Aquatic systems in semi-arid Brazil: limnology and management

Abstract

Aquatic systems in semi-arid Brazil include natural shallow lakes, artificial reservoirs and intermittent streams and rivers. These systems are distinctive features in the semi-arid landscape and comprise a range of associated systems functioning as an ever-changing mosaic of dry/wet patches. Lakes and reservoirs in semi-arid Brazil are subject to important periods of water shortages, whereas rivers and streams are characterized as highly variable and driven by the extremes of water flow and its absence. Within this view a catchment-scale approach must be used to create a holistic model to conceptualize and comprehend these aquatic systems, since the aquatic environment types in the semi-arid region of Brazil incorporate broader aspects within the catchment scale such as geomorphology, vegetation, climate and land use. This paper summarizes some of the information on the aquatic systems of the Brazilian semi-arid region and shows the importance of limnological studies in this region. It also attempts to establish perspectives for future research considering the catchment as a scale for surveying biological processes and limnological characteristics of the various aquatic systems. It is presented information on their overall structure and functioning, as well as characteristics of some biological communities, such as phytoplankton, periphyton, aquatic macrophytes, benthic invertebrates and fish. The importance of the understanding of eutrophication in reservoirs and the role of the dry phase in streams is emphasized, and information on possible actions of planning and management to improve water quality of reservoirs are presented.

Phosphorus dynamics in the water of tropical semiarid reservoirs in a prolonged drought period

“…The main input of this nutrient into aquatic environments of the semiarid region is diffuse pollution, reaching the water body through rainfall. In periods of no rain, there are no external inputs of nutrients (Naselli-Flores, 2003;Barbosa et al, 2012), so the increase in phosphorus in the water is mainly due to the amount of autochthonous nutrient that has been concentrated because of the decrease in water volume (Volohonsky et al, 1992).…”

“…However, many reservoirs suffer negative impacts in water quality caused by human activities and the natural conditions of the region (Barbosa et al, 2012). The non-point sources…”

Avaliação Da Qualidade De Um Afluente Utilizado Para Irrigação Na Região Semiárida De Pernambuco (Nordeste Do Brasil)

“…Nestas áreas, portanto, corpos d'água são frequentemente utilizados para fins múltiplos, incluindo irrigação de pastagens e dessedentação de animais (BARBOSA et al, 2012).…”

Potential ecological distribution of alien mollusk Corbicula largillierti and its relationship with human disturbance in a semi-arid reservoir

“…Some species are highly tolerant to physical and chemical variations, and colonize new habitats in reservoirs as they present high reproduction rates and adapt easily to different types of environment (Ruse 2010). In this semi-arid region, aquatic ecosystems present particular dynamics because of the following features: (1) distinct climatic and geomorphological characteristics; (2) highly variable precipitation both in time and in space; (3) low temperature variation (temperatures above 25°C); (4) high potential evapotranspiration, which promotes hydric deficit for about nine months per year; (5) shallow soil; (6) hydrographic basins with intermittent flow; and (7) deciduous vegetation coverage at the Caatinga biome (Barbosa et al 2012).…”