Occurrence of toxic blooms of Microcystis aeruginosa in a central Chilean (36° Lat. S) urban lake

Viviana Almanza,Oscar Parra,Carlos E De M Bicudo,Roberto Urrutia,Ricardo Figueroa,Carolina Baeza,Johana Beltran

doi:10.1186/s40693-016-0057-7

Abstract

During the last decades the frequency and global distribution of toxic cyanobacteria blooms has increased globally, which has been attributed to the eutrophication and climate change. In Chile there have been reports on blooms in aquatic ecosystem in localities with high density population and on the presence of five congeners of microcystins but only two documented toxics blooms with hundreds fish kills. We investigated the presence of toxic cyanobacteria blooms in the Lo Galindo urban lake, Concepcion city, and the environmental factors that influence the abundance of cyanobacteria and microcystins concentration. Lo Galindo Lake, is used for various recreational and eventually as a drinking water source. Toxic blooms of Microcystis aeruginosa are developed in Lo Galindo lake, those that occur throughout the year in a wide range of environmental conditions, forming scums blooms during summer and dispersive blooms in all seasons. There are different microcystin congeners, the most frequent congener was MC-RR (21 %) and the highest concentration corresponded to 115.4 µg L-1 MC-LR. The dominance and development of the M. aeruginosa blooms in the lake is determined by various environmental factors such as temperature, nutrients, diversity of taxa and wind speed that affect the formation of disperse-type blooms and/or scums; the latter are developed only in summer, coinciding with the highest temperature and concentrations of total microcystins. In the lake the microcystin and different types of congener is highly variable, so special care is recommended to use lake water for consumption and for recreational activities. The emergence and persistence of Microcystis blooms in this body of water are considered a potential health risk for the inhabitants of the area, considering the proximity and the system use by the inhabitants.

Highlights

During the last decades the frequency and global distribution of toxic cyanobacteria blooms has increased globally, which has been attributed to the eutrophication and climate change
The objective of this study was to investigate the presence of toxic cyanobacteria blooms in the Lo Galindo urban lake, Concepción city, and the environmental factors that influence the abundance of cyanobacteria and microcystins concentration
Microcystis aeruginosa abundance A total of 30 samples were taken between December 2012 and March 2014 in the Lo Galindo Lake (Fig. 1)

Summary

Introduction

During the last decades the frequency and global distribution of toxic cyanobacteria blooms has increased globally, which has been attributed to the eutrophication and climate change. Frequency and global distribution of toxic cyanobacteria blooms have increased worldwide, due to eutrophication and climate change (increased temperature, alteration of rainfall patterns and water bodies residence time) [1]. (Chlorococcales, Cyanobacteria) are the most common in freshwater bodies around the world and of great concern due to the production of hepatotoxins [3] This cosmopolitan cyanobacteria form macroscopic colonies composed of thousands of cells, which can regulate their position in the water column by the presence of many intracellular aerotopes [4]. This dense layer is known as scums and/or hyperscum, whereas when the colonies are dispersed in the water forming green patches they are known as dispersive colonies or blooms [5, 6]

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