1
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Wang Z, Li D, Sun X, Chen H, Xiao K, Wang K. Effects of Lithology on Asymbiotic N2 Fixation in Subtropical Secondary Forests, Southwest China. Ecosystems 2023. [DOI: 10.1007/s10021-023-00824-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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2
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Cleveland CC, Reis CRG, Perakis SS, Dynarski KA, Batterman SA, Crews TE, Gei M, Gundale MJ, Menge DNL, Peoples MB, Reed SC, Salmon VG, Soper FM, Taylor BN, Turner MG, Wurzburger N. Exploring the Role of Cryptic Nitrogen Fixers in Terrestrial Ecosystems: A Frontier in Nitrogen Cycling Research. Ecosystems 2022. [DOI: 10.1007/s10021-022-00804-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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3
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Chen Y, Wang Q, Zhu J, Xi Y, Zhang Q, Dai G, He N, Yu G. Atmospheric Wet Iron, Molybdenum, and Vanadium Deposition in Chinese Terrestrial Ecosystems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12898-12905. [PMID: 36026692 DOI: 10.1021/acs.est.2c03213] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Iron (Fe), molybdenum (Mo), and vanadium (V) are the main components of the three known biological nitrogenases, which constrain nitrogen fixation and affect ecosystem productivity. Atmospheric deposition is an important pathway of these trace metals into ecosystems. Here, we explored the deposition flux, spatiotemporal pattern, and influencing factors of atmospheric wet Fe, Mo, and V deposition based on China Wet Deposition Observation Network (ChinaWD) data from 2016 to 2020. Our results showed that atmospheric wet Fe, Mo, and V deposition was 7.77 ± 7.24, 0.16 ± 0.11, and 0.13 ± 0.12 mg m-2 a-1 in Chinese terrestrial ecosystems, respectively, and revealed obvious spatial patterns but no significant annual trends. Wet Fe deposition was significantly correlated with the soil Fe content. Mo and V deposition was more affected by anthropogenic activities than Fe deposition. Wet Mo deposition was significantly affected by Mo ore reserves and waste incineration. V deposition was significantly correlated with domestic biomass burning. This study quantified wet Fe, Mo, and V deposition in China for the first time, and the implications of atmospheric trace metal deposition on biological nitrogen fixation were discussed.
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Affiliation(s)
- Yanran Chen
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Qiufeng Wang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Jianxing Zhu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
| | - Yue Xi
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Qiongyu Zhang
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Guanhua Dai
- Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, Antu 133613, China
| | - Nianpeng He
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Guirui Yu
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
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4
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Sun X, Li D, Chen H, Ma Z, Xiao K, Yan J, Wang Z, Duan P. Divergent responses of symbiotic and asymbiotic N
2
fixation to seawater additions. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xibin Sun
- Key Laboratory of Agro‐ecological Processes in Subtropical Region Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha China
- State Key Laboratory of Biocontrol School of Ecology Sun Yat‐sen University Guangzhou China
| | - Dejun Li
- Key Laboratory of Agro‐ecological Processes in Subtropical Region Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha China
- Huanjiang Observation and Research Station for Karst Ecosystems Chinese Academy of Sciences Huanjiang China
| | - Hao Chen
- State Key Laboratory of Biocontrol School of Ecology Sun Yat‐sen University Guangzhou China
| | - Zilong Ma
- State Key Laboratory of Biocontrol School of Ecology Sun Yat‐sen University Guangzhou China
| | - Kongcao Xiao
- Key Laboratory of Agro‐ecological Processes in Subtropical Region Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha China
- Huanjiang Observation and Research Station for Karst Ecosystems Chinese Academy of Sciences Huanjiang China
| | - Junhua Yan
- South China Botanical Garden Chinese Academy of Sciences Guangzhou China
| | - Zhenchuan Wang
- Key Laboratory of Environment Change and Resources Use in Beibu Gulf Ministry of Education Nanning Normal University Nanning China
| | - Pengpeng Duan
- Key Laboratory of Agro‐ecological Processes in Subtropical Region Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha China
- Huanjiang Observation and Research Station for Karst Ecosystems Chinese Academy of Sciences Huanjiang China
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5
