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Gilmour K, Hoggarth C, Williams C, Baulch HM. Cold spots and cold moments: The potential for sediment freezing to depress denitrification in wetland sediments. JOURNAL OF ENVIRONMENTAL QUALITY 2022; 51:990-1002. [PMID: 35819079 DOI: 10.1002/jeq2.20384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
Within the north-temperate zone, winters can be long and are associated with conditions of low temperature and potential for sediment freezing. There are critical gaps in our knowledge of biogeochemical cycling during winter and inadequate knowledge of how warming winters and changing snowpack might affect biogeochemistry. Here, we assessed the impacts of sediment freeze-thaw cycling and nitrate amendment on denitrification rates in the littoral fringe of four urban wetlands. We demonstrate the potential for experimental sediment freezing to suppress denitrification, although freezing effects were not observed at all sites. Multiple freeze-thaw cycles were assessed, and, although subsequent cycles may affect denitrification, the first instance of our experimental freezing seems the most critical. Although this work demonstrates potential sensitivity of wetland denitrification rates to changing winter conditions, we note nitrate availability has a larger impact upon denitrification rates. This suggests nitrification rates and changing nitrate loads may be more important determinants of nitrate retention than sediment freeze-thaw history. Although there has been great interest in hot spots and moments for biogeochemical cycling, we suggest there is similar need to understand cold spots and moments, as evidenced here. This is particularly important where cold moments may correspond with critical periods of nitrate transport, such as snowmelt.
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Affiliation(s)
- Kimberly Gilmour
- Dep. of Biology, Univ. of Saskatchewan, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada
- Global Institute for Water Security National Hydrology Research Centre, 11 Innovation Blvd, Saskatoon, SK, S7N 3H5, Canada
| | - Cameron Hoggarth
- Global Institute for Water Security National Hydrology Research Centre, 11 Innovation Blvd, Saskatoon, SK, S7N 3H5, Canada
| | - Clayton Williams
- Dep. of Environmental Studies and Science, Saint Michael's College, One Winooski Park, Colchester, VT 05439, USA
| | - Helen M Baulch
- Global Institute for Water Security National Hydrology Research Centre, 11 Innovation Blvd, Saskatoon, SK, S7N 3H5, Canada
- School of Environment and Sustainability, Univ. of Saskatchewan, 117 Science Place, Saskatoon, SK, S7N 5C8, Canada
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Yang Y, Xiao Y, Li C, Wang B, Gao Y, Zhou G. Nitrogen addition, rather than altered precipitation, stimulates nitrous oxide emissions in an alpine steppe. Ecol Evol 2021; 11:15153-15163. [PMID: 34765167 PMCID: PMC8571595 DOI: 10.1002/ece3.8196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 11/25/2022] Open
Abstract
Anthropogenic-driven global change, including changes in atmospheric nitrogen (N) deposition and precipitation patterns, is dramatically altering N cycling in soil. How long-term N deposition, precipitation changes, and their interaction influence nitrous oxide (N2O) emissions remains unknown, especially in the alpine steppes of the Qinghai-Tibetan Plateau (QTP). To fill this knowledge gap, a platform of N addition (10 g m-2 year-1) and altered precipitation (±50% precipitation) experiments was established in an alpine steppe of the QTP in 2013. Long-term N addition significantly increased N2O emissions. However, neither long-term alterations in precipitation nor the co-occurrence of N addition and altered precipitation significantly affected N2O emissions. These unexpected findings indicate that N2O emissions are particularly susceptible to N deposition in the alpine steppes. Our results further indicated that both biotic and abiotic properties had significant effects on N2O emissions. N2O emissions occurred mainly due to nitrification, which was dominated by ammonia-oxidizing bacteria, rather than ammonia-oxidizing archaea. Furthermore, the alterations in belowground biomass and soil temperature induced by N addition modulated N2O emissions. Overall, this study provides pivotal insights to aid the prediction of future responses of N2O emissions to long-term N deposition and precipitation changes in alpine ecosystems. The underlying microbial pathway and key predictors of N2O emissions identified in this study may also be used for future global-scale model studies.
