Khatiwada4, Kabi Raj

Klauss, Niklas

Masri, Bassil El

Miles, Marissa

Moon, Jessica B.

Ross, Skylar

Runkle, Benjamin R. K.

Stinchcomb, Gary

English

University of Kentucky

University of Kentucky UKnowledge Kentucky Water Resources Annual Symposium 2023 Kentucky Water Resources Annual Symposium Sep 15th, 10:40 AM Measuring the Contribution of Bald Cypress “Knees” to Greenhouse Gas Emissions During Climate Extremes Skylar Ross Murray State University Jessica B. Moon Murray State University, 1jmoon8@murraystate.edu Niklas Klauss Murray State University Marissa Miles Murray State University Kabi Raj Khatiwada4 University of Arkansas See next page for additional authors Right click to open a feedback form in a new tab to let us know how this document benefits you. Follow this and additional works at: https://uknowledge.uky.edu/kwrri_proceedings  Part of the Engineering Commons, Life Sciences Commons, and the Physical Sciences and Mathematics Commons Ross, Skylar; Moon, Jessica B.; Klauss, Niklas; Miles, Marissa; Khatiwada4, Kabi Raj; Masri, Bassil El; Stinchcomb, Gary; and Runkle, Benjamin R. K., "Measuring the Contribution of Bald Cypress “Knees” to Greenhouse Gas Emissions During Climate Extremes" (2023). Kentucky Water Resources Annual Symposium. 2. https://uknowledge.uky.edu/kwrri_proceedings/2023/event/2 This Presentation is brought to you for free and open access by the Kentucky Water Research Institute at UKnowledge. It has been accepted for inclusion in Kentucky Water Resources Annual Symposium by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. Presenter Information Skylar Ross, Jessica B. Moon, Niklas Klauss, Marissa Miles, Kabi Raj Khatiwada4, Bassil El Masri, Gary Stinchcomb, and Benjamin R. K. Runkle This presentation is available at UKnowledge: https://uknowledge.uky.edu/kwrri_proceedings/2023/event/2 SESSION 1A: CLIMATE 14  Measuring the Contribution of Bald Cypress “Knees” to Greenhouse Gas Emissions During Climate Extremes*   Skylar Ross2,3, Jessica B. Moon1,2, Niklas Klauss1, Marissa Miles1,2, Kabi Raj Khatiwada4, Bassil El Masri2,3, Gary Stinchcomb5, Benjamin R. K. Runkle4  1 Department of Biological Sciences, Murray State University 2The Watershed Studies Institute, Murray State University 3Department of Earth and Environmental Sciences, Murray State University 4Department of Biological and Agricultural Engineering, University of Arkansas 5Department of Earth Sciences, University of Memphis 2,3sross10@murraystate.edu   Bottomland hardwood forest soils and vegetation can be significant sources of greenhouse gasses, such as carbon dioxide (CO2) and methane (CH4), to the atmosphere, but these dynamics are subject to change given increasing global climate extremes. Little is known about the role of aboveground woody root structures (“knees”) of Taxodium distichum (Bald cypress) trees in these carbon dynamics. We are investigating the contribution of knees to bottomland hardwood forest source-sink dynamics of CH4 and CO2. We measured CO2 and CH4 fluxes from individual knees, soils, and 1 m2 plots of combined knees and soil that varied in knee density. Measurements were collected within Dunn Slough of Clarks River National Wildlife Refuge during moderate-to-severe drought conditions in the Fall of 2022 and during non-drought conditions in the Spring of 2023. In drought conditions, we expect aerobic soils to limit the production of CH4 (methanogenesis), and convert soil and woody surfaces to sinks through enhanced opportunities for CH4 oxidation (methanotrophy). While soils did act as CH4 sinks, individual knees were still CH4 sources. Knee emissions also increased with soil (p-value < 0.001) and air (p-value = 0.002) temperatures. Within the 1 m2 plots, there was no effect of knee density on net CH4 uptake; soils in high knee density plots tended to have higher CH4 uptake (not statistically significant, p-value = 0.476), but there were also more knees available for emissions. Soil CO2 emissions increased in plots with high knee densities (p-value = 0.037), potentially due to increased root respiration. Similar to CH4, there was no effect of knee density on CO2 emissions. We are currently investigating whether increases in soil CO2 emissions are being counterbalanced by potential photosynthetic organisms unaccounted for within the plot (e.g., bryophytes and algal crusts). During Spring of 2023, all sampled knees had higher CH4 emissions following a rain event, however it was only significant in the knees located in a side channel (p-value = 0.03), and not those located in the main channel (p-value = 0.15). Comparison between drought and non-drought conditions showed three knees in the main channel emitting on average ~ 139x higher levels of CH4 , though the overall change in the channel was not significant (p-value = 0.09). Sampling is ongoing to see if this pattern holds. Results from this study can be used to improve our understanding of wetland greenhouse gas dynamics in changing climatic extremes.      *This presentation is based upon work supported by the U.S. Geological Survey under Grant/Cooperative Agreement No. G21AP10631-01, WRRA 104B Annual Grant Program. 

Measuring the Contribution of Bald Cypress “Knees” to Greenhouse Gas Emissions During Climate Extremes

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1153&context=kwrri_proceedings

Measuring the Contribution of Bald Cypress “Knees” to Greenhouse Gas Emissions During Climate Extremes

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