Direct biological fixation provides a freshwater sink for N2O
Direct biological fixation provides a freshwater sink for N2O
 
  Nitrous oxide (N2O) is a potent climate gas, with its strong warming potential and ozone-depleting properties both focusing research on N2O sources. Although a sink for N2O through biological fixation has been observed in the Pacific, the regulation of N2O-fixation compared to canonical N2-fixation is unknown. Here we show that both N2O and N2 can be fixed by freshwater communities but with distinct seasonalities and temperature dependencies. N2O fixation appears less sensitive to temperature than N2 fixation, driving a strong sink for N2O in colder months. Moreover, by quantifying both N2O and N2 fixation we show that, rather than N2O being first reduced to N2 through denitrification, N2O fixation is direct and could explain the widely reported N2O sinks in natural waters. Analysis of the nitrogenase (nifH) community suggests that while only a subset is potentially capable of fixing N2O they maintain a strong, freshwater sink for N2O that could be eroded by warming.
Denitrification, Fresh Water, N fixation, Nitrous Oxide
  
  
  
    
      Si, Yueyue
      
        da0cbb1d-cec8-426a-b537-4c7d4e2c1ef0
      
     
  
    
      Zhu, Yizhu
      
        6995b9bf-9ce4-46df-830f-a272a50f758f
      
     
  
    
      Sanders, Ian
      
        a7d8a79d-62f6-4df1-a008-209e6425ce51
      
     
  
    
      Kinkel, Dorothee B.
      
        da216405-ef29-4997-9678-2fc96a8f78a0
      
     
  
    
      Purdy, Kevin J.
      
        e23c9bcc-e26f-4e81-92f1-9cd80b5ee120
      
     
  
    
      Trimmer, Mark
      
        c5d8598a-d7a3-411f-a380-80498066d88c
      
     
  
  
   
  
  
    
    
  
    
    
  
    
      December 2023
    
    
  
  
    
      Si, Yueyue
      
        da0cbb1d-cec8-426a-b537-4c7d4e2c1ef0
      
     
  
    
      Zhu, Yizhu
      
        6995b9bf-9ce4-46df-830f-a272a50f758f
      
     
  
    
      Sanders, Ian
      
        a7d8a79d-62f6-4df1-a008-209e6425ce51
      
     
  
    
      Kinkel, Dorothee B.
      
        da216405-ef29-4997-9678-2fc96a8f78a0
      
     
  
    
      Purdy, Kevin J.
      
        e23c9bcc-e26f-4e81-92f1-9cd80b5ee120
      
     
  
    
      Trimmer, Mark
      
        c5d8598a-d7a3-411f-a380-80498066d88c
      
     
  
       
    
 
  
    
      
  
  
  
  
  
  
    Si, Yueyue, Zhu, Yizhu, Sanders, Ian, Kinkel, Dorothee B., Purdy, Kevin J. and Trimmer, Mark
  
  
  
  
   
    (2023)
  
  
    
    Direct biological fixation provides a freshwater sink for N2O.
  
  
  
  
    Nature Communications, 14 (1), [6775].
  
   (doi:10.1038/s41467-023-42481-2). 
  
  
   
  
  
  
  
  
   
  
    
    
      
        
          Abstract
          Nitrous oxide (N2O) is a potent climate gas, with its strong warming potential and ozone-depleting properties both focusing research on N2O sources. Although a sink for N2O through biological fixation has been observed in the Pacific, the regulation of N2O-fixation compared to canonical N2-fixation is unknown. Here we show that both N2O and N2 can be fixed by freshwater communities but with distinct seasonalities and temperature dependencies. N2O fixation appears less sensitive to temperature than N2 fixation, driving a strong sink for N2O in colder months. Moreover, by quantifying both N2O and N2 fixation we show that, rather than N2O being first reduced to N2 through denitrification, N2O fixation is direct and could explain the widely reported N2O sinks in natural waters. Analysis of the nitrogenase (nifH) community suggests that while only a subset is potentially capable of fixing N2O they maintain a strong, freshwater sink for N2O that could be eroded by warming.
         
      
      
        
          
            
  
    Text
 s41467-023-42481-2
     - Version of Record
   
  
  
    
  
 
          
            
          
            
           
            
           
        
        
       
    
   
  
  
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      Accepted/In Press date: 12 October 2023
 
    
      e-pub ahead of print date: 25 October 2023
 
    
      Published date: December 2023
 
    
  
  
    
  
    
     
        Additional Information:
        Funding Information:
This study was supported through a PhD Studentship from Queen Mary University of London and additionally by the Leverhulme Trust (RPG-2019-008) to M.T. We thank M. Rouen for designing and installing the warming and data-logging system for the ponds, W. Beaumont for providing the on-site wind speed data, and J. Pretty for routine maintenance of the ponds.
Publisher Copyright:
© 2023, Springer Nature Limited.
      
    
  
    
  
    
  
    
  
    
     
        Keywords:
        Denitrification, Fresh Water, N fixation, Nitrous Oxide
      
    
  
    
  
    
  
  
  
    
  
  
        Identifiers
        Local EPrints ID: 484395
        URI: http://eprints.soton.ac.uk/id/eprint/484395
        
          
        
        
        
          ISSN: 2041-1723
        
        
          PURE UUID: 82732b3e-28f2-412d-b947-4430981143c1
        
  
    
        
          
            
              
            
          
        
    
        
          
        
    
        
          
        
    
        
          
        
    
        
          
        
    
        
          
        
    
  
  Catalogue record
  Date deposited: 16 Nov 2023 11:47
  Last modified: 06 Jun 2024 02:17
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      Contributors
      
          
          Author:
          
            
              
              
                Yueyue Si
              
              
                 
              
            
            
          
         
      
          
          Author:
          
            
            
              Yizhu Zhu
            
          
        
      
          
          Author:
          
            
            
              Ian Sanders
            
          
        
      
          
          Author:
          
            
            
              Dorothee B. Kinkel
            
          
        
      
          
          Author:
          
            
            
              Kevin J. Purdy
            
          
        
      
          
          Author:
          
            
            
              Mark Trimmer
            
          
        
      
      
      
    
  
   
  
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