While drifting among the low hanging branches that hang along the bank of any river, it’s easy to believe that the the world isn’t so scarred by the mistakes of our species. When basking in the fleeting sun of a Midwest summer you could forget, absolutely, the complete desecration that has ensued along the Illinois River and other river’s like it, for more than 170 years. Even as fall and winter descend upon the region we call home, few of us consider the impact our modern lifestyle generates. We hide behind sanitized and insulated walls, going about our daily lives without a thought to one our most impactful resources; the river system.
However, a few of our state’s residents have undertaken the nearly insurmountable task of understanding exactly what our impact on these finely tuned and highly kinetic resources have been. Dr. Andrea Fritts of the Illinois Natural History Survey (INHS) and her team of dedicated researchers, have selected three specific areas of study in an effort to further understand these impacts. Each of these three focuses take an advanced chemical look at one incredible group of animals, and what their durable outer tissues can narrate to the modern world.
Freshwater Mussels, which are comprised of a soft tissue inner body and a hard, calcium carbonate outer shell, are essential to the maintenance and health of the river systems that they inhabit.
To simplify their function, mussels live in the substrate of the river just on top of the riverbed. This enables them to siphon bacteria, algae and other particulates out of the water [1]. The siphoning action they carry out functions effectively as food source for mussels, but also as a filtration mechanism for the water within their habitat. Dr. Fritts has said, “One thing that I always try to convey to the public is that freshwater mussels provide an important service by naturally filtering and cleaning our nation’s waters. This means that healthy mussel populations reduce the amount of treatment that is necessary to make river and lake water safe for drinking and reduces the cost of the overall treatment process.”
As these mussels grow, their shell must also grow to accommodate the larger specimen. When this process occurs calcium carbonate is produced in layers underneath the existing shell. Often, organic compounds and heavy metals react with the calcium carbonate to create a lasting record of environmental conditions locked within the hard tissue’s chemical makeup.
Photo Courtesy of Alba Ecology, Ecological Consultancy [2]
In one of the three project divisions that Dr. Andrea Fritts is is studying, in partnership with Dr. Wendell Haag- U.S. Forest Service and Dr. Andrew Rypel-Wisconsin DNR, the researchers are able to identify the stable isotope compounds present within the the hard tissue of shell in four species of freshwater mussel on the Illinois River. By analyzing specimens that have been collected and stored for up to 140 years by the INHS (Illinois Natural History Survey), the researchers will have a nearly complete and incredibly detailed historical record of environmental factors that were present at the time the mussel was creating each additional layer. This process, called ablation, could track even small changes in the mussel’s environment.
To further understand environmental change and some of it’s anthropologic causes, Dr. Fritts has established a second aspect of research dubbed, “The Legacy Project”. Dr Fritts has teamed up with scholars, Dr. Aaron Shoults-Wilson of the Roosevelt University in Chicago, Dr. Robert Warren- Illinois State Museum in Springfield, and Dr. Jason Unrine of the University of Kentucky for this portion of her work. Within the legacy project, Andrea hopes to use the same type of hard tissue from the mussels of the Illinois River to identify heavy metal contaminants that were present in the specimen’s environment before its collection. These heavy metals can include lead, mercury, and chromium among other reactive isotopes.
This vital timeline could encompass many great changes in industry, agriculture, and society. By having an inclusive documentation of such large shifts of the Illinois Watershed usage, the researchers may also have a more complete picture of the anthropological effect on our nation’s, and certainly Illinois’, rivers. When asked why she was moved to research these topics in such great depth, Andrea replied, “I was inspired to work on this project after learning about the incredible historic resource of mussel shells that were available through the Illinois Natural History (INHS) Survey Mollusk Collection. We are so fortunate to have such a strong historic emphasis on the natural resources of Illinois—the INHS is over 150 years years old and we have an unprecedented opportunity to study how anthropogenic actions have impacted our aquatic resources over the past century. “
To complete the picture that Dr. Fritts hopes to paint for the scientific community, her group plans to analyze samples that have been collected very recently throughout the entire length of the Illinois, in the hope that they will be able to identify effective remediation and reclamation efforts that have been undertaken. The secondary result of this research could, if successful, also present a tangible record of contaminant movement throughout the river system.
This groundbreaking research is vital in many ways. In Dr. Fritts’ words, “As we move into the future, it will become increasingly important to have a holistic picture of how our aquatic systems have changed over time.” I believe that this will persist as a vital truth as society moves forward in every aspect of study. Dr. Fritts’ work serves as encouragement and inspiration for those who choose to undertake such an inclusive and system-based role of thought.
[1] http://www.dgif.virginia.gov/wildlife/freshwater-mussels.asp
[2] http://www.albaecology.co.uk/mollusc-of-the-glen.html