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Aloo BN, Mbega ER, Makumba BA, Tumuhairwe JB. Effects of agrochemicals on the beneficial plant rhizobacteria in agricultural systems. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:60406-60424. [PMID: 34535866 DOI: 10.1007/s11356-021-16191-5] [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] [Received: 04/06/2021] [Accepted: 08/23/2021] [Indexed: 06/13/2023]
Abstract
Conventional agriculture relies heavily on chemical pesticides and fertilizers to control plant pests and diseases and improve production. Nevertheless, the intensive and prolonged use of agrochemicals may have undesirable consequences on the structure, diversity, and activities of soil microbiomes, including the beneficial plant rhizobacteria in agricultural systems. Although literature continues to mount regarding the effects of these chemicals on the beneficial plant rhizobacteria in agricultural systems, our understanding of them is still limited, and a proper account is required. With the renewed efforts and focus on agricultural and environmental sustainability, understanding the effects of different agrochemicals on the beneficial plant rhizobacteria in agricultural systems is both urgent and important to deduce practical solutions towards agricultural sustainability. This review critically evaluates the effects of various agrochemicals on the structure, diversity, and functions of the beneficial plant rhizobacteria in agricultural systems and propounds on the prospects and general solutions that can be considered to realize sustainable agricultural systems. This can be useful in understanding the anthropogenic effects of common and constantly applied agrochemicals on symbiotic systems in agricultural soils and shed light on the need for more environmentally friendly and sustainable agricultural practices.
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Affiliation(s)
- Becky Nancy Aloo
- Department of Biological Sciences, University of Eldoret, P.O. Box 1125-30100, Eldoret, Kenya.
| | - Ernest Rashid Mbega
- Department of Sustainable Agriculture and Biodiversity Conservation, Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania
| | - Billy Amendi Makumba
- Department of Biological Sciences, Moi University, P.O. Box 3900-30100, Eldoret, Kenya
| | - John Baptist Tumuhairwe
- Department of Agricultural Production, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box, 7062, Kampala, Uganda
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6
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Reis CRG, Pacheco FS, Reed SC, Tejada G, Nardoto GB, Forti MC, Ometto JP. Biological nitrogen fixation across major biomes in Latin America: Patterns and global change effects. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 746:140998. [PMID: 32763600 DOI: 10.1016/j.scitotenv.2020.140998] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 07/11/2020] [Accepted: 07/13/2020] [Indexed: 06/11/2023]
Abstract
Biological nitrogen fixation (BNF) supports terrestrial primary productivity and plays key roles in mediating human-induced changes in global nitrogen (N) and carbon cycling. However, there are still critical uncertainties in our understanding of the amount of BNF occurring across terrestrial ecosystems, and of how terrestrial BNF will respond to global change. We synthesized BNF data from Latin America, a region reported to sustain some of the highest BNF rates on Earth, but that is underrepresented in previous data syntheses. We used meta-analysis and modeling approaches to estimate BNF rates across Latin America's major biomes and to evaluate the potential effects of increased N deposition and land-use change on these rates. Unmanaged tropical and subtropical moist forests sustained observed and predicted total BNF rates of 10 ± 1 and 14 ± 1 kg N ha-1 y-1, respectively, supporting the hypothesis that these forests sustain lower BNF rates than previously thought. Free-living BNF accounted for two-thirds of the total BNF in these forests. Despite an average 30% reduction of free-living BNF in response to experimental N-addition, our results suggest free-living BNF rate responses to current and projected N deposition across tropical and subtropical moist forests are small. In contrast, the conversion of unmanaged ecosystems to crop and pasture lands increased BNF rates across all terrestrial biomes, mostly in savannas, grasslands, and dry forests, increasing BNF rates 2-fold. The information obtained here provides a more comprehensive understanding of BNF patterns for Latin America.
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Affiliation(s)
- Carla R G Reis
- Center for Earth System Science, National Institute for Space Research (INPE), Av. dos Astronautas 1758, São José dos Campos, São Paulo 12227-010, Brazil.
