As winter continues its grip on Minnesota, a tropical river ecosystem is thriving inside the OWS greenhouse. We started last spring with a small-scale experiment, asking how efficiently we could turn food waste into worms, worms into tilapia, and tilapia waste into basil.
Last summer we started up a 600-gallon aquaponics system where we grew a crop of tomatoes, and now we’re growing kale and basil. I also started a collaboration with Healing Haiti, an aid organization that runs a commercial-scale aquaponics system in a village near Port-au-Prince.
Students in my Urban Ecosystem Ecology class are currently constructing an ecosystem model using STELLA software, based on our data from the small experiments, the larger greenhouse system, and the giant system in Haiti. Our goal is to create a management tool that will help managers run the Haiti system more efficiently, thereby increasing the capacity for food production in the poorest country in our hemisphere.
We’re also kicking off a new experiment with the six smaller aquaponics systems, involving freshwater shrimp (Macrobrachium rosenbergii). We’ll be growing shrimp and tilapia, separately and in combination, to measure overvielding–i.e., do we get extra animal production per unit of food added in the higher biodiversity treatments?
The shrimp have arrived and are settling in to their new homes. Unfortunately, with the cold weather, our new tilapia have not been shipped from their home in south Florida. Hopefully they’ll ship in a few weeks and we’ll get started. Stay tuned for details.