Isotopic insights into organic matter transport and transformation across hydrological interfaces in a temperate forest catchment, Jackson Cadenhead '21
This study aimed to evaluate the use of stable isotope tracers in identifying the age and source of organic carbon within a temperate lacustrine environment. This was conducted through stable isotope (δ13C and δ15N), and radiocarbon (Δ14C) analyses.
This summer I was lucky to be a remote researcher as part of the KINSC Summer Scholars program. Before the Spring 2020 semester went remote at Haverford, I was set up to spend my summer in Montreal researching at McGill University’s Department of Earth and Planetary Sciences. The project I was initially assigned to involved the use of plant and algal lipids to study climate change in the Labrador Sea over the past 7000 years. I had the chance to do some light research on the Greenland Ice Sheet as part of my Fall 2019 semester abroad, so naturally I was excited to be working on another climate proxy study in the Labrador Sea region. In light of the pandemic, my research was suspended, and it wasn’t until late May that I was able to find a new project to work on remotely with my McGill advisor – using isotope tracers to determine the source and age of organic matter in a lake outside Montreal.
The project involved research that had begun in 2017 yet had not seen much development in recent years. While the project was out of my academic comfort zone, I was able to settle into my role in the project thanks to my advisor’s guidance and understanding. By early June I had started remote research. I began working on the study by digesting previous drafts of the project report as well as background papers on soil science and isotopic tracing – two fields I have been on the fringe of as a Geology student but never fully involved in. By the time I found my footing in the science, I got to work doing entry-level data analysis of isotopic data collected from a variety of soil environments from the field of study; samples included leaf litter, top soil, sub soil, lake sediments, algae, as well as stream sediments both up- and downstream from the lake.
Once I had sorted and prepared the data, it was ready to be imported into MATLAB – a program I had never used before. Once again, I felt out of my comfort zone, though I recognized this as another opportunity to learn. It was in these moments that my advisor’s patience meant a lot to me. We both recognized that it was not the project we thought we would be working on that summer, and as a result we both anticipated there would be a learning curve. Over the remaining weeks of my research I was able to finalize my data analysis in MATLAB. Most of the work I did involved writing script to plot various selections of isotopic data in both two and three dimensions. In doing so, I began to understand how certain isotopic sources were grouped, and what that meant for the transport and age of sediment sources passing through this lacustrine system. By the end of my program I produced three final plots with convex hull groupings to establish the relationship between significant sediment sources, as well as determine outliers in the system which might illuminate less understood transport pathways or biodegradation processes. I hope to continue helping with this project as it enters its later stages.