limnology
Scientific study of inland waters such as lakes, ponds, and marshes. A technical academic term.
He is majoring in limnology at university.
Water quality surveys are essential for limnological research.
Compound of 湖沼 (こしょう, 'lakes and marshes') + 学 (がく, 'study'). The term is a direct calque from English 'limnology'.