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Towards Understanding Dissolved Organic Carbon Dynamics at the Intersection of Anthropogenic Modifications and Natural Processes of a Dryland River
Author Info
Wise, Julia L
ORCID® Identifier
http://orcid.org/0000-0002-7302-8421
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470753635
Abstract Details
Year and Degree
2016, PhD, University of Cincinnati, Arts and Sciences: Geology.
Abstract
Dissolved organic carbon (DOC) is a critical nutrient in aquatic ecosystems, but can also be a pollutant in drinking water. Controlled by a combination of catchment wide and instream processes, the bioavailability, reactivity, and concentration of DOC is readily altered by natural and anthropogenic processes within rivers and the greater watershed area. However, little is known about natural or anthropogenic controls on DOC in dryland areas where water resources are limited and increasingly endangered. To address this, we examined the major contributors of DOC within and to a dryland river—the Middle Rio Grande (MRG) in central New Mexico. This was achieved via synoptic sampling of storm event flow in an urban storm drainage system, water in agricultural conveyances, and monthly sampling of the mainstem. We measured DOC concentration, determined its source (terrestrial or instream), and explored its chemical structure (aliphatic v. aromatic) as an indicator of lability. We found that during storm events, DOC entering the river from the storm drainage system is derived from a combination of terrestrial and instream sources. The connection of the landscape to the river via storm event runoff controls when during the storm event DOC from these two sources reaches the river. We found that the agricultural system is a net DOC sink because of water loss during irrigation. The agricultural irrigation system also acts a biogeochemical hotspot where DOC is rapidly cycled. As a result labile DOC is introduced in the agricultural system’s conveyances and DOC effluent from the agricultural systems is more labile and bioavailable than DOC in the mainstem. Within the Middle Rio Grande, we find that despite the addition of DOC from storms and agricultural systems, DOC concentration and character remains largely consistent over time and as the river moves north to south. Additionally, in the MRG DOC concentration is uncoupled from discharge. Thus, we hypothesize that anthropogenic modifications of the watershed and river increase the amount of labile DOC and drive DOC concentration, overriding the influence of natural processes such as discharge. The results of this dissertation provide a framework to understand the competing influences of natural processes and anthropogenic alteration on DOC concentration, source, and character. This framework can guide future research in water treatment and reuse and nutrient dynamics in dryland regions.
Committee
Aaron Diefendorf, Ph.D. (Committee Chair)
Thomas Lowell, Ph.D. (Committee Member)
J Barry Maynard, Ph.D. (Committee Member)
David Byer Nash, Ph.D. (Committee Member)
Jodi Shann, Ph.D. (Committee Member)
Pages
112 p.
Subject Headings
Geochemistry
Keywords
Dissolved Organic Carbon
;
Storm Event
;
Agriculture
;
Dryland River
;
Middle Rio Grande
;
Nutrient Dynamics
Recommended Citations
Refworks
EndNote
RIS
Mendeley
Citations
Wise, J. L. (2016).
Towards Understanding Dissolved Organic Carbon Dynamics at the Intersection of Anthropogenic Modifications and Natural Processes of a Dryland River
[Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470753635
APA Style (7th edition)
Wise, Julia.
Towards Understanding Dissolved Organic Carbon Dynamics at the Intersection of Anthropogenic Modifications and Natural Processes of a Dryland River.
2016. University of Cincinnati, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470753635.
MLA Style (8th edition)
Wise, Julia. "Towards Understanding Dissolved Organic Carbon Dynamics at the Intersection of Anthropogenic Modifications and Natural Processes of a Dryland River." Doctoral dissertation, University of Cincinnati, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470753635
Chicago Manual of Style (17th edition)
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Document number:
ucin1470753635
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Copyright Info
© 2016, some rights reserved.
Towards Understanding Dissolved Organic Carbon Dynamics at the Intersection of Anthropogenic Modifications and Natural Processes of a Dryland River by Julia L Wise is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Cincinnati and OhioLINK.