Editorial

Abstract

Since 2014, the Brazilian press has been reporting several problems related to the water. For the same period, the state of São Paulo, especially its metropolitan region, has undergone a serious water shortage for its urban supply. This shortage occurs not only owing to rainfall far below the historical average for the region, but also to management failures, lack of better planning, excessive waste of treated water, very poor sewage treatment, etc. On the other hand, the excessive rainfall in other regions such as the Amazon and the southeast of Bahia state has caused floods and landslides with large economic losses and deaths. These disturbances caused by excessive rainfall could also have been reduced through preventive actions, better planning, and more accurate weather forecasts. Undoubtedly, these water excess and shortage problems must be reduced, and greater investments are required to avoid the damages they cause. It is worth noting that shortage and excess of water do not occur only in Brazil, but in several other countries, for instance, the current water shortage in western and southern states of the USA. Nevertheless, we should not forget the many other problems that have negatively impacted aquatic ecosystems in Brazil and in the world, which also involve harm to humans. Pollution, contamination and loss of biodiversity have been described in several scientific studies; and there are solutions to these problems. 'Acta Limnologica Brasiliensia' Journal has contributed to the advancement of knowledge on aquatic ecosystems, publishing articles that often address the impacts and possible solutions for these problems. Number 2, Volume 27 of 'Acta' comprises ten articles that contribute to the knowledge of different problems affecting aquatic environments and show possible solutions. The first article of this Issue provides an overview of studies on