Oceanography is a scientific study that investigates the physical and chemical properties of the world's oceans and seas, as well as their origins and geologic framework and the species that reside in them. Physical oceanography, chemical oceanography, marine geology, and marine ecology have traditionally been classified into four distinct but related branches of oceanography. The term "oceanography" refers to the combination of these several branches. Oceanography is also critical for determining the impact of pollutants on ocean waters and maintaining the quality of the oceans waters in the face of increasing human demands.
Limnology is the study of inland freshwaters, including both static bodies like lakes and running waters like rivers. It includes topics such as biology, geology, physics, chemistry, and climatology, as well as wetland protection and ecosystem services. The provision of guidelines for water management and pollution prevention is one of the most important tasks of limnology. Limnologists also look into how to conserve both the species that lives in lakes and rivers and the lakes and rivers themselves.