{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/114352"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/114352","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"Exploring the microbe-mediated soil H² sink : a lab-based study of the physiology and related H² consumption of isolates from the Harvard Forest LTER","abstract":"Atmospheric hydrogen (H²) is a secondary greenhouse gas that attenuates the removal of methane (CH⁴) from the atmosphere. The largest and least understood term in the H² biogeochemical cycle, microbe-mediated soil uptake, is responsible for about 80% of Earth's tropospheric H² sink. A recent discovery of the first H²-oxidizing soil microorganism (Streptomyces sp. PCB7) containing a low-threshold, high-affinity NiFe-hydrogenase functional at ambient H² levels (approx. 530 ppb) made it possible to identify a model organism to characterize microbial H²-uptake behavior. In the present research, several strains of Streptomyces containing the high-affinity NiFe-hydrogenase were isolated from the Harvard Forest LTER and used to characterize H² uptake alongside analysis of their life cycles. It was found that containing the gene encoding for the specific hydrogenase predicted H² uptake behavior in the wild Streptomyces strains and also in more distantly related organisms that contained the gene. The H² uptake rates were correlated with the microorganisms' life cycles, reaching a maximal uptake corresponding with spore formation. Understanding how environmental conditions, organismal life cycle, and H² uptake are connected can help reduce the uncertainty in atmospheric models. With the rise of H²-based energy sources and a potential change in the tropospheric concentration of H² , understanding the sources and sinks of this trace gas is important for the future.","abstract_html":"Atmospheric hydrogen (H²) is a secondary greenhouse gas that attenuates the removal of methane (CH⁴) from the atmosphere. The largest and least understood term in the H² biogeochemical cycle, microbe-mediated soil uptake, is responsible for about 80% of Earth's tropospheric H² sink. A recent discovery of the first H²-oxidizing soil microorganism (Streptomyces sp. PCB7) containing a low-threshold, high-affinity NiFe-hydrogenase functional at ambient H² levels (approx. 530 ppb) made it possible to identify a model organism to characterize microbial H²-uptake behavior. In the present research, several strains of Streptomyces containing the high-affinity NiFe-hydrogenase were isolated from the Harvard Forest LTER and used to characterize H² uptake alongside analysis of their life cycles. It was found that containing the gene encoding for the specific hydrogenase predicted H² uptake behavior in the wild Streptomyces strains and also in more distantly related organisms that contained the gene. The H² uptake rates were correlated with the microorganisms' life cycles, reaching a maximal uptake corresponding with spore formation. Understanding how environmental conditions, organismal life cycle, and H² uptake are connected can help reduce the uncertainty in atmospheric models. With the rise of H²-based energy sources and a potential change in the tropospheric concentration of H² , understanding the sources and sinks of this trace gas is important for the future.","abstract_has_math":false,"creators":["Rao, Deepa,Ph.D.Massachusetts Institute of Technology."],"institution":"Massachusetts Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences","school":null,"contributors":[],"advisors":["Laura Meredith and Ron Prinn."],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012","date_published":"2012","updated_at":"2026-07-22T22:21:51Z","subjects":["Earth, Atmospheric, and Planetary Sciences."],"languages":["eng"],"rights":["MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission."],"rights_urls":["http://dspace.mit.edu/handle/1721.1/7582"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1721.1/114352","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Laura Meredith and Ron Prinn."]},{"key":"dc:contributor.department","label":"Department","values":["Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences"]},{"key":"dc:contributor.other","label":"Dc Contributor Other","values":["Massachusetts Institute of Technology. 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They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission."]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://dspace.mit.edu/handle/1721.1/7582"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1721.1/114352"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Thesis: Ph.D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.","Cataloged from PDF version of thesis.","Includes bibliographical references (pages 91-92)."]},{"key":"dc:description.abstract","label":"Abstract","values":["Atmospheric hydrogen (H²) is a secondary greenhouse gas that attenuates the removal of methane (CH⁴) from the atmosphere. The largest and least understood term in the H² biogeochemical cycle, microbe-mediated soil uptake, is responsible for about 80% of Earth's tropospheric H² sink. A recent discovery of the first H²-oxidizing soil microorganism (Streptomyces sp. PCB7) containing a low-threshold, high-affinity NiFe-hydrogenase functional at ambient H² levels (approx. 530 ppb) made it possible to identify a model organism to characterize microbial H²-uptake behavior. In the present research, several strains of Streptomyces containing the high-affinity NiFe-hydrogenase were isolated from the Harvard Forest LTER and used to characterize H² uptake alongside analysis of their life cycles. It was found that containing the gene encoding for the specific hydrogenase predicted H² uptake behavior in the wild Streptomyces strains and also in more distantly related organisms that contained the gene. The H² uptake rates were correlated with the microorganisms' life cycles, reaching a maximal uptake corresponding with spore formation. Understanding how environmental conditions, organismal life cycle, and H² uptake are connected can help reduce the uncertainty in atmospheric models. With the rise of H²-based energy sources and a potential change in the tropospheric concentration of H² , understanding the sources and sinks of this trace gas is important for the future."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["S.B."]},{"key":"dc:title","label":"Title","values":["Exploring the microbe-mediated soil H² sink : a lab-based study of the physiology and related H² consumption of isolates from the Harvard Forest LTER"]}]}],"canonical_facts":{"dc:contributor.advisor":["Laura Meredith and Ron Prinn."],"dc:contributor.department":["Massachusetts Institute of Technology. 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PCB7) containing a low-threshold, high-affinity NiFe-hydrogenase functional at ambient H² levels (approx. 530 ppb) made it possible to identify a model organism to characterize microbial H²-uptake behavior. In the present research, several strains of Streptomyces containing the high-affinity NiFe-hydrogenase were isolated from the Harvard Forest LTER and used to characterize H² uptake alongside analysis of their life cycles. It was found that containing the gene encoding for the specific hydrogenase predicted H² uptake behavior in the wild Streptomyces strains and also in more distantly related organisms that contained the gene. The H² uptake rates were correlated with the microorganisms' life cycles, reaching a maximal uptake corresponding with spore formation. Understanding how environmental conditions, organismal life cycle, and H² uptake are connected can help reduce the uncertainty in atmospheric models. 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