How to mitigate cyanobacterial blooms and cyanotoxin production in eutrophic water reservoirs?

Abstract

Cyanobacterial blooms and cyanotoxin production were studied for 2 years in four hydrologically modified lakes with nutrient-rich waters. We hypothesized that frequency of flushing may considerably influence cyanobacterial blooms. Abundance, biomass and diversity of cyanobacteria as well as cyanotoxins' variability and concentrations (by HPLC-PDA; -FLD) were determined. In two larger lakes, into which nutrient-rich water was supplied once a year, lower cyanobacterial species diversity, higher biomass of Microcystis spp., Aphanizomenon spp., Dolichospermum spp. and higher microcystin (MC) concentrations were found. In the other lakes, with several irregular water-level manipulations per year (alternating outputs and inputs), higher diversity, lower biomass of cyanobacteria and MC concentrations were observed. MC-LF, -LR and -RR produced by Microcystis spp. predominated in the more stable lakes, whereas in the lakes with frequent water manipulations different species of Oscillatoriales developed and MC-LA, -LY, -LW and -WR were also important. RDA analysis revealed that the frequency of water manipulations was the most significant variable for composition of cyanobacterial communities. The study highlights that a higher frequency of water-level manipulations, which increased flushing rate, was beneficial to nutrient-rich water reservoirs.

Impact of lake‐catchment processes on phytoplankton community structure in temperate shallow lakes

“…These phytoplankton groups also have the ability to respond quickly to the availability of environmental resources because of potentially high growth rates. Pawlik-Skowronska and Toporowska (2016) showed that intensive and frequent flushing increased cyanobacteria species richness and biodiversity and lowered the biomass of Microcystis and Aphanizomenon in two hydrologically modified lakes despite their periodical supply with nutrient-rich river waters. ++++: dominant taxa (contribution >50% in the total phytoplankton abundance); +++: subdominant taxa (25-49%); ++: accompanying taxa (10-24%); +: 5-9%; s: spring, sr: summer; a: autumn.…”

“…Over the last few decades, some studies have shown that water level fluctuations (WLFs), water flushing time (Tf), and flow rate may explicitly or implicitly influence the abundance and composition of phytoplankton (Bailey-Watts, Kirika, May, & Jones, 1990; Leira & Cantonati, 2008, and references therein), including the cyanobacteria community (Carvalho et al, 2011;Padisák, Köhler, & Hoeg, 1999;Pawlik-Skowronska & Toporowska, 2016;Romo, Soria, Fernández, Ouahid, & Barón-Solá, 2013). A few reports (Leira & Cantonati, 2008, and references therein) have revealed that WLFs affect phytoplankton abundance, biomass, size structure, taxonomic composition, species diversity, and rate of community compositional change.…”

The role of abiotic and biotic environmental factors in shaping epiphyton on common reed in shallow, hydrologically transformed, temperate lakes

“…Lakes differ in water management. In Lakes Skomielno and Krzczeń, water loss occurs naturally by evaporation and the lakes are refilled twice a year (in spring and autumn) with water from the above mentioned canal (Suchora, 2012;Pawlik-Skowrońska and Toporowska, 2016). This process is controlled by the Regional Management Office for Irrigation and Water Systems in Lublin.…”

“…and the frequency of WLFs in Lakes Krzczeń, Tomaszne, and Skomielno were obtained from calculations based on watermark readings presented by Suchora (2012) and Pawlik-Skowrońska and Toporowska (2016) and were highest in Lakes Tomaszne and Krzczeń (Tab. 1).…”

“…Man-made WLFs were the most frequent in Lake Tomaszne (1-2 per season), whereas in Lakes Skomielno and Krzczeń, they occurred once a season (Tab. 1): in spring and autumn (Suchora, 2012;Pawlik-Skowrońska and Toporowska, 2016).…”