| | - Felipe S Pacheco
- Center for Earth System Science, National Institute for Space Research (INPE), Av. dos Astronautas 1758, São José dos Campos, São Paulo 12227-010, Brazil
| | - Sasha C Reed
- U.S. Geological Survey, Southwest Biological Science Center, 2290, S.W. Resource Blvd, Moab, UT 84532, USA
| | - Graciela Tejada
- Center for Earth System Science, National Institute for Space Research (INPE), Av. dos Astronautas 1758, São José dos Campos, São Paulo 12227-010, Brazil
| | - Gabriela B Nardoto
- Department of Ecology, Campus Darcy Ribeiro, University of Brasilia, Brasilia, Federal District 70910-900, Brazil
| | - Maria C Forti
- Center for Earth System Science, National Institute for Space Research (INPE), Av. dos Astronautas 1758, São José dos Campos, São Paulo 12227-010, Brazil
| | - Jean P Ometto
- Center for Earth System Science, National Institute for Space Research (INPE), Av. dos Astronautas 1758, São José dos Campos, São Paulo 12227-010, Brazil
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7
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Wong MY, Neill C, Marino R, Silvério D, Howarth RW. Molybdenum, phosphorus, and pH do not constrain nitrogen fixation in a tropical forest in the southeastern Amazon. Ecology 2020; 102:e03211. [PMID: 32981087 DOI: 10.1002/ecy.3211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 07/06/2020] [Accepted: 08/06/2020] [Indexed: 01/09/2023]
Abstract
High rates of biological nitrogen fixation (BNF) are commonly reported for tropical forests, but most studies have been conducted in regions that receive substantial inputs of molybdenum (Mo) from atmospheric dust and sea-salt aerosols. Even in these regions, the low availability of Mo can constrain free-living BNF catalyzed by heterotrophic bacteria and archaea. We hypothesized that in regions where atmospheric inputs of Mo are low and soils are highly weathered, such as the southeastern Amazon, Mo would constrain BNF. We also hypothesized that the high soil acidity, characteristic of the Amazon Basin, would further constrain Mo availability and therefore soil BNF. We conducted two field experiments across the wet and dry seasons, adding Mo, phosphorus (P), and lime alone and in combination to the forest floor in the southeastern Amazon. We sampled soils and litter immediately, and then weeks and months after the applications, and measured Mo and P availability through resin extractions and BNF with the acetylene reduction assay. The experimental additions of Mo and P increased their availability and the lime increased soil pH. While the combination of Mo and P increased BNF at some time points, BNF rates did not increase strongly or consistently across the study as a whole, suggesting that Mo, P, and soil pH are not the dominant controls over BNF. In a separate short-term laboratory experiment, BNF did not respond strongly to Mo and P even when labile carbon was added. We postulate that high nitrogen (N) availability in this area of the Amazon, as indicated by the stoichiometry of soils and vegetation and the high nitrate soil stocks, likely suppresses BNF at this site. These patterns may also extend across highly weathered soils with high N availability in other topographically stable regions of the tropics.
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Affiliation(s)
- Michelle Y Wong
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, 14853, USA
| | | | - Roxanne Marino
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, 14853, USA
| | - Divino Silvério
- Instituto de Pesquisa Ambiental da Amazônia (IPAM), Canarana, Mato Grosso, 78640-000, Brazil.,Departamento de Biologia, Universidade Federal Rural da Amazônia-UFRA, Capitão Poço, Pará, 68650-000, Brazil
| | - Robert W Howarth
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, 14853, USA.,Woods Hole Research Center, Falmouth, Massachusetts, 02450, USA
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8
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Zhang X, Ward BB, Sigman DM. Global Nitrogen Cycle: Critical Enzymes, Organisms, and Processes for Nitrogen Budgets and Dynamics. Chem Rev 2020; 120:5308-5351. [DOI: 10.1021/acs.chemrev.9b00613] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xinning Zhang
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
- Princeton Environmental Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Bess B. Ward
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
- Princeton Environmental Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Daniel M. Sigman
- Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
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9
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Akther H, Rousk K. High heavy metal load does not inhibit nitrogen fixation in moss-cyanobacteria associations. ECOTOXICOLOGY (LONDON, ENGLAND) 2019; 28:1169-1176. [PMID: 31696444 DOI: 10.1007/s10646-019-02127-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/12/2019] [Indexed: 06/10/2023]
Abstract
Nitrogen (N2) fixation by moss-associated cyanobacteria is one of the main sources of new N input in pristine ecosystems such as boreal forests and arctic tundra. Given the non-vascular physiology of mosses, they are especially sensitive to e.g. increased N input and heavy metal deposition. While the effects of increased N input on moss-associated N2 fixation has been comprehensively assessed, hardly any reports exist on the effects of increased heavy metal load on this key ecosystem function. To address this knowledge gap, we made use of an extreme metal pollution gradient in boreal forests of Northern Sweden originating from a metal mine and its associated smelters. We collected the common moss Pleurozium schreberi, known to host cyanobacteria, along a distance gradient away from the metal source of pollution and measured moss-metal content (Fe, Cu, Zn, Pb) as well as N2 fixation. We found a strong distance gradient in moss-metal content for all investigated metals: a sharp decline in metal content with distance away from the metal pollution source. However, we found a similarly steep gradient in moss-associated N2 fixation, with highest activity closest to the metal source of pollution. Hence, while mosses may be sensitive to increased heavy metal inputs, the activity of colonising cyanobacteria seem to be unaffected by heavy metals, and consequently, ecosystem function may not be compromised by elevated metal input.
