Cyanobacterial blooms in freshwaters bodies in a semiarid region, northeastern Brazil: A review

Abstract

Harmful cyanobacterial blooms have caused several problems in freshwater environments due to their prolific growth and the harmful cyanotoxins produced by some species. The occurrence of these organisms has increased in recent decades due to climate change and eutrophication, although most studies are from temperate regions in the Northern hemisphere. This review presents data about cyanobacteria occurrence, dominance, and toxicity events in freshwater bodies in a semiarid region of Northeast Brazil, in the tropical Southern hemisphere. We performed a literature survey of cyanobacteria publications from 1930 to 2016. We made a list of all the dominant species registered in each state, noted their distribution and occurrence of dominance events involving one or more species, and the registered records of toxic blooms, including information about the toxins involved and the range of values. We selected 102 publications that described cyanobacteria Accepted Article www.jlimnol.it occurrence from states in Northeast Brazil; these publications included relevant contributions regarding cyanobacteria distribution, richness, density, and biomass. Forty-nine dominant species were recorded, with the most representation found in the state of Pernambuco (30 spp.). The genera with the highest occurrences were Microcystis, Cylindrospermopsis, Planktothrix, Dolichospermum (=Anabaena), and Geitlerinema, especially the species Cylindrospermopsis raciborskii, Microcystis aeruginosa, and Planktothrix agardhii. Episodes of toxic blooms were observed in four states. Microcystins, cylindrospermopsin, saxitoxins, and anatoxin-a(S) were found to be associated with these blooms. In Northeast Brazil, harmful cyanobacterial blooms are common in urban and public reservoirs. However, in recent years, cyanobacterial blooms in this region have been more intense and perennial, with high biomass occurring throughout the year.

Influence of water volume reduction on the phytoplankton dynamics in a semi-arid man-made lake: A comparison of two morphofunctional approaches

“…Although studies on phytoplankton functional classification in Brazilian semi-arid lakes are scarce, the occurrence of groups S N and VIII represented by Cylindrospermopsis raciborskii is frequently related to this region, particularly during drought periods and warmer conditions (Bouvy et al 1999, 2000, Soares et al 2013, Moura et al 2018). This study also corroborates the predictions regarding climate change scenarios; that is, in shallow lakes during extended droughts, the dominance of bloomforming cyanobacteria will tend to become more frequent in the future (Intergovernmental Panel on Climate Change [IPCC] 2007, Marengo et al 2010, Moss et al 2011.…”

Drivers and ecological consequences of dominance in periurban phytoplankton communities using networks approaches

“…Continental aquatic ecosystems are considered among the most vulnerable to the combined pressure of anthropogenic activities and climate change (Adrian et al, 2009). In the recent decades, these pressures have led to an increase in the frequency and intensity of phytoplankton blooms in lakes all around the world (Aguilera et al, 2017b;Almanza et al, 2018;Beaver et al, 2018;Dokulil and Teubner, 2000;Moura et al, 2018;Ndlela et al, 2016;Paerl and Huisman, 2008;Paerl and Otten, 2016). Phytoplankton blooms correspond to rapid increases of primary producer's biomass, often associated with the dominance of only a handful of taxa.…”

Impacts of drying and reflooding on water quality of a tropical semi-arid reservoir during an extended drought event

“…The factor that stands out in water quality improvement after reflooding in Dourado is the reduction of phytoplankton biomass: the trophic state changed from eutrophic to mesotrophic. This aspect is of great importance because of the lower risk of potentially toxic cyanobacteria blooms whose presence in Brazilian semi-arid reservoirs has already been reported (Panosso et al, 2007;Costa et al, 2009;Moura et al, 2018). Despite this trophic state change, the internal loading of phosphorus from sediment (autochthonous source) can returned the high nutrients concentration.…”