Aquatic biology as a discipline is as diverse as aquatic systems themselves.
This discipline includes the study of lakes, rivers, streams, wetlands and organisms such as bacteria, protozoa, invertebrates, insects, fish, aquatic plants and more. Aquatic biology also includes the study of the abiotic such as nutrients, light and pollution, and how these in turn affect the system in question. By choosing a more general Aquatic Systems emphasis, you can tailor your program to best suit your interests.
With an emphasis in Aquatic Systems, your classes (beyond the requirements) can range from aquatic plants to fisheries management to freshwater invertebrates to wetland ecology. This diverse emphasis will help you become a well-rounded aquatic ecologist knowledgeable in a variety of disciplines.