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Affiliation(s)
- Hasna Akther
- Department of Biology, Terrestrial Ecology Section, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark
| | - Kathrin Rousk
- Department of Biology, Terrestrial Ecology Section, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark.
- Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark.
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10
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Biological Nitrogen Fixation Does Not Replace Nitrogen Losses After Forest Fires in the Southeastern Amazon. Ecosystems 2019. [DOI: 10.1007/s10021-019-00453-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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11
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Zheng M, Zhou Z, Luo Y, Zhao P, Mo J. Global pattern and controls of biological nitrogen fixation under nutrient enrichment: A meta-analysis. GLOBAL CHANGE BIOLOGY 2019; 25:3018-3030. [PMID: 31120621 DOI: 10.1111/gcb.14705] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 05/05/2019] [Accepted: 05/15/2019] [Indexed: 06/09/2023]
Abstract
Biological nitrogen (N) fixation (BNF), an important source of N in terrestrial ecosystems, plays a critical role in terrestrial nutrient cycling and net primary productivity. Currently, large uncertainty exists regarding how nutrient availability regulates terrestrial BNF and the drivers responsible for this process. We conducted a global meta-analysis of terrestrial BNF in response to N, phosphorus (P), and micronutrient (Micro) addition across different biomes (i.e, tropical/subtropical forest, savanna, temperate forest, grassland, boreal forest, and tundra) and explored whether the BNF responses were affected by fertilization regimes (nutrient-addition rates, duration, and total load) and environmental factors (mean annual temperature [MAT], mean annual precipitation [MAP], and N deposition). The results showed that N addition inhibited terrestrial BNF (by 19.0% (95% confidence interval [CI]: 17.7%-20.3%); hereafter), Micro addition stimulated terrestrial BNF (30.4% [25.7%-35.3%]), and P addition had an inconsistent effect on terrestrial BNF, i.e., inhibiting free-living N fixation (7.5% [4.4%-10.6%]) and stimulating symbiotic N fixation (85.5% [25.8%-158.7%]). Furthermore, the response ratios (i.e., effect sizes) of BNF to nutrient addition were smaller in low-latitude (<30°) biomes (8.5%-36.9%) than in mid-/high-latitude (≥30°) biomes (32.9%-61.3%), and the sensitivity (defined as the absolute value of response ratios) of BNF to nutrients in mid-/high-latitude biomes decreased with decreasing latitude (p ≤ 0.009; linear/logarithmic regression models). Fertilization regimes did not affect this phenomenon (p > 0.05), but environmental factors did affect it (p < 0.001) because MAT, MAP, and N deposition accounted for 5%-14%, 10%-32%, and 7%-18% of the variance in the BNF response ratios in cold (MAT < 15°C), low-rainfall (MAP < 2,500 mm), and low-N-deposition (<7 kg ha-1 year-1 ) biomes, respectively. Overall, our meta-analysis depicts a global pattern of nutrient impacts on terrestrial BNF and indicates that certain types of global change (i.e., warming, elevated precipitation and N deposition) may reduce the sensitivity of BNF in response to nutrient enrichment in mid-/high-latitude biomes.
