In this activity, learners create a sealed, mini ecosystem that supplies freshwater shrimp with food, oxygen, and waste processing for at least three months. Learners will collect water, amphipods, and sludge containing microscopic copepods and ostracods from a local pond. Learners will add the pond samples to a jar of nitrate-poor fresh water and aquatic plants and animals. They can observe their mini biosphere in action over the succeeding months.