Carbon dioxide, methane, and nitrous oxide fluxes from managed aquatic systems of the Rio Grande Valley

Author

Siena Rose Stassi, The University of Texas Rio Grande Valley

Date of Award

5-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Agricultural, Environmental, and Sustainability Sciences

First Advisor

Jude A. Benavides

Second Advisor

Rafael M. Almeida

Third Advisor

Chu-Lin Cheng

Abstract

Greenhouse gas (GHG) dynamics from small-scale inland water remain relatively understudied, with knowledge gaps across ecosystem types and regions. In South Texas, there is a unique system of managed distributaries and their associated ox-bow lakes, commonly known as resacas. Most resacas are artificially managed and considered novel ecosystems, yet their GHG dynamics are unknown. Two resaca systems were monitored throughout one year to understand the magnitude, temporal variation, and environmental drivers of diffusive fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), along with ebullitive CH4 emissions. Emissions of both CO2 and CH4 peaked in hot summer months, whereas N2O remained negligible throughout the study. Despite high nutrient and chlorophyll concentrations, CH4 emissions were low year-round compared to other inland waters, likely due to high salinity levels in these systems. CO2 emission rates were high overall, comparable to those from polluted urban waterbodies. Overall GHG emissions were higher in the more stagnant resaca. These findings highlight the distinct GHG dynamics of South Texas resacas and contribute novel insights into the functioning of novel aquatic ecosystems in dryland regions.

Comments

Copyright 2025 Siena Rose Stassi. https://proquest.com/docview/3240623851

Recommended Citation

Stassi, S. R. (2025). Carbon Dioxide, Methane, and Nitrous Oxide Fluxes From Managed Aquatic Systems of the Rio Grande Valley [Master's thesis, The University of Texas Rio Grande Valley]. ScholarWorks @ UTRGV. https://scholarworks.utrgv.edu/etd/1711