Francesca Holland
Horseshoe Crab Habitat Design
Maritime Aquarium: Life Support Systems and Educational Exhibit Design
​Project Duration: 6 Months, Commitment: Part-Time, Years: 2018-2019
The Cause
Horseshoe crab populations are globally threatened by human exploitation and are considered endangered in New England. These ancient creatures, around for over 400 million years, play a vital role in ecosystems—especially for red knot birds and even humans. Their unique sky-blue blood clots in response to bacterial toxins, making it essential for sterilizing vaccines, drugs, and medical devices.
The Maritime Aquarium in Norwalk, CT is passionate about leading conservation efforts for the local horseshoe crab population. In 2018 the aquarium received a donation from Richard and Kim Alexander as well as the Ballard Foundation to update and expand their dated horseshoe crab exhibit. At the time, the Main Tank’s chiller was not able to maintain the optimal temperature for the adult horseshoe crabs inside.
My Role
I was adamant about helping the Maritime Aquarium for my University of Connecticut (UConn) engineering senior design project with fellow classmates Kaihla Tomassi, Ewelina Bucior and Caylin Cyr, plus our faculty advisor Dr. Kristina Wagstrom (the only all-female senior design team in UConn's 2019 Chemical Engineering class). We helped re-design the aquatic life support system for the adult main tank and validated the design of two new rack systems for hosting horseshoe crab babies at various life stages—from eggs to adolescence until ocean release. One rack system was for visitor display, while the second "Grow-Out Tank" was built partially by our team and installed behind the scenes to reduce overcrowding as adolescent crabs grow. I also designed educational visuals for the client-facing exhibit. A big thank you to the Maritime Aquarium staff, especially Associate Director of Life Support Erik Holmberg, for teaching us so much and providing real hands-on experience.
The Process
First, I researched why the current life support system was inadequate and identified more effective heat exchanger replacements for the chiller. The team then modeled both the Main Tank and Rack Systems in Aspen Plus and performed heat transfer calculations to validate that the chosen AquaLogic heat exchanger would maintain proper temperatures. We used fluid mechanics equations to validate pump sizing. I evaluated the Main Tank's mechanical filter function, and we analyzed filtration sump effectiveness in the Rack and Grow-Out Systems to ensure ammonia levels stayed below thresholds required for baby horseshoe crab health.
For the Grow-Out Tank, we learned from other breeding systems at the aquarium to plan out the system’s process flow and order PVC parts. As a team, we regularly traveled across the state to visit the aquarium and build the Grow-Out Tank by hand. We screwed the stand together, installed the tanks, sump and pump, hand cut and glued all the piping and valves together, etc. The team also modeled the Grow-Out Tank system in Aspen Plus to validate the pump and so I could make recommendations about temperature regulation which were later implemented by the aquarium via the installation of a chiller.
I also created some digital drawings about horseshoe crabs using Adobe software for the aquarium and one of them is now a formal part of the updated educational display at the exhibit:
All system design updates have been made and conservation efforts are in full swing. Some adolescent horseshoe crabs have already been released to the Long Island Sound!
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