"The Jubilee Phenomenon" is a lesson plan that provides a sequence of learning exercises to help students understand what is locally known as a "Mobile Bay jubilee"(Alabama) and the importances of preserving estuaries. The lesson plan is divided into three exercises. In "Exercise 1: What is the Jubilee Phenomenon", students learn the specific conditions that must be present for a jubilee event to occur by engaging in three activities. The first activity is a reading jigsaw for the article, "Deadly Oxygen Levels in Mobile Bay", followed by a map activity and a short animation activity. Students questions are provided to guide development of their understanding. The second exercise, "Exercise 2: Layered Water in the Estuary", engages students in a lab activity that demonstrates how water stratifies due to differences in salinity. Student questions are provided to facilitate development of the concept. In the third and final exercise, "Exercise 3: When did a Jubilee Occur?", students use graphs of tide data, wind direction, and dissolved oxygen to determine which day(s) a jubilee occurred. A set of student questions is provided to guide students through the exploration and understanding of the concepts. For your reference, the definition of "jubilee" according to Webster's II New College Dictionary (2001) is "a special annniversary, especially a 50th anniversary".