Welcome to the Halvorson Aquatic Ecology lab at the University of Central Arkansas! We study how aquatic ecosystems work and respond to environmental change.
Our work takes us into a variety of aquatic ecosystems across Arkansas ranging from streams, to lakes, to wetlands - and we are often answering questions useful to both managers and the broader scientific community.
Current projects in the lab focus on:
(1) Watershed nutrient and sediment loading into Arkansas reservoirs
(2) Water quality and phytoplankton in urban ponds of Central Arkansas
(3) Ecological stoichiometry of macroinvertebrates and basal resources in forested and agricultural streams
(4) Nutrient cycling and phytoplankton dynamics in reservoirs as related to municipal drinking water treatment
Our work takes us into a variety of aquatic ecosystems across Arkansas ranging from streams, to lakes, to wetlands - and we are often answering questions useful to both managers and the broader scientific community.
Current projects in the lab focus on:
(1) Watershed nutrient and sediment loading into Arkansas reservoirs
(2) Water quality and phytoplankton in urban ponds of Central Arkansas
(3) Ecological stoichiometry of macroinvertebrates and basal resources in forested and agricultural streams
(4) Nutrient cycling and phytoplankton dynamics in reservoirs as related to municipal drinking water treatment
LAB NEWS:
June 2025 - A whole year has passed since our last update, and it has been quite a packed year! Eli Wess successfully defended his MS Thesis last month, and our stalwart lab members Felicia, Haley, and Lydia have all found new, full-time positions doing wonderful work. Tate has made a lot of progress on his thesis project about external loading into Brewer Lake. In May, our lab group attended SFS 2025 in Puerto Rico and I think we had a lot of fun and engaged with good science. Going forward, lab undergraduate Alora is prepping for her summer leaf decomposition experiment, and Kenna and Maleah have been helping us with all kinds of field and laboratory work to support ongoing research.
July 2024 - Summer in the lab has been productive! Our lab group has traveled and presented a lot this summer, including at the SFS meeting in Philadelphia and the Arkansas Agriculture, Forests, and Water Conference in Fayetteville. Eli traveled to Wyoming and processed his hundreds of stream samples for elemental contents, and Haley completed her Brewer Lake sediment nutrient incubation study. Felicia has generated interesting findings on our 104b project to understand phytoplankton production of secondary metabolites. Thanks to our collaborators and student workers for all their help.
April 2024 - Another academic year is closing, and the lab group has achieved so much! Felicia is finishing up teaching a new Phycology course and she has started her USGS 104b research on Brewer Lake; Lydia is writing up her thesis findings to defend; Eli is grinding and analyzing all of his field samples for elemental contents; Haley is planning her summer sediment incubation experiment; and our new undergraduate researchers, Cameron and Bryce, have pursued their own projects! Several of our students successfully presented their results at the CNSM research symposium, and Hal, Felicia, Eli, and Haley will be attending SFS 2024 in Philadelphia this June!
October 2023 - We are wading through the semester and we are thankful to have some cool and wet weather again. Lydia has been working hard to summarize her Brewer Lake monitoring data and quantify external nutrient loading, Eli has been processing his summer samples for elemental contents, and Haley is dreaming up her M.S. thesis project which likely will investigate internal nutrient loading in Brewer Lake. Felicia is teaching General Ecology and wrapping up sample processing from our 2022-2023 urban pond research! Our lab group meetings have discussed work-life balance and subsequent meetings will involve progress updates from the graduate students!
July 2023 - Our lab has been working hard through this hot summer! We have welcomed new graduate student Haley Racioppo and both Eli and Lydia have made great progress on their field and laboratory work. Congratulations to Hal and (especially) Felicia, who received news that our USGS 104b project on algal secondary metabolites has received funding! Felicia recently presented at both the Society for Freshwater Science meeting and the Arkansas Water Resources Conference. Finally, Hal presented a summary of our Brewer Lake project to the Conway Corp Board of Directors.
May 2023 - The spring semester is wrapping up, with a list of accolades for our members! Molly Wozniak won the UCA People's Choice Award for her 3-minute thesis presentation, and undergraduate lab member Emily Walsh won 2nd place in the AURS Science Communication competition during the annual spring research symposium!! We are also super proud of Anthony, Molly, Tyler, and Rachel who are all graduating from UCA this spring. Folks are now transferring their energy into summer research plans.