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Affiliation(s)
- Yang Yang
- Northwest Institute of Plateau BiologyChinese Academy of ScienceXiningChina
- University of Chinese Academy of ScienceBeijingChina
| | - Yuanming Xiao
- Northwest Institute of Plateau BiologyChinese Academy of ScienceXiningChina
- University of Chinese Academy of ScienceBeijingChina
| | - Changbin Li
- College of Agriculture and Animal HusbandryQinghai UniversityXiningChina
| | - Bo Wang
- Northwest Institute of Plateau BiologyChinese Academy of ScienceXiningChina
- University of Chinese Academy of ScienceBeijingChina
| | - Yongheng Gao
- Northwest Institute of Plateau BiologyChinese Academy of ScienceXiningChina
- Institute of Mountain Hazards and EnvironmentChinese Academy of ScienceChengduChina
| | - Guoying Zhou
- Northwest Institute of Plateau BiologyChinese Academy of ScienceXiningChina
- Key Laboratory of Tibetan Medicine ResearchChinese Academy of SciencesXiningChina
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Krause SMB, Näther A, Ortiz Cortes V, Mullins E, Kessel GJT, Lotz LAP, Tebbe CC. No Tangible Effects of Field-Grown Cisgenic Potatoes on Soil Microbial Communities. Front Bioeng Biotechnol 2020; 8:603145. [PMID: 33224940 PMCID: PMC7670967 DOI: 10.3389/fbioe.2020.603145] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 10/09/2020] [Indexed: 12/30/2022] Open
Abstract
DNA modification techniques are increasingly applied to improve the agronomic performance of crops worldwide. Before cultivation and marketing, the environmental risks of such modified varieties must be assessed. This includes an understanding of their effects on soil microorganisms and associated ecosystem services. This study analyzed the impact of a cisgenic modification of the potato variety Desirée to enhance resistance against the late blight-causing fungus Phytophthora infestans (Oomycetes) on the abundance and diversity of rhizosphere inhabiting microbial communities. Two experimental field sites in Ireland and the Netherlands were selected, and for 2 subsequent years, the cisgenic version of Desirée was compared in the presence and absence of fungicides to its non-engineered late blight-sensitive counterpart and a conventionally bred late blight-resistant variety. At the flowering stage, total DNA was extracted from the potato rhizosphere and subjected to PCR for quantifying and sequencing bacterial 16S rRNA genes, fungal internal transcribed spacer (ITS) sequences, and nir genes encoding for bacterial nitrite reductases. Both bacterial and fungal communities responded to field conditions, potato varieties, year of cultivation, and bacteria sporadically also to fungicide treatments. At the Dutch site, without annual replication, fungicides stimulated nirK abundance for all potatoes, but with significance only for cisgenic Desirée. In all other cases, neither the abundance nor the diversity of any microbial marker differed between both Desirée versions. Overall, the study demonstrates environmental variation but also similar patterns of soil microbial diversity in potato rhizospheres and indicates that the cisgenic modification had no tangible impact on soil microbial communities.
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Affiliation(s)
- Sascha M B Krause
- Thünen Institute of Biodiversity, Federal Research Institute for Rural Areas, Forestry and Fisheries, Braunschweig, Germany.,Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Astrid Näther
- Thünen Institute of Biodiversity, Federal Research Institute for Rural Areas, Forestry and Fisheries, Braunschweig, Germany
| | - Vilma Ortiz Cortes
- Teagasc Crops, Environmental and Land Use Program, Crop Science Department, Oak Park Crops Research Centre, Carlow, Ireland
| | - Ewen Mullins
- Teagasc Crops, Environmental and Land Use Program, Crop Science Department, Oak Park Crops Research Centre, Carlow, Ireland
| | - Geert J T Kessel
- Plant Research International, Wageningen University & Research, Wageningen, Netherlands
| | - Lambertus A P Lotz
- Plant Research International, Wageningen University & Research, Wageningen, Netherlands
| | - Christoph C Tebbe
- Thünen Institute of Biodiversity, Federal Research Institute for Rural Areas, Forestry and Fisheries, Braunschweig, Germany
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Wang L, Gan Y, Bainard LD, Hamel C, St-Arnaud M, Hijri M. Expression of N-cycling genes of root microbiomes provides insights for sustaining oilseed crop production. Environ Microbiol 2020; 22:4545-4556. [PMID: 32656968 DOI: 10.1111/1462-2920.15161] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/07/2020] [Accepted: 07/09/2020] [Indexed: 11/28/2022]
Abstract
Agricultural production is dependent on inputs of nitrogen (N) whose cycle relies on soil and crop microbiomes. Crop diversification has increased productivity; however, its impact on the expression of microbial genes involved in N-cycling pathways remains unknown. Here, we assessed N-cycling gene expression patterns in the root and rhizosphere microbiomes of five oilseed crops as influenced by three 2-year crop rotations. The first phase consisted of fallow, lentil or wheat, and the second phase consisted of one of five oilseed crops. Expression of bacterial amoA, nirK and nirS genes showed that the microbiome of Ethiopian mustard had the lowest and that of camelina the highest potential for N loss. A preceding rotation phase of lentil significantly increased the expression of nifH gene by 23% compared with wheat and improved nxrA gene expression by 51% with chemical fallow in the following oilseed crops respectively. Lentil substantially increased biological N2 fixation and reduced denitrification in the following oilseed crops. Our results also revealed that most N-cycling gene transcripts are more abundant in the microbiomes associated with roots than with the rhizosphere. The outcome of our investigation brings a new level of understanding on how crop diversification and rotation sequences are related to N-cycling in annual cropping systems.
