Grad Research Experience: Abby Matheny

Abby Matheny, an environmental graduate student advised by William Arnold.

"I chose to continue my studies at the University of Minnesota because its College of Science and Engineering is ranked among the top engineering schools in the nation and I have access to internationally renowned research centers such as the St. Anthony Falls Laboratory. With Dr. Bill Arnold as my advisor, I am conducting research among the best scientists in the field of environmental engineering."

I grew up in Pittsburgh, Pennsylvania, where if we are known for one thing other than our sports team (go Steelers!), it is pollution. With a history of coal mining and steel production, Pittsburgh used to be nicknamed “the smoky city.” As I began to understand Pittsburgh’s long history of pollution, I developed a strong interest in its consequences and a desire to mitigate such contamination for the health of both the human and natural worlds.

Cyanobacteria, ubiquitous in all aquatic environments, have been on earth for billions of years. They are an important source of dissolved organic matter (DOM) in natural water systems. DOM is the main absorber of sunlight in aquatic ecosystems and a key reactive intermediate in the photodegradation of many other compounds, including toxins and pollutants. In particular conditions, cyanobacteria can experience considerable growth and give rise to harmful algal blooms. 

These blooms are expected to increase with climate change, leading to changes in the composition of DOM in natural waters.

Few studies have investigated how a future increase in these cyanobacterial algal blooms will change DOM composition and subsequent production of photochemically produced reactive intermediates (PPRI) in natural water systems, perhaps also changing the way that pollutants or toxins degrade in water. We also do not fully understand how different wavelengths of light influence this process. Due to stratospheric ozone recovery and the emission of more greenhouse gasses and other particles into the atmosphere, many bodies of water will experience a future shift in sunlight spectral irradiance; yet we do not know how these climate-induced trends will affect the surface-water photochemistry of Minnesota’s waters. The main objectives of my research project build on all of this. They are to grow cyanobacterial cultures and characterize the DOM produced and to measure the wave-length dependent PPRI production from the produced DOM and compare that to a standard DOM.

If we can quantitatively express future trends in surface-water photochemistry, we can increase the accuracy of our models and facilitate robust decision making in the face of a rapidly changing climate. My research outcomes will provide evidence that supports emerging environmental regulations and remediation strategies for the treatment of water contaminated with cyanobacteria and the harmful cyanotoxins they produce. Understanding how harmful algal blooms affect our natural waters is important for the protection of all water users.