April 2023 - Congratulations to Molly Wozniak on defending her M.S. thesis, "Macroinvertebrate assemblage responses to land use, water chemistry, and habitat in low-gradient Arkansas streams" and to Anthony Pignatelli for defending his M.S. thesis, "The ecological stoichiometry of food webs in urban streams of Central Arkansas". Both of them did a great job! Thanks to everyone, particularly our whole lab group, for supporting them.
February 2023 - Anthony and Molly are bringing in final data and statistical analyses for their thesis defenses later this spring. Lydia's storm and stream sampling for Brewer Lake are continuing - through the challenges of winter weather! Eli is cementing his research questions and study sites to study aquatic insect stoichiometry. Felicia is fearlessly leading our Freshwater Ecology course, including developing our new lab - and planning multiple STOICH workshops for this year! Our research lab meetings this semester will address inclusivity in ecology, improving our executive functioning skills, providing feedback on research, and much more.
September 2022 - The fall semester is now underway, and what an exhilarating start! Felicia is teaching General Ecology and planning continued pond sampling this Fall. Molly is delving into statistical analysis of her thesis data, which investigates controls of stream macroinvertebrate communities at a wide range of spatial scales. Anthony made a trip to visit our collaborators' labs in Wyoming as he processes his stream food web samples to measure elemental contents. Lydia is keeping up routine Brewer Lake sampling and prepping for storm sampling (...whenever the rain finally comes back?). Hal is teaching Ecology lab and Biology Capstone, prepping for some new grant proposals, and working up some manuscripts for publication. It feels like everyone is well on the way to achieve their semester goals!
July 2022 - The lab's summer field sampling has been in full force, with some projects closing and new ones starting! Molly's summer sampling in south Arkansas low-gradient streams has included sonde deployments, habitat assessments, and fish collections and she is getting close to wrapped-up across all 30 of her sites. Anthony is also close to completing his summer sampling in urban and forested streams, with many resource and macroinvertebrate samples now to prepare for elemental analyses. Felicia started a new field project studying the stoichiometry of phytoplankton in urban ponds, and Lydia also started a new project characterizing external nutrient inputs into Brewer Lake. Our undergraduate team has been so helpful to get it all done! Stay tuned for developments and findings!
May 2022 - The lab group closed up the semester strong - students presented at the CNSM annual research symposium and at the Joint Aquatic Sciences Meeting (JASM) in Grand Rapids, Michigan! See the pictures section for photos of the lab group presenting their posters. Our STOICH project work was also featured in the recent version of UCA Magazine! Everyone is getting ready for summer field work, hopefully with some chances to recharge our batteries, too.
April 2022 - This month has been full of presentation preparation for many in the lab, in anticipation of the UCA CNSM Symposium (April 22nd) and the Joint Aquatic Sciences Meeting in May! Congratulations to summer 2021 REU student Skye Embray, who will be an Instars Fellow at the JASM 2022 meeting in Grand Rapids, Michigan and has also earned a Goldwater Scholarship!! Our research on water quality in South Arkansas was also recently highlighted by UCA news!
March 2022 - Congratulations to lab member Molly Wozniak for successfully defending her Master's prospectus!! She did a great job explaining her work. Molly has also done a great job funding her research from department funding as well as the Audubon Society. She will have a huge dataset on water quality and macroinvertebrate communities in low-gradient streams of south Arkansas. Stay tuned for her initial findings at JASM 2022!
January 2022 - We have welcomed postdoctoral associate Felicia Osburn, who will be teaching and conducting research as part of the EPSCoR STOICH project! Molly has successfully finished her first year of macroinvertebrate sampling and Anthony is closing up his winter sampling. Lydia is working with a great team to process back-logged Brewer Lake samples, too! Somehow amid this, we got our JASM abstracts submitted - and on time! Everyone is working hard. We have an exciting year ahead.
June 2025 - A whole year has passed since our last update, and it has been quite a packed year! Eli Wess successfully defended his MS Thesis last month, and our stalwart lab members Felicia, Haley, and Lydia have all found new, full-time positions doing wonderful work. Tate has made a lot of progress on his thesis project about external loading into Brewer Lake. In May, our lab group attended SFS 2025 in Puerto Rico and I think we had a lot of fun and engaged with good science. Going forward, lab undergraduate Alora is prepping for her summer leaf decomposition experiment, and Kenna and Maleah have been helping us with all kinds of field and laboratory work to support ongoing research.
