Morphological, ecological and toxicological aspects of Raphidiopsis raciborskii (Cyanobacteria) in a eutrophic urban subtropical lake in southern Brazil

Abstract

A dense perennial bloom of Raphidiopsis raciborskii was observed in an urban lake (29°53'13"S and 51°09'29.9"W). Due to supposed toxicity, this study analyzed the morphology of the species, evaluated the main factors that influence its growth, and examined bloom toxicity. Two sites were sampled monthly from November 2009 to November 2010. The species was found in all samples and dominated in 77% of the samples. Highest density was recorded at the end of summer (March-199,550 ind.mL-1) at 26.6 ºC and pH 7.8. High densities were also found at low temperatures (72,145 ind.mL-1 at 12.6 °C and 130,475 ind.mL-1 at 14.5 °C) and at minimum (5.4) and maximum (8.7) pH, reaching 89,964 ind.mL-1 and 61,400 ind.mL-1 , respectively. Nitrogen availability was high, especially ammonium [(60-)140-660 μg.L-1 ], and phosphorus was low (orthophosphate < 10 μg.L-1). These results support that R. raciborskii has a wide tolerance to abiotic variations. Saxitoxins and gonyautoxins were found in the bloom.

Cyanobacterium Raphidiopsis raciborskii and its toxin in Buon Phong reservoir, Dak Lak province, Vietnam

“…Abiotic variables affecting the biovolume of R. raciborskii in this study were dissolved nitrogen and phosphorus (N-NH 4 , P-PO 4 ). The positive correlation between R. raciborskii and N-NH 4 and P-PO 4 in our study was also observed in previous studies (Kokocinski et al, 2012;Nguyen et al, 2017;Burford et al, 2016Burford et al, , 2018Werner et al, 2020). These studies suggested that N-NH 4 and P-PO 4 were considered as the preferred source of N, and P to stimulate the growth of the R. raciborskii populations.…”

“…These studies suggested that N-NH 4 and P-PO 4 were considered as the preferred source of N, and P to stimulate the growth of the R. raciborskii populations. The biomass of this species is higher in lakes with high N-NH 4, and P-PO 4 concentrations (Kokocinski et al, 2012;Nguyen et al, 2017;Burford et al, 2016Burford et al, , 2018Werner et al, 2020). On the contrary, a number of studies noted that R. raciborskii can still prevail even under the low N and P conditions (Burford et al, 2018Recknagel et al, 2019Galvanese et al, 2019;Xiao et al, 2020;Werner et al, 2020;Li et al, 2020).…”

“…The biomass of this species is higher in lakes with high N-NH 4, and P-PO 4 concentrations (Kokocinski et al, 2012;Nguyen et al, 2017;Burford et al, 2016Burford et al, , 2018Werner et al, 2020). On the contrary, a number of studies noted that R. raciborskii can still prevail even under the low N and P conditions (Burford et al, 2018Recknagel et al, 2019Galvanese et al, 2019;Xiao et al, 2020;Werner et al, 2020;Li et al, 2020). This is partly explained by the high storage and the absorption capacity for N-NH 4, and P-PO 4 of R. raciborskii (Burford et al, 2006;Kenesi et al, 2009;Kokoscinski et al, 2012).…”

“…Raphidiopsis raciborskii (previously Cylindrospermopsis raciborskii) is a freshwater, planktonic filamentous and potentially invasive cyanobacterium that has been known worldwide for forming cyanobacterial harmful algal blooms (cyanoHABs) (Werner et al, 2020).…”

Population Dynamics of <i>Raphidiopsis raciborskii</i> and Cylindrospermopsin Concentration in Ea Nhai Reservoir in Dak Lak Province, Vietnam

“…Cyanobacterial harmful algal blooms (CyanoHABs) are particularly problematic due to their ability to reduce water quality, disrupt nutrient cycling and produce toxic secondary metabolites (cyanotoxins) that are released into the aquatic environment [4,5]. Raphidiopsis raciborskii (formerly known as Cylindrospermopsis raciborskii) is a harmful, planktonic cyanobacterium.…”