This book guides students through use of a single inexpensive and intuitive experimental microcosm system to teach ecological concepts, the scientific method, experimental design, and freshwater ecology. At its heart are eight carefully-designed and fully tested laboratory experiments that teach foundational ecological concepts and serve as an encouraging framework for testing novel questions in ecology. Designed as a companion to the Lake-in-a-Tube microcosm system, this book features activities for college-level students that are adaptable to various levels of lab capacity, from none to fully-equipped biology laboratories. Additional content supports development of novel experimental questions for inquiry-based independent projects and Course-based Undergraduate Research Experiences. Activities are centered around the global problem of freshwater harmful algae blooms in lakes and the consider the various abiotic and biotic factors that affect them.