July 2024 - Summer in the lab has been productive! Our lab group has traveled and presented a lot this summer, including at the SFS meeting in Philadelphia and the Arkansas Agriculture, Forests, and Water Conference in Fayetteville. Eli traveled to Wyoming and processed his hundreds of stream samples for elemental contents, and Haley completed her Brewer Lake sediment nutrient incubation study. Felicia has generated interesting findings on our 104b project to understand phytoplankton production of secondary metabolites. Thanks to our collaborators and student workers for all their help.
April 2024 - Another academic year is closing, and the lab group has achieved so much! Felicia is finishing up teaching a new Phycology course and she has started her USGS 104b research on Brewer Lake; Lydia is writing up her thesis findings to defend; Eli is grinding and analyzing all of his field samples for elemental contents; Haley is planning her summer sediment incubation experiment; and our new undergraduate researchers, Cameron and Bryce, have pursued their own projects! Several of our students successfully presented their results at the CNSM research symposium, and Hal, Felicia, Eli, and Haley will be attending SFS 2024 in Philadelphia this June!
October 2023 - We are wading through the semester and we are thankful to have some cool and wet weather again. Lydia has been working hard to summarize her Brewer Lake monitoring data and quantify external nutrient loading, Eli has been processing his summer samples for elemental contents, and Haley is dreaming up her M.S. thesis project which likely will investigate internal nutrient loading in Brewer Lake. Felicia is teaching General Ecology and wrapping up sample processing from our 2022-2023 urban pond research! Our lab group meetings have discussed work-life balance and subsequent meetings will involve progress updates from the graduate students!
July 2023 - Our lab has been working hard through this hot summer! We have welcomed new graduate student Haley Racioppo and both Eli and Lydia have made great progress on their field and laboratory work. Congratulations to Hal and (especially) Felicia, who received news that our USGS 104b project on algal secondary metabolites has received funding! Felicia recently presented at both the Society for Freshwater Science meeting and the Arkansas Water Resources Conference. Finally, Hal presented a summary of our Brewer Lake project to the Conway Corp Board of Directors.
May 2023 - The spring semester is wrapping up, with a list of accolades for our members! Molly Wozniak won the UCA People's Choice Award for her 3-minute thesis presentation, and undergraduate lab member Emily Walsh won 2nd place in the AURS Science Communication competition during the annual spring research symposium!! We are also super proud of Anthony, Molly, Tyler, and Rachel who are all graduating from UCA this spring. Folks are now transferring their energy into summer research plans.
April 2023 - Congratulations to Molly Wozniak on defending her M.S. thesis, "Macroinvertebrate assemblage responses to land use, water chemistry, and habitat in low-gradient Arkansas streams" and to Anthony Pignatelli for defending his M.S. thesis, "The ecological stoichiometry of food webs in urban streams of Central Arkansas". Both of them did a great job! Thanks to everyone, particularly our whole lab group, for supporting them.
February 2023 - Anthony and Molly are bringing in final data and statistical analyses for their thesis defenses later this spring. Lydia's storm and stream sampling for Brewer Lake are continuing - through the challenges of winter weather! Eli is cementing his research questions and study sites to study aquatic insect stoichiometry. Felicia is fearlessly leading our Freshwater Ecology course, including developing our new lab - and planning multiple STOICH workshops for this year! Our research lab meetings this semester will address inclusivity in ecology, improving our executive functioning skills, providing feedback on research, and much more.
September 2022 - The fall semester is now underway, and what an exhilarating start! Felicia is teaching General Ecology and planning continued pond sampling this Fall. Molly is delving into statistical analysis of her thesis data, which investigates controls of stream macroinvertebrate communities at a wide range of spatial scales. Anthony made a trip to visit our collaborators' labs in Wyoming as he processes his stream food web samples to measure elemental contents. Lydia is keeping up routine Brewer Lake sampling and prepping for storm sampling (...whenever the rain finally comes back?). Hal is teaching Ecology lab and Biology Capstone, prepping for some new grant proposals, and working up some manuscripts for publication. It feels like everyone is well on the way to achieve their semester goals!
July 2022 - The lab's summer field sampling has been in full force, with some projects closing and new ones starting! Molly's summer sampling in south Arkansas low-gradient streams has included sonde deployments, habitat assessments, and fish collections and she is getting close to wrapped-up across all 30 of her sites. Anthony is also close to completing his summer sampling in urban and forested streams, with many resource and macroinvertebrate samples now to prepare for elemental analyses. Felicia started a new field project studying the stoichiometry of phytoplankton in urban ponds, and Lydia also started a new project characterizing external nutrient inputs into Brewer Lake. Our undergraduate team has been so helpful to get it all done! Stay tuned for developments and findings!
