​RESEARCH

​We address questions about plant responses to the environment across a variable and changing world. Our research focuses primarily on carbon cycling in leaves—respiration and photosynthesis—how these fluxes vary across different settings and different species, and the impact of these changes on the greater ecosystem. 

Ecology examines the interconnectedness of the natural world and how biological processes shift and adapt with the environment. All my research is fundamentally a team endeavor - all studies mentioned below have multiple authors ranging in level from undergraduate to senior scientists and full professors. 

If you are interested in doing research in the lab, please read about the following projects and questions and make an appointment to discuss which might be most interesting to work on! 

Complexity and change in the warming Arctic tundra  

  • The Arctic is the most rapidly warming region on Earth. Warmer temperatures in the winter and summer has led to cascading impacts that reach nearly every element in the tundra ecosystem. My graduate research focused on changes of warming, increased soil nutrient availability, and altered seasonality and their effects on leaf-level carbon cycling in common tundra plant species. Specifically, these studies (Heskel et al. 2012, Heskel et al. 2013, Heskel et al. 2014, Heskel et al. 2014) measured variables of leaf respiration and carbon use that might help explain how woody shrub species are increasingly dominant in a warming tundra. 
  • Current research in the Arctic focuses on a unique tundra landmass - the Yamal Peninsula in Central Siberia. Since 2019, I have been part of an NSF-funded working group to develop integrated ecological research in Yamal. In Summer 2021, the research team was awarded an NSF grant (2022-2027) to study how reindeer migration, Indigenous groups, and shrub growth has been altered due to recent climate change and infrastructure development in the region. These funds will allow me to study shrub and plant diversity across a tundra-type gradient in Yamal with Macalester students. *Due to the war in Ukraine, all field-based research has been suspended indefinitely*.  

How do plants alter their carbon cycling under different environments?

  • Changes in short and long-term temperature and light environments impact how plants photosynthesize and respire through a shift termed 'acclimation'. This can have massive impacts on how carbon is modeled at the ecosystem and global scales. 
  • In previous research, I have studied the short-term temperature response of leaf respiration in plants from around the world (Heskel et al. 2016), and found this response can be represented as a simple model across diverse climates and biomes. 
  • I also research how light can suppress rates of respiration, which can be important to calculate how much carbon is actually being assimilated in ecosystems (Heskel et al. 2013; Heskel and Tang, 2018; Heskel 2018)
  • Recently, I've worked with students at Macalester's Ordway field station to examine how two understory trees vary in their carbon cycling and fluorescence through the growing season. The work we did in summer 2019 is currently under revision in AoB-PLANTS, and includes 5 undergraduate co-authors!

How can we model impacts of historic and future CO2 levels on plant function? 

  • Atmospheric CO2 is rising steadily, now surpassing 420 ppm at its most recent highs. This shift impacts plant form and function, and can also be tracked historically through plant stomata and radiocarbon isotopes. 
  • Current research in my lab, started by Jennings Mergenthal ('21) looks at herbarium specimens and how they have shifted with historic CO2 levels. 
  • I am also interested in radiocarbon as a proxy for fossil fuel emissions in urban plants - work with Elizabeth Hrycyna ('21) has found patterns linked to both species differences and historic redlining in Saint Paul. 
  • There are also opportunities to model and measure future CO2 using FACE experiments at Cedar Creek and SPRUCE, globally famous ecological experiments, both in Minnesota. 

Place-based, student-led research 

  • Undergraduate research and serving as a mentor to novel research ideas is fundamental to my role as a professor at Macalester. Sometimes this means taking a totally new research direction - some examples of how we have incorporated new methods and ideas below:
  • Elizabeth Hrycyna ('21) used satellite data from TROPOMI via Google Earth Engine to examine NO2 variation in US Midwestern cities, and how it might align with historic redlining. This study started as an Honors thesis in Spring 2019, and evolved a lot over time - from a field-based idea, to a database idea, to remote sensing. With support from collaborators Saiido Noor ('23) and Jennings Mergenthal ('21), this study turned into a manuscript that is now published in Elementa as of Summer 2022! 
  • There are open questions for lab members to explore on local, urban ecological issues such as Emerald Ash Borer and shade deficits and temperature impacts, as well as work in global change experiments like Cedar Creek and SPRUCE!