Abstract

Freshwater wetlands are a critical feature of the landscape, providing important ecosystem services such as nutrient removal. However, created wetlands often fail to meet functional performance criteria, frequently due to shortcomings in management of key functional drivers, especially hydrology and soil quality. In natural wetlands, hydrology, carbon (C) and nitrogen (N) availability play an important role in nutrient cycling. However, controls on the relative importance of denitrification and N fixation, and release of the greenhouse gas nitrous oxide (N2O ) are poorly understood in created wetlands. The tradeoff between these processes and the mechanisms for improved management are are imperative to achieving functional equivalence. C addition can potentially alleviate the poor organic matter and nutrient levels in created wetlands that limit biogeochemical processes such as denitrification and N fixation. The goal of this project was to determine how hydrological regime and manipulation of organic matter availability affect N cycling in two created wetlands with differing hydrology in Western New York. Hydrological differences between sites significantly influenced potential denitrification, which was significantly higher at the wetter site. The addition of municipal leaf litter compost as a management technique successfully increased soil organic matter, C, N, and moisture content, promoting a 50% increase in potential denitrification without increasing N2O release. N fixation was not measurable at either site, even with the addition of organic matter. Multiple regression modeling identified different drivers of potential denitrification between sites, with C limiting at the wetter site, and N limiting at the drier site. These results suggest that readily available leaf compost is a viable option to enhance wetland function without also increasing undesirable N2O emissions, but that simultaneous management of hydrology must occur to ensure maximum N removal.

Library of Congress Subject Headings

Constructed wetlands--Ecology; Constructed wetlands--Management; Nitrogen cycle; Hydrology

Publication Date

4-21-2020

Document Type

Thesis

Student Type

Graduate

Degree Name

Environmental Science (MS)

Department, Program, or Center

Thomas H. Gosnell School of Life Sciences (COS)

Advisor

Anna Christina Tyler

Advisor/Committee Member

Carmody McCalley

Advisor/Committee Member

Nathan Eddingsaas

Campus

RIT – Main Campus

Plan Codes

ENVS-MS

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