Estuaries are home to an wide variety of organisms and represent delicate ecosystems. The Elkhorn Slough is the site of numerous human activities, including agriculture, recreation, transportation, fishing and energy production. With so many user groups struggling to coexist in the slough with as little disruption of the natural environment as possible, several essential questions arise. Do these activities add additional nutrients to the slough? Are they changing the delicate balance of life in the slough? Is nutrient loading a problem in this watershed? Where do the nutrients that arrive in this watershed originate from? What can be done to alleviate problems that may occur? This online case study will help students examine these questions.