Soil Moisture Controls on Spatial and Temporal Patterns of Carbon Dioxide Fluxes in Drylands

Persistent Link:
http://hdl.handle.net/10150/241932
Title:
Soil Moisture Controls on Spatial and Temporal Patterns of Carbon Dioxide Fluxes in Drylands
Author:
Neal, Andrew
Issue Date:
2012
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Dryland ecosystems provide a unique opportunity to study the effects of water limitation on ecosystem activity. The sensitivity of these systems to small inputs of moisture is well-documented, but the expression of water limitation in terms of carbon dioxide flux between the ecosystem and atmosphere remains unclear. Applying a simple conceptual approach to soil moisture dynamics, patterns in carbon flux become clear. Release of carbon dioxide via respiration is primarily driven by moisture in the shallow soil, and differences in respiration rates among plant functional types are only evident after controlling for soil moisture. Alternatively, carbon uptake by a semiarid shrubs ecosystem is largely driven by the availability of deep soil moisture. This link to deep soil moisture improves spatial scaling of gross and net carbon uptake using remote sensing data. Lateral redistribution of moisture on the landscape connects readily observed physical features, namely topography, to ecosystem function, but redistribution is generally not considered in carbon models. A simple runoff scheme coupled to a conceptual model for carbon flux demonstrates the high degree of spatial heterogeneity in carbon dioxide flux resulting from moisture redistribution. The importance of redistribution in carbon modeling is highlighted by interannual variability in modeled carbon fluxes under different rainfall characteristics (event size, event duration, interstorm duration). The links between hydrology and ecology across spatial scales become clearer when topographically-based moisture distribution is used as an organizing variable. In all, this research identifies new avenues for research where moisture dynamics are of central interest in dryland ecohydrology.
Type:
text; Electronic Dissertation
Keywords:
grassland; remote sensing; semiarid ecosystems; shrubland; Hydrology; carbon dioxide flux; ecohydrology
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Hydrology
Degree Grantor:
University of Arizona
Advisor:
Brooks, Paul D.; Papuga, Shirley A.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleSoil Moisture Controls on Spatial and Temporal Patterns of Carbon Dioxide Fluxes in Drylandsen_US
dc.creatorNeal, Andrewen_US
dc.contributor.authorNeal, Andrewen_US
dc.date.issued2012-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractDryland ecosystems provide a unique opportunity to study the effects of water limitation on ecosystem activity. The sensitivity of these systems to small inputs of moisture is well-documented, but the expression of water limitation in terms of carbon dioxide flux between the ecosystem and atmosphere remains unclear. Applying a simple conceptual approach to soil moisture dynamics, patterns in carbon flux become clear. Release of carbon dioxide via respiration is primarily driven by moisture in the shallow soil, and differences in respiration rates among plant functional types are only evident after controlling for soil moisture. Alternatively, carbon uptake by a semiarid shrubs ecosystem is largely driven by the availability of deep soil moisture. This link to deep soil moisture improves spatial scaling of gross and net carbon uptake using remote sensing data. Lateral redistribution of moisture on the landscape connects readily observed physical features, namely topography, to ecosystem function, but redistribution is generally not considered in carbon models. A simple runoff scheme coupled to a conceptual model for carbon flux demonstrates the high degree of spatial heterogeneity in carbon dioxide flux resulting from moisture redistribution. The importance of redistribution in carbon modeling is highlighted by interannual variability in modeled carbon fluxes under different rainfall characteristics (event size, event duration, interstorm duration). The links between hydrology and ecology across spatial scales become clearer when topographically-based moisture distribution is used as an organizing variable. In all, this research identifies new avenues for research where moisture dynamics are of central interest in dryland ecohydrology.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectgrasslanden_US
dc.subjectremote sensingen_US
dc.subjectsemiarid ecosystemsen_US
dc.subjectshrublanden_US
dc.subjectHydrologyen_US
dc.subjectcarbon dioxide fluxen_US
dc.subjectecohydrologyen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineHydrologyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorBrooks, Paul D.en_US
dc.contributor.advisorPapuga, Shirley A.en_US
dc.contributor.committeememberGupta, Hoshin V.en_US
dc.contributor.committeemembervan Leeuwen, Willem J. D.en_US
dc.contributor.committeememberArcher, Steven R.en_US
dc.contributor.committeememberBrooks, Paul D.en_US
dc.contributor.committeememberPapuga, Shirley A.en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.