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Affiliation(s)
- Mianhai Zheng
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhenghu Zhou
- Center for Ecological Research, Northeast Forestry University, Harbin, China
| | - Yiqi Luo
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ
| | - Ping Zhao
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Jiangming Mo
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
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12
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Goth A, Michelsen A, Rousk K. Railroad derived nitrogen and heavy metal pollution does not affect nitrogen fixation associated with mosses and lichens at a tundra site in Northern Sweden. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 247:857-865. [PMID: 30731311 DOI: 10.1016/j.envpol.2019.01.101] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/07/2019] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
Traffic derived nitrogen (N) and heavy metal pollution is a well-known phenomenon, but little explored in otherwise pristine ecosystems such as subarctic tundra. Here, the main source of N input to the ecosystem is via N2 fixation by moss- and lichen-associated bacteria. While inhibitory effects of N deposition on moss-associated N2 fixation have been reported, we still lack understanding of the effects of traffic derived N and heavy metal deposition on this ecosystem function in an otherwise pristine setting. To test this, we established a distance gradient (0-1280 m) away from a metal pollution source -a railway transporting iron ore that passes through a subarctic birch forest. We assessed the effects of railway-derived pollution on N2 fixation associated with two moss species Pleurozium schreberi, Hylocomium splendens and with the lichen Peltigera aphthosa. Deposition and availability of N and heavy metals (Fe, Cu, Zn, Pb) as well as the respective contents in moss, lichen and soil was assessed. While we found a steep gradient in metal concentration in moss, lichen and soil with distance away from the pollution source, N deposition did not change, and with that, we could not detect a distance gradient in moss- or lichen-associated N2 fixation. Hence, our results indicate that N2 fixing bacteria are either not inhibited by heavy metal deposition, or that they are protected within the moss carpet and lichen tissue.
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Affiliation(s)
- Astrid Goth
- Department of Biology, Terrestrial Ecology Section, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark
| | - Anders Michelsen
- Department of Biology, Terrestrial Ecology Section, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark; Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark
| | - Kathrin Rousk
- Department of Biology, Terrestrial Ecology Section, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark; Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark.
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13
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Winbourne JB, Houlton BZ. Plant-soil feedbacks on free-living nitrogen fixation over geological time. Ecology 2018; 99:2496-2505. [PMID: 30076606 DOI: 10.1002/ecy.2486] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 07/04/2018] [Accepted: 07/23/2018] [Indexed: 11/09/2022]
Abstract
Free-living heterotrophic nitrogen fixation (FNF) is a widespread nitrogen input pathway in terrestrial ecosystems. However, questions remain over the relative influence of co-occurring controls on patterns of heterotrophic FNF activity, especially across generalized stages of primary succession, from biomass accumulation to retrogressive phases. Here, we experimentally test two alternative hypotheses regarding FNF rates during ecosystem development: (H1) site (i.e., changes in soil fertility during succession) is the primary driver of leaf-litter FNF rates, vs. (H2) leaf-litter chemistry is the primary determinant of FNF activity across a broad range of ecosystem conditions. We evaluated these hypotheses across a well-studied soil chronosequence in California (i.e., the Ecological Staircase), which spans ~1 million years of ecosystem development and displays extreme ranges in plant-soil nutrient conditions, culminating in the nutrient depleted and stunted Pygmy forest. Across this successional gradient, we implemented a reciprocal leaf-litter transplant and a common garden litter bag decomposition experiment with senesced needles of Pinus muricata. Our results support H1: rates of FNF were similar for all leaf-litter types decomposed at the same site regardless of initial leaf-litter C and nutrient contents. FNF rates sharply declined from the maximal to retrogressive stage of succession. Trends in P dynamics during decomposition suggest an important role of P in regulating FNF. For example, P. muricata litter collected from the infertile Pygmy site displayed substantially higher FNF rates when decomposed at the fertile site, in part by immobilizing significant quantities of P from the soil at the fertile site. Conversely, P. muricata litter collected from the fertile site decomposed more slowly at the Pygmy site, with concomitant declines in FNF rates that matched those of Pygmy site litter decomposed in situ. These results are consistent with the idea that, over millennia, long-term declines in P availability feedback to constrain FNF rates, in part explaining the emergence of extremely nutrient-poor and retrograded ecosystems.
