This past fall my research group began a study to investigate the role of erosion and overwash in determining whether freshwater wetlands in the Great Lakes are carbon sinks or sources. Katie Braun, a student in my research group, is tackling a portion of this work for her senior thesis at Northwestern University. Katie is exploring whether a fringing wetland along Lake Michigan is presently functioning as a carbon sink or source and what the likely future of carbon storage is at this site. Her study site is at Illinois Beach State Park, which is located approximately 40 miles north of Chicago, and is a high priority conservation area given that it contains the last remaining stretches of natural shoreline within the Chicago metropolitan region. Katie is using a combination of sedimentological analyses, geomorphic change mapping, and numerical modeling to quantify carbon storage at this wetland and evaluate the impacts of geomorphic change on the present and future carbon budget. In October, we collected a series of cores along the wetland to quantify the amount of carbon stored in the wetland as well as its age. Throughout the fall, we have used an RTK-GPS to map shoreline change as well as the extent of lake overwash. Katie will be busy this winter analyzing core samples and refining the numerical model used to derive present and future carbon budgets. Stay tuned for more updates on the progress of this research!
Below are some photos from our field work this fall:
View of our wetland study site at Illinois Beach State Park. Erosion of wetland peat can be seen at the shoreline. The sand body in the left of the image is a washover deposit that has buried a portion of the wetland.
Katie collecting a core of the wetland. This particular core will be used to determine the age and composition of the wetland material that is eroding into Lake Michigan.
The fruits of our labor. Wetland cores awaiting sampling.