Growing with Aquaponics at UConn
Elaina
Hancock - UConn Communications
UConn’s
Spring Valley Student Farm is now home to a newly up-and-running aquaponics
facility, a welcome addition to the farm, which already grows and provides
fresh produce to campus.
The year-round means of
growing vegetables is a source of pride for graduating senior Kelly Pfeiffer
’18 (CLAS), a psychological sciences major who has helped shape an idea into
reality.
Starting out as a hope, then
transitioning into a grant proposal, the aquaculture plan for Spring Valley
Student Farm is now finally coming to fruition, through the tenacity of the
students who work at the farm.
Former undergraduates Carl
Underwood ’16 (CAHNR, CLAS) and Gabriel DeRosa ’17 (CAHNR) originally hatched
the concept and were awarded an IDEA Grant to get it
started. When they graduated, Pfeiffer took on the project and has carried it
to completion as the current aquaponics plant care specialist.
“My goal was to have the
aquaponics system up and running with fish by the time I graduated, and this is
now happening, all in time for the summer growing season,” says Pfeiffer, one
of 11 students who live on the farm.
“We each have our niche
project,” she adds. “The aquaponics system has been mine.”
How the system works
Hydroponics is the
cultivation of plants in water, however aquaponics combines the rearing of
aquatic animals in a hydroponic environment. Nitrogen is a nutrient plants rely
on for growth and nitrogenous wastes are a fact of life for any organisms, such
as fish, that metabolize proteins. The resulting waste is excreted as
nitrogen-based compounds, such as ammonia or urea.
In an aquaculture system,
there must be a way to manage and remove excess nutrients from the aquatic
environment, otherwise the water becomes toxic to the fish.
These wastes,
highly rich in nitrogen, are broken down by a community of bacteria, into forms
of nitrogen that are easily used by plants. No longer simply a nuisance, the
fish waste is now fertilizer.
Pfeiffer explains that
aquaponics systems and traditional agriculture are similar, in that they both
rely on monitoring of macro and micro nutrients to effectively grow healthy
plants. So why grow in an aquaponics system?
“There’s a surprising
statistic for this technology, that you can grow four heads of lettuce in an
aquaponics setting for every one grown through traditional soil growing
methods,” says Pfeiffer.
In other words, grow more in
less space, using the closed loop and symbioses between plants, animals, and
bacteria.
Koi fish will soon be added to the 450-gallon tank of the
aquaponics set-up to supply the nitrogenous wastes, creating a symbiosis or
closed loop between the animals, bacteria, and the plants, all reliant on one
another.
Pfeiffer says striking the
right balance can make aquaculture tricky, and will depend on trial and error
as well as close, continuous monitoring of nutrient levels in the water.
The system flows from the
fish tank, where water and solid fish waste are siphoned off into a filter, and
then a large tray filled with porous shale that further filters the water and
also creates a medium where the bacteria live.
The expanded shale bed is a
two-way filter, filtering as the water levels rise and fall, as well as where
the bacteria colonize.
It is also an area of the
system where plants can be grown. Although not intentionally planted, a lone
squash plant has volunteered and is demonstrating how fertile the planting area
is.
“Somehow a seed got into the
shale and we left it to see how it did,” says Pfeiffer, “and it’s doing great.”
Basil has since been planted
in the bed, along with the squash plant.
From the shale bed, the
filtered water then drains into deep-water culture beds, each around 12 inches
deep. The beds are currently home to the system’s first crop – romaine lettuce.
Through circles cut into blue sheets of Styrofoam insulation board, the lush
lettuce plants emerge, their roots reaching into nutrient-rich water below.
Planting out a crop is a
matter of starting the seeds in soil and then transplanting into floating
plugs.
Since lettuces take only a couple of months to go from seed to harvest,
the system will be capable of providing a fair amount of produce throughout the
year, Pfeiffer says. The produce will be supplied to Dining Services.
Growing Collaborations
Besides growing food, the
system is also sprouting research projects. Julia Cartabiano, manager of the
Spring Valley Student Farm, says there are several collaborations stemming from
the aquaponics system in various disciplines across campus, including two
professors in the School of Business who plan to use the greenhouses on the
farm as a learning lab, and a computer science student in the School of
Engineering who hopes to work with the farm as his senior design project.
Undergraduate researcher
Tanzin Begam ’19 (CLAS), a third-year biology student with a minor in
bioinformatics, recently presented a poster on her work studying the microbial
community of the aquaponics system. As in any ecosystem, the right mix of
bacterial species is vital for the health and success of an aquaponics system.
More specifically, Begam
says she was looking at the succession of the bacterial community within the
system after set-up and before plants or fish were introduced.
It has been a great learning
experience, she says. “In the fall semester, I was working out the best DNA
extraction methods, and this semester I was analyzing the data. I have been
learning so much.”
Her advisor, facility
scientist Kendra Maas, says they weren’t able to find published research
looking into how microbial communities are established within an aquaponics
system, so this research may be a first.
They hope to continue their analysis
when the Koi are introduced. Maas hopes to one day make these tests an open
service to the expanding aquaponics agricultural community across the state.
“As aquaponics becomes more
and more common in Connecticut, this could be a useful service for growers,”
she says.
The Spring Valley Farm
aquaponics system is another great example of how UConn’s agricultural roots
are helping to grow research innovations in unexpected ways.
After graduation, Kelly Pfeiffer will
start work as a marine science instructor at the Catalina Island Marine
Institute in California. Tanzin Begam hopes to graduate in May 2019, and will
continue her study of the aquaponics system’s bacterial community in the
meantime.