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Affiliation(s)
- Joy B Winbourne
- Department of Land, Air, and Water Resources, University of California, Davis, California, 95616, USA.,Department of Earth and Environment, Boston University, Boston, Massachusetts, 02215, USA
| | - Benjamin Z Houlton
- Department of Land, Air, and Water Resources, University of California, Davis, California, 95616, USA
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14
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Zheng M, Zhang W, Luo Y, Li D, Wang S, Huang J, Lu X, Mo J. Stoichiometry controls asymbiotic nitrogen fixation and its response to nitrogen inputs in a nitrogen-saturated forest. Ecology 2018; 99:2037-2046. [DOI: 10.1002/ecy.2416] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 05/02/2018] [Accepted: 05/14/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Mianhai Zheng
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems; Guangdong Provincial Key Laboratory of Applied Botany; South China Botanical Garden; Chinese Academy of Sciences; Guangzhou 510650 China
- Department of Biological Sciences; Northern Arizona University; Flagstaff Arizona 86011 USA
- University of Chinese Academy of Sciences; Beijing 100039 China
| | - Wei Zhang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems; Guangdong Provincial Key Laboratory of Applied Botany; South China Botanical Garden; Chinese Academy of Sciences; Guangzhou 510650 China
| | - Yiqi Luo
- Department of Biological Sciences; Northern Arizona University; Flagstaff Arizona 86011 USA
- Department of Microbiology and Plant Biology; University of Oklahoma; Norman Oklahoma 73019 USA
| | - Dejun Li
- Key Laboratory of Agro-ecological Processes in Subtropical Region; Institute of Subtropical Agriculture; Chinese Academy of Sciences; Changsha 410125 China
| | - Senhao Wang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems; Guangdong Provincial Key Laboratory of Applied Botany; South China Botanical Garden; Chinese Academy of Sciences; Guangzhou 510650 China
- University of Chinese Academy of Sciences; Beijing 100039 China
| | - Juan Huang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems; Guangdong Provincial Key Laboratory of Applied Botany; South China Botanical Garden; Chinese Academy of Sciences; Guangzhou 510650 China
| | - Xiankai Lu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems; Guangdong Provincial Key Laboratory of Applied Botany; South China Botanical Garden; Chinese Academy of Sciences; Guangzhou 510650 China
| | - Jiangming Mo
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems; Guangdong Provincial Key Laboratory of Applied Botany; South China Botanical Garden; Chinese Academy of Sciences; Guangzhou 510650 China
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15
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Legume abundance along successional and rainfall gradients in Neotropical forests. Nat Ecol Evol 2018; 2:1104-1111. [PMID: 29807995 DOI: 10.1038/s41559-018-0559-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 04/18/2018] [Indexed: 11/08/2022]
Abstract
The nutrient demands of regrowing tropical forests are partly satisfied by nitrogen-fixing legume trees, but our understanding of the abundance of those species is biased towards wet tropical regions. Here we show how the abundance of Leguminosae is affected by both recovery from disturbance and large-scale rainfall gradients through a synthesis of forest inventory plots from a network of 42 Neotropical forest chronosequences. During the first three decades of natural forest regeneration, legume basal area is twice as high in dry compared with wet secondary forests. The tremendous ecological success of legumes in recently disturbed, water-limited forests is likely to be related to both their reduced leaflet size and ability to fix N2, which together enhance legume drought tolerance and water-use efficiency. Earth system models should incorporate these large-scale successional and climatic patterns of legume dominance to provide more accurate estimates of the maximum potential for natural nitrogen fixation across tropical forests.
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Averill C, Waring B. Nitrogen limitation of decomposition and decay: How can it occur? GLOBAL CHANGE BIOLOGY 2018; 24:1417-1427. [PMID: 29121419 DOI: 10.1111/gcb.13980] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 11/02/2017] [Indexed: 05/07/2023]
Abstract
The availability of nitrogen (N) is a critical control on the cycling and storage of soil carbon (C). Yet, there are conflicting conceptual models to explain how N availability influences the decomposition of organic matter by soil microbial communities. Several lines of evidence suggest that N availability limits decomposition; the earliest stages of leaf litter decay are associated with a net import of N from the soil environment, and both observations and models show that high N organic matter decomposes more rapidly. In direct contrast to these findings, experimental additions of inorganic N to soils broadly show a suppression of microbial activity, which is inconsistent with N limitation of decomposition. Resolving this apparent contradiction is critical to representing nutrient dynamics in predictive ecosystem models under a multitude of global change factors that alter soil N availability. Here, we propose a new conceptual framework, the Carbon, Acidity, and Mineral Protection hypothesis, to understand the effects of N availability on soil C cycling and storage and explore the predictions of this framework with a mathematical model. Our model simulations demonstrate that N addition can have opposing effects on separate soil C pools (particulate and mineral-protected carbon) because they are differentially affected by microbial biomass growth. Moreover, changes in N availability are frequently linked to shifts in soil pH or osmotic stress, which can independently affect microbial biomass dynamics and mask N stimulation of microbial activity. Thus, the net effect of N addition on soil C is dependent upon interactions among microbial physiology, soil mineralogy, and soil acidity. We believe that our synthesis provides a broadly applicable conceptual framework to understand and predict the effect of changes in soil N availability on ecosystem C cycling under global change.
