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Methane and Nitrous Oxide Fluxes from Water, Plants, and Soils of a Constructed Treatment Wetland in Phoenix, AZ.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Methane and Nitrous Oxide Fluxes from Water, Plants, and Soils of a Constructed Treatment Wetland in Phoenix, AZ./
Author:	Ramos-Holguin, Jorge.
Description:	1 online resource (150 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 78-10(E), Section: B.
Subject:	Ecology. -
Online resource:	click for full text (PQDT)
ISBN:	9781369790214

Methane and Nitrous Oxide Fluxes from Water, Plants, and Soils of a Constructed Treatment Wetland in Phoenix, AZ.
Ramos-Holguin, Jorge.

Methane and Nitrous Oxide Fluxes from Water, Plants, and Soils of a Constructed Treatment Wetland in Phoenix, AZ. - 1 online resource (150 pages)

Source: Dissertation Abstracts International, Volume: 78-10(E), Section: B.

Thesis (Ph.D.)--Arizona State University, 2017.

Includes bibliographical references

Constructed treatment wetlands (CTW) have been a cost-efficient technological solution to treat different types of wastewater but may also be sources of emitters of methane (CH4) and nitrous oxide (N2O). Thus, my objective for this dissertation was to investigate CH4 and N 2O fluxes via multiple pathways from the Tres Rios CTW located in Phoenix, AZ, USA. I measured gas fluxes from the CTW along a whole-system gradient (from inflow to outflow) and a within-marsh gradient (shoreline, middle, and open water sites). I found higher diffusive CH4 release in the summer compared to spring and winter seasons. Along the whole-system gradient, I found greater CH4 and N2O emission fluxes near the inflow compared to near the outflow. Within the vegetated marsh, I found greater CH4 emission fluxes at the vegetated marsh subsites compared to the open water. In contrast, N2O emissions were greater at the marsh-open water locations compared to interior marsh. To study the plant-mediated pathway, I constructed small gas chambers fitted to Typha spp. leaves. I found plant-mediated CH4 fluxes were greater near the outflow than near the inflow and that CH4 fluxes were higher from lower sections of plants compared to higher sections. Overall, Typha spp. emitted a mean annual daily flux rate of 358.23 mg CH 4 m-2 d-1. Third, using a 30-day mesocosm experiment I studied the effects of three different drydown treatments (2, 7, 14 days) on the fluxes of CH4 and N2O from flooded CTW soils. I found that CH4 fluxes were not significantly affected by soil drydown events. Soils that were dry for 7 days shifted from being N2O sources to sinks upon inundation. As a result, the 7-day drydown soils were sinks while the 14-day drydown soils showed significant N2O release. My results emphasize the importance of studying ecological processes in CTWs to improve their design and management strategies so we can better mitigate their greenhouse gas emissions.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781369790214Subjects--Topical Terms:

575279
Ecology.
Index Terms--Genre/Form:

554714
Electronic books.

Methane and Nitrous Oxide Fluxes from Water, Plants, and Soils of a Constructed Treatment Wetland in Phoenix, AZ.
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100 1 $a Ramos-Holguin, Jorge. $3 1184672
245 1 0 $a Methane and Nitrous Oxide Fluxes from Water, Plants, and Soils of a Constructed Treatment Wetland in Phoenix, AZ.
264 0 $c 2017
300 $a 1 online resource (150 pages)
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500 $a Source: Dissertation Abstracts International, Volume: 78-10(E), Section: B.
500 $a Adviser: Daniel L. Childers.
502 $a Thesis (Ph.D.)--Arizona State University, 2017.
504 $a Includes bibliographical references
520 $a Constructed treatment wetlands (CTW) have been a cost-efficient technological solution to treat different types of wastewater but may also be sources of emitters of methane (CH4) and nitrous oxide (N2O). Thus, my objective for this dissertation was to investigate CH4 and N 2O fluxes via multiple pathways from the Tres Rios CTW located in Phoenix, AZ, USA. I measured gas fluxes from the CTW along a whole-system gradient (from inflow to outflow) and a within-marsh gradient (shoreline, middle, and open water sites). I found higher diffusive CH4 release in the summer compared to spring and winter seasons. Along the whole-system gradient, I found greater CH4 and N2O emission fluxes near the inflow compared to near the outflow. Within the vegetated marsh, I found greater CH4 emission fluxes at the vegetated marsh subsites compared to the open water. In contrast, N2O emissions were greater at the marsh-open water locations compared to interior marsh. To study the plant-mediated pathway, I constructed small gas chambers fitted to Typha spp. leaves. I found plant-mediated CH4 fluxes were greater near the outflow than near the inflow and that CH4 fluxes were higher from lower sections of plants compared to higher sections. Overall, Typha spp. emitted a mean annual daily flux rate of 358.23 mg CH 4 m-2 d-1. Third, using a 30-day mesocosm experiment I studied the effects of three different drydown treatments (2, 7, 14 days) on the fluxes of CH4 and N2O from flooded CTW soils. I found that CH4 fluxes were not significantly affected by soil drydown events. Soils that were dry for 7 days shifted from being N2O sources to sinks upon inundation. As a result, the 7-day drydown soils were sinks while the 14-day drydown soils showed significant N2O release. My results emphasize the importance of studying ecological processes in CTWs to improve their design and management strategies so we can better mitigate their greenhouse gas emissions.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Ecology. $3 575279
650 4 $a Environmental science. $3 1179128
650 4 $a Soil sciences. $3 1179645
655 7 $a Electronic books. $2 local $3 554714
690 $a 0329
690 $a 0768
690 $a 0481
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a Arizona State University. $b Biology. $3 1184673
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10276114 $z click for full text (PQDT)