In 2008, PIM Publishing House issued the second edition of Water Ecology by Mircea Nicoarã and Dorel Ureche.
The elaboration of this work and the necessity of re-evaluating it is based on the existence of some major international problems related to the water environment and to their becoming critical within the last decades.
The most important problems of this environment which determined the intensification of their studies and researches are: the necessity of maintaining water quality and quantity, the reduction of biological diversity, the impact of climate change (especially temperature and UV-B radiations) on water ecosystems and human health.
The concept of „ecological homeostasis” referring to population (Botnariuc 1967) is more topical than ever, in the context of significant changes in the water environment and can be extended to biocenosis, too. | 
