Conservation is the preservation or efficient use of resources (in an efficient or ethical manner), or the conservation of various quantities under physical laws.
Shallow lakes have been greatly affected by increased concentrations of nitrogen and phosphorus from intensive agriculture and increased human populations. These key nutrients for plant growth enter the aquatic environment, changing clear water to turbid through a phenomenon called eutrophication.
EN 
CS
DE
ES
FR
HU
IT
PL
PT
РУ
SK
TR
УК
AR
中文
