{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/129585"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/129585","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Characterization of soil moisture legacy controls of nitrous oxide production and reduction in terrestrial soils","abstract":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-05-01","abstract_html":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-05-01","abstract_has_math":false,"creators":["Ooi, Sean Khan"],"institution":"University of Illinois Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Ecol, Evol, Conservation Biol","degree_department":null,"school":null,"contributors":["Yang, Wendy H","Kent, Angela D","Sanford, Robert A","Heath, Katy D"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-04-25","date_published":"2025-04-25","updated_at":"2026-07-22T22:25:05Z","subjects":["nitrous oxide","soil moisture","stable isotopes","drainage class"],"languages":["en","eng"],"rights":["Copyright 2025 Sean Khan Ooi"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/129585","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Yang, Wendy H","Kent, Angela D","Sanford, Robert A","Heath, Katy D"]},{"key":"dc:creator","label":"Author","values":["Ooi, Sean Khan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-04-25","2025-05"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Ecol, Evol, Conservation Biol"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["nitrous oxide","soil moisture","stable isotopes","drainage class"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2025 Sean Khan Ooi"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/129585"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-05-01","The student, Sean Khan Ooi, accepted the attached license on 2025-04-25 at 14:13.","The student, Sean Khan Ooi, submitted this Dissertation for approval on 2025-04-25 at 14:21.","This Dissertation was approved for publication on 2025-04-25 at 15:33.","DSpace SAF Submission Ingestion Package generated from Vireo submission #21989 on 2025-10-19 at 19:16:20","Nitrous oxide (N2O) production and reduction by soil microbes is strongly influenced by soil moisture content, but the legacy effect of long-term soil moisture regimes on these two processes is not well-understood. In my dissertation, I explored how divergent soil moisture legacies can lead to differing N2O emission dynamics under similar contemporary soil moisture conditions, thereby contributing to notoriously high spatial variation in N2O emissions. I also investigated the role of the relative timing of N2O reduction vs. production as a potential microbial response to frequent anoxia exposure through flooding. In my second chapter, I show that microtopography-driven differences in long-term soil moisture regimes can lead to the formation of distinct N2O production and reduction patterns across soil drainage classes, and that these patterns can shift in response to flooding stress. In my third chapter, I examined how drought and subsequent drought recovery change the N2O emission dynamics of soil through the loss of N2O reduction capacity. In my fourth chapter, I present the method development and use-case test of an automated 15N2O pool dilution technique that leverages an automated multiplexer design and laser spectroscopy to achieve high-throughput measurements of simultaneous N2O production and reduction. My dissertation highlights the importance of soil moisture legacies in controlling N2O reduction capacity, which in turn determines N2O emission potential of soils. My research showed that changes to the timing of N2O reduction following anoxia could be a soil microbial community response to frequent anoxia and was highly vulnerable to drought conditions. Finally, my dissertation demonstrates the conceptual need and methodological means for high temporal resolution measurements of N2O production vs. reduction to advance understanding ofN2O emissions."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Characterization of soil moisture legacy controls of nitrous oxide production and reduction in terrestrial soils"]}]}],"canonical_facts":{"dc:contributor":["Yang, Wendy H","Kent, Angela D","Sanford, Robert A","Heath, Katy D"],"dc:creator":["Ooi, Sean Khan"],"dc:date":["2025-04-25","2025-05"],"dc:description":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-05-01","The student, Sean Khan Ooi, accepted the attached license on 2025-04-25 at 14:13.","The student, Sean Khan Ooi, submitted this Dissertation for approval on 2025-04-25 at 14:21.","This Dissertation was approved for publication on 2025-04-25 at 15:33.","DSpace SAF Submission Ingestion Package generated from Vireo submission #21989 on 2025-10-19 at 19:16:20","Nitrous oxide (N2O) production and reduction by soil microbes is strongly influenced by soil moisture content, but the legacy effect of long-term soil moisture regimes on these two processes is not well-understood. In my dissertation, I explored how divergent soil moisture legacies can lead to differing N2O emission dynamics under similar contemporary soil moisture conditions, thereby contributing to notoriously high spatial variation in N2O emissions. I also investigated the role of the relative timing of N2O reduction vs. production as a potential microbial response to frequent anoxia exposure through flooding. In my second chapter, I show that microtopography-driven differences in long-term soil moisture regimes can lead to the formation of distinct N2O production and reduction patterns across soil drainage classes, and that these patterns can shift in response to flooding stress. In my third chapter, I examined how drought and subsequent drought recovery change the N2O emission dynamics of soil through the loss of N2O reduction capacity. In my fourth chapter, I present the method development and use-case test of an automated 15N2O pool dilution technique that leverages an automated multiplexer design and laser spectroscopy to achieve high-throughput measurements of simultaneous N2O production and reduction. My dissertation highlights the importance of soil moisture legacies in controlling N2O reduction capacity, which in turn determines N2O emission potential of soils. My research showed that changes to the timing of N2O reduction following anoxia could be a soil microbial community response to frequent anoxia and was highly vulnerable to drought conditions. Finally, my dissertation demonstrates the conceptual need and methodological means for high temporal resolution measurements of N2O production vs. reduction to advance understanding ofN2O emissions."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/129585"],"dc:language":["en","eng"],"dc:rights":["Copyright 2025 Sean Khan Ooi"],"dc:subject":["nitrous oxide","soil moisture","stable isotopes","drainage class"],"dc:title":["Characterization of soil moisture legacy controls of nitrous oxide production and reduction in terrestrial soils"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Ecol, Evol, Conservation Biol"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:05Z"}