May 2022 - The lab group closed up the semester strong - students presented at the CNSM annual research symposium and at the Joint Aquatic Sciences Meeting (JASM) in Grand Rapids, Michigan! See the pictures section for photos of the lab group presenting their posters. Our STOICH project work was also featured in the recent version of UCA Magazine! Everyone is getting ready for summer field work, hopefully with some chances to recharge our batteries, too.
April 2022 - This month has been full of presentation preparation for many in the lab, in anticipation of the UCA CNSM Symposium (April 22nd) and the Joint Aquatic Sciences Meeting in May! Congratulations to summer 2021 REU student Skye Embray, who will be an Instars Fellow at the JASM 2022 meeting in Grand Rapids, Michigan and has also earned a Goldwater Scholarship!! Our research on water quality in South Arkansas was also recently highlighted by UCA news!
March 2022 - Congratulations to lab member Molly Wozniak for successfully defending her Master's prospectus!! She did a great job explaining her work. Molly has also done a great job funding her research from department funding as well as the Audubon Society. She will have a huge dataset on water quality and macroinvertebrate communities in low-gradient streams of south Arkansas. Stay tuned for her initial findings at JASM 2022!
January 2022 - We have welcomed postdoctoral associate Felicia Osburn, who will be teaching and conducting research as part of the EPSCoR STOICH project! Molly has successfully finished her first year of macroinvertebrate sampling and Anthony is closing up his winter sampling. Lydia is working with a great team to process back-logged Brewer Lake samples, too! Somehow amid this, we got our JASM abstracts submitted - and on time! Everyone is working hard. We have an exciting year ahead.
November 2021 - It has been a busy Fall as many of our research projects transition with the seasons and everyone balances their course load! Molly's project is humming well along to collect invertebrates across 20 Gulf Coastal Plains stream sites, Anthony has finalized his field sites and methods to collect intensive stoichiometry data from Arkansas streams, and Lydia will work to complete a thesis based on the Brewer Lake monitoring project. We are all grateful to have the help of awesome undergraduate students Aimee, Peyton, Celeste, Brandy, Noah, Beka, Rachel, and Colton.
July 2021 - M.S. student Tori Hebert successfully defended her thesis, "Land use effects on nutrient limitation, priming effects, and detritivore feeding in a Central Arkansas watershed"! She is moving on to pursue at PhD in Biological Sciences at the University of Alabama in Jon Benstead's lab. Congratulations, Tori!!
June 2021 - Welcome to the lab to our new summer 2021 students! Aimee Dycus and Connor Tolly have joined as undergraduate students on the EPSCoR project, as has Anthony Pignatelli as a new graduate student. We have also welcomed Skye Embray as a summer REU student through the UArk EcoREU program and Willow Newman as a new graduate student, both on the Brewer Lake monitoring project!
April 2021 - It has been an exciting spring in the lab, as we published three female students' first first-authored manuscripts in Freshwater Science, Oikos, and Ecology! All projects started while we were at Southern Miss, and we pushed to publication over this past year. We are so proud to see our students Cheyenne, Taylor, and Tori as they have become published scientists!
February 2021 - We have many new developments in the field as we jump-start Molly's DEQ monitoring project in the Ouachita River watershed, the White Oak Bayou monitoring project in Maumelle, and a leaf decomposition experiment in the Point Remove watershed!
January 2021 - A warm welcome to our new students in the lab this semester! We are particularly excited to have Molly Wozniak join us from Lake Superior State University in Michigan. Molly will be completing her Master's Thesis on macroinvertebrate responses to land use change in Gulf Coastal Plains streams of Arkansas.
November 2020 - Congratulations to lab members Tori and Hunter on earning an Audubon Trust fund grant to support their field research project! They will use the funds to study insects colonizing leaf litter in Arkansas streams varying in land-use intensity, as a follow-up to Tori's M.S. thesis project.
October 2020 - Hal presented a research poster at the virtual meeting of the Great Plains Limnology Conference (GPLC). The poster was titled "Algal influences on litter decomposition across experimental dissolved N and P gradients". See below:
CONTACT INFORMATION:
Dr. Hal Halvorson
Assistant Professor
180 Lewis Science Center
Department of Biology
Conway, AR 72035
email: hhalvorson 'at' uca.edu
Dr. Hal Halvorson
Assistant Professor
180 Lewis Science Center
Department of Biology
Conway, AR 72035
email: hhalvorson 'at' uca.edu
