Degree Type

Thesis

Date of Award

2017

Degree Name

Master of Science

Department

Ecology, Evolution, and Organismal Biology

Major

Environmental Science

First Advisor

William G. Crumpton

Abstract

Nitrate loads from agricultural sources raise major water quality concerns for the US Corn Belt. Wetland restoration has been identified as a promising strategy to reduce nonpoint source nitrogen loads from agricultural watersheds. However, there is concern over increased nitrous oxide (N2O) emissions from wetlands subject to elevated nitrogen loads. The major purpose of this research was to quantify N2O and CH4 emissions from wetlands targeted to intercept and reduce nitrate loads in agricultural watersheds. We measured nitrate removal and N2O and CH4 emission rates at three wetlands subject to different nitrate loads. Nitrate loads and losses were estimated based on close interval monitoring of inflows and outflows. N2O and CH4 emissions were estimated using floating chambers during synoptic studies conducted from late spring through early fall in 2015-2016. N2O emission rates averaged 3.5 mg N2O-N m-2 day-1, similar to rates from cropland even though wetlands received more N per area than croplands. N2O emission rates were correlated to nitrate concentrations, loading rates, and loss rates. CH4 emission rates averaged 793 mg CH4 m-2 day-1, similar to rates for restored depressional wetlands in Iowa.

Copyright Owner

Hannah Leigh Hoglund

Language

en

File Format

application/pdf

File Size

27 pages

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