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Affiliation(s)
- Colin Averill
- NOAA Climate and Global Change Postdoctoral Fellow, Boston University, Boston, MA, USA
| | - Bonnie Waring
- Biology Department and Ecology Center, Utah State University, Logan, UT, USA
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17
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Dynarski KA, Houlton BZ. Nutrient limitation of terrestrial free-living nitrogen fixation. THE NEW PHYTOLOGIST 2018; 217:1050-1061. [PMID: 29165820 DOI: 10.1111/nph.14905] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/18/2017] [Indexed: 05/27/2023]
Abstract
Nitrogen (N) fixation by free-living bacteria is a primary N input pathway in many ecosystems and sustains global plant productivity. Uncertainty exists over the importance of N, phosphorus (P) and molybdenum (Mo) availability in controlling free-living N fixation rates. Here, we investigate the geographic occurrence and variability of nutrient constraints to free-living N fixation in the terrestrial biosphere. We compiled data from studies measuring free-living N fixation in response to N, P and Mo fertilizers. We used meta-analysis to quantitatively determine the extent to which N, P and Mo stimulate or suppress N fixation, and if environmental variables influence the degree of nutrient limitation of N fixation. Across our compiled dataset, free-living N fixation is suppressed by N fertilization and stimulated by Mo fertilization. Additionally, free-living N fixation is stimulated by P additions in tropical forests. These findings suggest that nutrient limitation is an intrinsic property of the biochemical demands of N fixation, constraining free-living N fixation in the terrestrial biosphere. These findings have implications for understanding the causes and consequences of N limitation in coupled nutrient cycles, as well as modeling and forecasting nutrient controls over carbon-climate feedbacks.
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Affiliation(s)
- Katherine A Dynarski
- Department of Land, Air, and Water Resources, University of California, Davis, 1 Shields Ave., Davis, CA, 95616, USA
| | - Benjamin Z Houlton
- Department of Land, Air, and Water Resources, University of California, Davis, 1 Shields Ave., Davis, CA, 95616, USA
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18
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Winbourne JB, Feng A, Reynolds L, Piotto D, Hastings MG, Porder S. Nitrogen cycling during secondary succession in Atlantic Forest of Bahia, Brazil. Sci Rep 2018; 8:1377. [PMID: 29358584 PMCID: PMC5778002 DOI: 10.1038/s41598-018-19403-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/21/2017] [Indexed: 11/08/2022] Open
Abstract
Carbon accumulation in tropical secondary forests may be limited in part by nitrogen (N) availability, but changes in N during tropical forest succession have rarely been quantified. We explored N cycle dynamics across a chronosequence of secondary tropical forests in the Mata Atlântica of Bahia, Brazil in order to understand how quickly the N cycle recuperates. We hypothesized that N fixation would decline over the course of succession as N availability and N gaseous losses increased. We measured N fixation, KCl-extractable N, net mineralization and nitrification, resin-strip sorbed N, gaseous N emissions and the soil δ15N in stands that were 20, 35, 50, and > 50 years old. Contrary to our initial hypothesis, we found no significant differences between stand ages in any measured variable. Our findings suggest that secondary forests in this region of the Atlantic forest reached pre-disturbance N cycling dynamics after just 20 years of succession. This result contrasts with previous study in the Amazon, where the N cycle recovered slowly after abandonment from pasture reaching pre-disturbance N cycling levels after ~50 years of succession. Our results suggest the pace of the N cycle, and perhaps tropical secondary forest, recovery, may vary regionally.