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Affiliation(s)
- Li Wang
- Institut de Recherche en Biologie Végétale, Université de Montréal and Jardin Botanique de Montréal, Montréal, QC, H1X 2B2, Canada
| | - Yantai Gan
- Swift Current Research and Development Centre, Agriculture and Agri-Food Canada, Swift Current, SK, S9H 3X2, Canada
| | - Luke D Bainard
- Swift Current Research and Development Centre, Agriculture and Agri-Food Canada, Swift Current, SK, S9H 3X2, Canada
| | - Chantal Hamel
- Quebec Research and Development Centre, Agriculture and Agri-Food Canada, Quebec City, QC, G1V 2J3, Canada
| | - Marc St-Arnaud
- Institut de Recherche en Biologie Végétale, Université de Montréal and Jardin Botanique de Montréal, Montréal, QC, H1X 2B2, Canada
| | - Mohamed Hijri
- Institut de Recherche en Biologie Végétale, Université de Montréal and Jardin Botanique de Montréal, Montréal, QC, H1X 2B2, Canada.,AgroBiosciences, Mohammed VI Polytechnic University (UM6P), Lot 660 - Hay Moulay Rachid, Ben Guerir, 43150, Morocco
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Yin M, Gao X, Tenuta M, Gui D, Zeng F. Presence of spring-thaw N 2O emissions are not linked to functional gene abundance in a drip-fertigated cropped soil in arid northwestern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 695:133670. [PMID: 31412304 DOI: 10.1016/j.scitotenv.2019.133670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/26/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
Spring-thaw represents a significant source for nitrous oxide (N2O) emissions from fertilized croplands in temperate regions. In this study, we present surface N2O fluxes, soil-profile N2O concentrations at 5, 15, 30 and 60 cm depths along with the abundance of nitrifiers and denitrifiers over the winter and spring-thaw periods in an arid, drip- fertigated cotton field, which had received spring application of 240 kg N ha-1 as urea alone (Urea), polymer-coated urea (ESN), and urea plus urease and nitrification inhibitors. Nitrous oxide emissions from December to April were generally unaffected by fertilizer treatments with a cumulative average of 186 g N ha-1, accounting for 39% of the annual N2O emissions. Emission peaks occurred at spring-thaw and coincided with increasing soil-profile N2O concentrations at all depths, suggesting the burst in N2O fluxes was due to new N2O production, rather than a physical release of N2O trapped in the soil profiles over winter. The abundance of nitrifier and denitrifier genes changed over the winter and spring-thaw periods but was not affected by fertilizer treatments from the previous spring, suggesting the abundance of N2O-producing microorganism was more controlled by environmental conditions than N sources applied in the previous spring. The daily N2O flux rate from December to April was positively correlated with soil temperature, water-filled pore space, and denitrifying enzyme activity, but not with the gene copy number of AOA, AOB, narG, nirS, nirK and nosZ, indicating that variation in the abundance of these genes was not contributing to the N2O emissions. These results suggest that N2O emissions in spring-thaw are substantial for drip-fertigated croplands in the arid regions and should be considered in the annual budgets. The environmental factors such as soil temperature and moisture are likely more important than the copy-numbers of N2O-producing functional genes in driving the variability in spring-thaw emissions.
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Affiliation(s)
- Mingyuan Yin
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystem, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Cele 848300, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaopeng Gao
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystem, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Cele 848300, China; Department of Soil Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
| | - Mario Tenuta
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Department of Soil Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Dongwei Gui
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystem, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Cele 848300, China
| | - Fanjiang Zeng
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystem, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Cele 848300, China
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