Limnology is the study of inland aquatic ecosystems. Pronounced, the name comes from Ancient Greek λίμνη (límnē) 'lake' and -λογία (-logía) 'study of'. It includes aspects of the biological, chemical, physical, and geological characteristics of fresh and saline, natural and man-made bodies of water. This includes the study of lakes, reservoirs, ponds, rivers, springs, streams, wetlands, and groundwater. Water systems are often categorized as either running (lotic) or standing (lentic).