Page 5 - CEGE Magazine Fall 2024

I grew up in Pittsburgh, PA, 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.
  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. 
A glimpse of graduate student research experiences in CEGE
University of Minnesota College of Science and Engineering | DEPARTMENT OF CIVIL, ENVIRONMENTAL, AND GEO- ENGINEERING 5
In the Midwestern metropolis of Minneapolis-St. Paul,
the University of Minnesota’s CEGE Graduate
Programs offer research opportunities with some
of the finest faculty and facilities. These stories describe
what that means for six graduate students doing
research in CEGE.
Abby Matheny, Environmental
Advised by William Arnold