|
|
Research Interests:
Current Projects:
- Biogeochemistry of streams and rivers
- Impacts of agricultural conservation on nutrient export
- Nitrogen cycling and denitrification in the agricultural landscape
- High-frequency sensor data
Current Projects:
- Watershed monitoring in two agricultural watersheds under cover crop and two-stage ditch conservation practices
- Using sensors to examine storm influence on nitrate export dynamics in agricultural watersheds
- Recovery time of biogeochemical processes, specifically denitrification, following the construction of a two-stage ditch
- Influence substrate and disturbance on hetero- vs. autotrophic nutrient uptake during a five-month algal colonization sequence
- Partitioning autotrophic versus heterotrophic nutrient uptake on varying substrate in experimental streams
- Exploring drivers of nitrous oxide production from incomplete denitrification in streams and rivers
- Determining groundwater influence in a heavily tile-drained agricultural watershed using stable isotopes
- Using a crowdsensing approach to monitor groundwater quality in Northern Indiana
- Hysteresis patterns in turbidity during storms in agricultural watersheds
Education:
Texas Christian University, B.S. in Biology & Spanish (2014, summa cum laude)
University of Arkansas, M.S. in Crop, Soil, & Environmental Sciences (2016)
Publications:
Texas Christian University, B.S. in Biology & Spanish (2014, summa cum laude)
University of Arkansas, M.S. in Crop, Soil, & Environmental Sciences (2016)
Publications:
- Speir, S.L., M.M. Chumchal, R.W. Drenner, W.G. Cocke, M.E. Lewis, and H.J. Whitt. 2014. Methyl mercury and stable istopes of nitrogen reveal that a terrestrial spider has a diet of emergent aquatic insects. Environmental Toxicology and Chemistry. 33(11): 2506-2509.
- Speir, S.L., J.M. Taylor, and J.T. Scott. 2017. Seasonal variation in denitrification in ditch sediments vegetated with rice cutgrass (Leersia oryzoides) across a nitrate gradient. Journal of Environmental Quality. 46(6): 1500-1509.
- A.J. Shogren, J.L. Tank, E.J. Rosi, M.M. Dee, S.L. Speir, D. Bolster, and S.P. Egan. 2019. Transport and instream removal of the Cry1Ab protein from genetically engineered maize is mediated by bioflims in experimental streams. PloS one. 14(5).
- J.M. Taylor, M. Moore, S.L. Speir, S. Testa III. 2020. Vegetated Ditch Habitats Provide Net Nitrogen Sink and Phosphorus Storage Capacity in Agricultural Drainage Networks Despite Senescent Plant Leaching. Water. 12(3).
- S.L. Speir, J.L. Tank, U.H. Mahl. 2020. Quantifying denitrification following floodplain restoration via the two-stage ditch in an agricultural watershed. Ecological Engineering. 155.
- M.T. Trentman, J.L. Tank, T.V. Royer, S.L. Speir, U.H. Mahl, L.R. Sethna. 2020. Cover crops and precipitation influence soluble reactive phosphorus losses via tile drain discharge in an agricultural watershed. Hydrological Processes. 34(23): 4446-4458.
- J.L. Tank, S.L. Speir, L.R. Sethna, T.V. Royer. 2021. The case for studying highly modified agricultural streams: Farming for biogeochemical insights. Limnology and Oceanography Bulletin. https://doi.org/10.1002/lob.10436