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Affiliation(s)
- Joy B Winbourne
- The Institute at Brown for Environment and Society, Brown University, Box 1951, Providence, RI, 02912, USA.
| | - Aida Feng
- The Institute at Brown for Environment and Society, Brown University, Box 1951, Providence, RI, 02912, USA
| | - Lovinia Reynolds
- The Institute at Brown for Environment and Society, Brown University, Box 1951, Providence, RI, 02912, USA
| | - Daniel Piotto
- Centro de Formação em Ciências Agroflorestais, Universidade Federal do Sul da Bahia, Ilhéus-BA, Brazil
| | - Meredith G Hastings
- The Institute at Brown for Environment and Society, Brown University, Box 1951, Providence, RI, 02912, USA
- Department of Earth, Environmental, and Planetary Sciences, Brown University, Box 1846, Providence, RI, 02912, USA
| | - Stephen Porder
- The Institute at Brown for Environment and Society, Brown University, Box 1951, Providence, RI, 02912, USA
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19
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Zheng M, Zhang W, Luo Y, Mori T, Mao Q, Wang S, Huang J, Lu X, Mo J. Different responses of asymbiotic nitrogen fixation to nitrogen addition between disturbed and rehabilitated subtropical forests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 601-602:1505-1512. [PMID: 28605868 DOI: 10.1016/j.scitotenv.2017.06.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/03/2017] [Accepted: 06/05/2017] [Indexed: 06/07/2023]
Abstract
Asymbiotic nitrogen (N) fixation is an important source of new N in ecosystems, and is sensitive to atmospheric N deposition. However, there is limited understanding of asymbiotic N fixation and its response to N deposition in the context of forest rehabilitation. In this study, we measured N fixation rates (acetylene reduction) in different ecosystem compartments (i.e. soil, forest floor, moss Syrrhopodon armatus, and canopy leaves) in a disturbed and a rehabilitated subtropical forest in southern China, under 12years of N treatments: control, low N addition (50kgNha-1yr-1), and medium N addition (100kgNha-1yr-1). The rehabilitated forest had higher nutrient (e.g. N) availability than the disturbed forest. In control plots, N fixation rates in forest floor were higher in the rehabilitated forest than in the disturbed forest, but N fixation rates in other compartments (soil, S. armatus, and canopy leaves) were comparable between the forests. Nitrogen addition significantly suppressed N fixation in soil, forest floor, S. armatus, and canopy leaves in the disturbed forest, but had no significant effect on those compartments in the rehabilitated forest. The main reasons for the negative effects of N addition on N fixation in the disturbed forest were NH4+ inhibition (soil), the P and C limitation (forest floor), and the reduced N dependence on canopy N-fixers (S. armatus and canopy leaves). We conclude that asymbiotic N fixation does not decline with increasing N availability after rehabilitation in the study forests. The inhibitory effects of N addition on asymbiotic N fixation occurred in the disturbed forest but not in the rehabilitated forest, indicating that forest rehabilitation may change the response of ecosystem function (i.e. N fixation) to N deposition, which merits further study in other tropical and subtropical regions.
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Affiliation(s)
- Mianhai Zheng
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Wei Zhang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Yiqi Luo
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Taiki Mori
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Qinggong Mao
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Senhao Wang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100039, China
| | - Juan Huang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Xiankai Lu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Jiangming Mo
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
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20
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Brewer SW, Stott GL. A new species of Cinnamomum (Lauraceae) from the Bladen Nature Reserve, southern Belize. PHYTOKEYS 2017; 81:1-10. [PMID: 28785162 PMCID: PMC5523868 DOI: 10.3897/phytokeys.81.13256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 05/17/2017] [Indexed: 06/07/2023]
Abstract
A new species in the Lauraceae, Cinnamomum bladenense S.W. Brewer & G.L. Stott, is described from the Bladen Nature Reserve in southern Belize. The new species is similar to Cinnamomum brenesii (Standl.) Kosterm., from which it differs by its much smaller, narrowly-campanulate flowers, its inner tepals glabrous abaxially, its shorter petioles, its minutely sericeous younger twigs, and its abaxial leaf surfaces not glaucous and with prominent secondary venation. A description, preliminary conservation assessment, and photographs of the species as well as a key to and notes on the Cinnamomum of Belize are provided.
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Affiliation(s)
- Steven W. Brewer
- Belize Foundation for Research and Environmental Education, PO Box 129 Punta Gorda, Belize, Central America
| | - Gail L. Stott
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
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