Diazotrophs: An Overlooked Sink of N2O
Abstract The ocean is the second‐largest source of greenhouse gas nitrous oxide (N2O). However, its role as an N2O sink is severely overlooked. N2O fixation by diazotrophs has lately been proposed as a new pathway of N2O consumption. We investigated diazotrophic N2O consumption and examined the anth...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2025-03-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2024GL114117 |
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| author | Himanshu Saxena Shreya Mehta Sipai Nazirahmed Jitender Kumar Sanjeev Kumar Arvind Singh |
| author_facet | Himanshu Saxena Shreya Mehta Sipai Nazirahmed Jitender Kumar Sanjeev Kumar Arvind Singh |
| author_sort | Himanshu Saxena |
| collection | DOAJ |
| description | Abstract The ocean is the second‐largest source of greenhouse gas nitrous oxide (N2O). However, its role as an N2O sink is severely overlooked. N2O fixation by diazotrophs has lately been proposed as a new pathway of N2O consumption. We investigated diazotrophic N2O consumption and examined the anthropogenic influence on N2O dynamics in the coastal northeastern Arabian Sea, a hotspot of N2O emissions. Our findings reveal that relatively unperturbed waters, unlike anthropogenically perturbed waters, are a modest net N2O sink (98 ± 29% saturation), contrary to previous reports. N2O fixation remains active in anthropogenically perturbed waters in contrast to N2 fixation. We additionally provide evidence that the absence of control incubations leads to incorrect fixation rate estimates, further implying that oceanic dark carbon fixation rates might be overestimated. We suggest that N2O fixation not only directly sequesters N2O but may correspond to 0.3 Tg C y−1 of global ocean net primary production. |
| format | Article |
| id | doaj-art-fffe68c851974e86a6496ca989d6486f |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-fffe68c851974e86a6496ca989d6486f2025-08-20T03:52:32ZengWileyGeophysical Research Letters0094-82761944-80072025-03-01526n/an/a10.1029/2024GL114117Diazotrophs: An Overlooked Sink of N2OHimanshu Saxena0Shreya Mehta1Sipai Nazirahmed2Jitender Kumar3Sanjeev Kumar4Arvind Singh5Geosciences Division Physical Research Laboratory Ahmedabad IndiaGeosciences Division Physical Research Laboratory Ahmedabad IndiaGeosciences Division Physical Research Laboratory Ahmedabad IndiaGeosciences Division Physical Research Laboratory Ahmedabad IndiaGeosciences Division Physical Research Laboratory Ahmedabad IndiaGeosciences Division Physical Research Laboratory Ahmedabad IndiaAbstract The ocean is the second‐largest source of greenhouse gas nitrous oxide (N2O). However, its role as an N2O sink is severely overlooked. N2O fixation by diazotrophs has lately been proposed as a new pathway of N2O consumption. We investigated diazotrophic N2O consumption and examined the anthropogenic influence on N2O dynamics in the coastal northeastern Arabian Sea, a hotspot of N2O emissions. Our findings reveal that relatively unperturbed waters, unlike anthropogenically perturbed waters, are a modest net N2O sink (98 ± 29% saturation), contrary to previous reports. N2O fixation remains active in anthropogenically perturbed waters in contrast to N2 fixation. We additionally provide evidence that the absence of control incubations leads to incorrect fixation rate estimates, further implying that oceanic dark carbon fixation rates might be overestimated. We suggest that N2O fixation not only directly sequesters N2O but may correspond to 0.3 Tg C y−1 of global ocean net primary production.https://doi.org/10.1029/2024GL114117N2 fixationN2O fixationgreenhouse gasesprimary productionArabian seaNitrogen cycle |
| spellingShingle | Himanshu Saxena Shreya Mehta Sipai Nazirahmed Jitender Kumar Sanjeev Kumar Arvind Singh Diazotrophs: An Overlooked Sink of N2O Geophysical Research Letters N2 fixation N2O fixation greenhouse gases primary production Arabian sea Nitrogen cycle |
| title | Diazotrophs: An Overlooked Sink of N2O |
| title_full | Diazotrophs: An Overlooked Sink of N2O |
| title_fullStr | Diazotrophs: An Overlooked Sink of N2O |
| title_full_unstemmed | Diazotrophs: An Overlooked Sink of N2O |
| title_short | Diazotrophs: An Overlooked Sink of N2O |
| title_sort | diazotrophs an overlooked sink of n2o |
| topic | N2 fixation N2O fixation greenhouse gases primary production Arabian sea Nitrogen cycle |
| url | https://doi.org/10.1029/2024GL114117 |
| work_keys_str_mv | AT himanshusaxena diazotrophsanoverlookedsinkofn2o AT shreyamehta diazotrophsanoverlookedsinkofn2o AT sipainazirahmed diazotrophsanoverlookedsinkofn2o AT jitenderkumar diazotrophsanoverlookedsinkofn2o AT sanjeevkumar diazotrophsanoverlookedsinkofn2o AT arvindsingh diazotrophsanoverlookedsinkofn2o |