Parameter Tree:
EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > WATER QUALITY/WATER CHEMISTRY > NUTRIENTS

Definition:
Elements essential for growth and survival of a given organism. Directly or indirectly, nutrients have roles in metabolism that no other nutrients fulfills.

Reference:
Starr, C. and R.Taggart. 1998. Biology: the unity and diversity of life. Wadsworth Publishing Company. Belmont, California.