estrogen: a general term for female steroid sex hormones that are secreted by the ovary and responsible for typical female sexual characteristics
steroid hormone: any hormone affecting the development and growth of sex organs
eutrophication: excessive nutrients in a lake or other body of water, usually caused by runoff of nutrients (animal waste, fertilizers, sewage) from the land, which causes a dense growth of plant life; the decomposition of the plants depletes the supply of oxygen, leading to the death of animal life