 10.1002/eap.2290] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 08/05/2020] [Accepted: 10/05/2020] [Indexed: 06/12/2023]
Abstract
Soil organic carbon (SOC) regulates terrestrial ecosystem functioning, provides diverse energy sources for soil microorganisms, governs soil structure, and regulates the availability of organically bound nutrients. Investigators in increasingly diverse disciplines recognize how quantifying SOC attributes can provide insight about ecological states and processes. Today, multiple research networks collect and provide SOC data, and robust, new technologies are available for managing, sharing, and analyzing large data sets. We advocate that the scientific community capitalize on these developments to augment SOC data sets via standardized protocols. We describe why such efforts are important and the breadth of disciplines for which it will be helpful, and outline a tiered approach for standardized sampling of SOC and ancillary variables that ranges from simple to more complex. We target scientists ranging from those with little to no background in soil science to those with more soil-related expertise, and offer examples of the ways in which the resulting data can be organized, shared, and discoverable.
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Affiliation(s)
- S A Billings
- Department of Ecology and Evolutionary Biology and Kansas Biological Survey, University of Kansas, Lawrence, Kansas, 66047, USA
| | - K Lajtha
- Department of Crop and Soil Sciences, Oregon State University, Corvallis, Oregon, 97331, USA
| | - A Malhotra
- Department of Earth System Science, Stanford University, Stanford, California, 94305, USA
| | - A A Berhe
- Department of Life and Environmental Sciences, University of California, Merced, Merced, California, 95344, USA
| | - M-A de Graaff
- Department of Biological Sciences, Boise State University, Boise, Idaho, 83725, USA
| | - S Earl
- Global Institute of Sustainability, Arizona State University, Tempe, Arizona, 85281, USA
| | - J Fraterrigo
- Department of Natural Resources and Environmental Sciences, and Program in Ecology, Evolution and Conservation Biology, University of Illinois, Urbana, Illinois, 61820, USA
| | - K Georgiou
- Department of Earth System Science, Stanford University, Stanford, California, 94305, USA
| | - S Grandy
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire, 03824, USA
| | - S E Hobbie
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, Minnesota, 55455, USA
| | - J A M Moore
- Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37830, USA
| | - K Nadelhoffer
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - D Pierson
- Department of Crop and Soil Sciences, Oregon State University, Corvallis, Oregon, 97331, USA
| | - C Rasmussen
- Department of Environmental Science, University of Arizona, Tucson, Arizona, 85721, USA
| | - W L Silver
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California, 94720, USA
| | - B N Sulman
- Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37830, USA
| | - S Weintraub
- National Ecological Observatory Network, Batelle, Boulder, Colorado, 80309, USA
| | - W Wieder
- Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, Colorado, 80307, USA
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, Colorado, 80303, USA
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14
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Argiroff WA, Zak DR, Upchurch RA, Salley SO, Grandy AS. Anthropogenic N deposition alters soil organic matter biochemistry and microbial communities on decaying fine roots. GLOBAL CHANGE BIOLOGY 2019; 25:4369-4382. [PMID: 31314956 DOI: 10.1111/gcb.14770] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 07/06/2019] [Indexed: 06/10/2023]
Abstract
Fine root litter is a primary source of soil organic matter (SOM), which is a globally important pool of C that is responsive to climate change. We previously established that ~20 years of experimental nitrogen (N) deposition has slowed fine root decay and increased the storage of soil carbon (C; +18%) across a widespread northern hardwood forest ecosystem. However, the microbial mechanisms that have directly slowed fine root decay are unknown. Here, we show that experimental N deposition has decreased the relative abundance of Agaricales fungi (-31%) and increased that of partially ligninolytic Actinobacteria (+24%) on decaying fine roots. Moreover, experimental N deposition has increased the relative abundance of lignin-derived compounds residing in SOM (+53%), and this biochemical response is significantly related to shifts in both fungal and bacterial community composition. Specifically, the accumulation of lignin-derived compounds in SOM is negatively related to the relative abundance of ligninolytic Mycena and Kuehneromyces fungi, and positively related to Microbacteriaceae. Our findings suggest that by altering the composition of microbial communities on decaying fine roots such that their capacity for lignin degradation is reduced, experimental N deposition has slowed fine root litter decay, and increased the contribution of lignin-derived compounds from fine roots to SOM. The microbial responses we observed may explain widespread findings that anthropogenic N deposition increases soil C storage in terrestrial ecosystems. More broadly, our findings directly link composition to function in soil microbial communities, and implicate compositional shifts in mediating biogeochemical processes of global significance.
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Affiliation(s)
- William A Argiroff
- School for Environment and Sustainability, University of Michigan, Ann Arbor, MI, USA
| | - Donald R Zak
- School for Environment and Sustainability, University of Michigan, Ann Arbor, MI, USA
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Rima A Upchurch
- School for Environment and Sustainability, University of Michigan, Ann Arbor, MI, USA
| | - Sydney O Salley
- School for Environment and Sustainability, University of Michigan, Ann Arbor, MI, USA
| | - A Stuart Grandy
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA
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15
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Zak DR, Argiroff WA, Freedman ZB, Upchurch RA, Entwistle EM, Romanowicz KJ. Anthropogenic N deposition, fungal gene expression, and an increasing soil carbon sink in the Northern Hemisphere. Ecology 2019; 100:e02804. [PMID: 31257580 DOI: 10.1002/ecy.2804] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/23/2019] [Accepted: 06/13/2019] [Indexed: 11/07/2022]
Abstract
Terrestrial ecosystems in the Northern Hemisphere are a globally important sink for anthropogenic CO2 in the Earth's atmosphere, slowing its accumulation as well as the pace of climate warming. With the use of a long-term field experiment (ca. 20 yr), we show that the expression of fungal class II peroxidase genes, which encode enzymes mediating the rate-limiting step of organic matter decay, are significantly downregulated (-60 to -80%) because of increases in anthropogenic N deposition; this response was consistent with a decline in extracellular peroxidase enzyme activity in soil, the slowing of organic-matter decay, and greater soil C storage. The reduction in peroxidase expression we document here occurred in the absence of a compositional shift in metabolically active fungi, indicating that an overall reduction in peroxidase expression underlies the slowing of decay and increases in soil C storage. This molecular mechanism has global implications for soil C storage and should be represented in coupled climate-biogeochemical models simulating the influence of enhanced terrestrial C storage on atmospheric CO2 and the future climate of an N-enriched Earth.
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Affiliation(s)
- Donald R Zak
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, 48109, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - William A Argiroff
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Zachary B Freedman
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, 48109, USA.,Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia, 26506, USA
| | - Rima A Upchurch
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Elizabeth M Entwistle
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, 48109, USA.,Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35233, USA
| | - Karl J Romanowicz
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, 48109, USA
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16
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Long-Term Nitrogen Addition Does Not Increase Soil Carbon Storage or Cycling Across Eight Temperate Forest and Grassland Sites on a Sandy Outwash Plain. Ecosystems 2019. [DOI: 10.1007/s10021-019-00357-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Kyaschenko J, Ovaskainen O, Ekblad A, Hagenbo A, Karltun E, Clemmensen KE, Lindahl BD. Soil fertility in boreal forest relates to root-driven nitrogen retention and carbon sequestration in the mor layer. THE NEW PHYTOLOGIST 2019; 221:1492-1502. [PMID: 30281792 DOI: 10.1111/nph.15454] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 08/17/2018] [Indexed: 06/08/2023]
Abstract
Boreal forest soils retain significant amounts of carbon (C) and nitrogen (N) in purely organic layers, but the regulation of organic matter turnover and the relative importance of leaf litter and root-derived inputs are not well understood. We combined bomb 14 C dating of organic matter with stable isotope profiling for Bayesian parameterization of an organic matter sequestration model. C and N dynamics were assessed across annual depth layers (cohorts), together representing 256 yr of organic matter accumulation. Results were related to ecosystem fertility (soil inorganic N, pH and litter C : N). Root-derived C was estimated to decompose two to 10 times more slowly than leaf litter, but more rapidly in fertile plots. The amounts of C and N per cohort declined during the initial 20 yr of decomposition, but, in older material, the amount of N per cohort increased, indicating N retention driven by root-derived C. The dynamics of root-derived inputs were more important than leaf litter dynamics in regulating the variation in organic matter accumulation along a forest fertility gradient. N retention in the rooting zone combined with impeded mining for N in less fertile ecosystems provides evidence for a positive feedback between ecosystem fertility and organic matter turnover.
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Affiliation(s)
- Julia Kyaschenko
- Department of Soil and Environment, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden
| | - Otso Ovaskainen
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, PO Box 65, FI-00014, Finland
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, N-7491, Trondheim, Norway
| | - Alf Ekblad
- School of Science and Technology, Örebro University, SE-701 82, Örebro, Sweden
| | - Andreas Hagenbo
- Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden
| | - Erik Karltun
- Department of Soil and Environment, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden
| | - Karina E Clemmensen
- Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden
| | - Björn D Lindahl
- Department of Soil and Environment, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden
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18
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Marinos RE, Bernhardt ES. Soil carbon losses due to higher pH offset vegetation gains due to calcium enrichment in an acid mitigation experiment. Ecology 2018; 99:2363-2373. [DOI: 10.1002/ecy.2478] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 06/15/2018] [Accepted: 07/13/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Richard E. Marinos
- Nicholas School of the Environment Duke University Durham North Carolina 27708 USA
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19
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Anthropogenic N Deposition Alters the Composition of Expressed Class II Fungal Peroxidases. Appl Environ Microbiol 2018; 84:AEM.02816-17. [PMID: 29453258 DOI: 10.1128/aem.02816-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/09/2018] [Indexed: 01/13/2023] Open
Abstract
Here, we present evidence that ca. 20 years of experimental N deposition altered the composition of lignin-decaying class II peroxidases expressed by forest floor fungi, a response which has occurred concurrently with reductions in plant litter decomposition and a rapid accumulation of soil organic matter. This finding suggests that anthropogenic N deposition has induced changes in the biological mediation of lignin decay, the rate limiting step in plant litter decomposition. Thus, an altered composition of transcripts for a critical gene that is associated with terrestrial C cycling may explain the increased soil C storage under long-term increases in anthropogenic N deposition.IMPORTANCE Fungal class II peroxidases are enzymes that mediate the rate-limiting step in the decomposition of plant material, which involves the oxidation of lignin and other polyphenols. In field experiments, anthropogenic N deposition has increased soil C storage in forests, a result which could potentially arise from anthropogenic N-induced changes in the composition of class II peroxidases expressed by the fungal community. In this study, we have gained unique insight into how anthropogenic N deposition, a widespread agent of global change, affects the expression of a functional gene encoding an enzyme that plays a critical role in a biologically mediated ecosystem process.
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