Combatting cyanobacteria with hydrogen peroxide: a laboratory study on the consequences for phytoplankton community and diversity

Abstract

Experiments with different phytoplankton densities in lake samples showed that a high biomass increases the rate of hydrogen peroxide (HP) degradation and decreases the effectiveness of HP in the selective suppression of dominant cyanobacteria. However, selective application of HP requires usage of low doses only, accordingly this defines the limits for use in lake mitigation. To acquire insight into the impact of HP on other phytoplankton species, we have followed the succession of three phytoplankton groups in lake samples that were treated with different concentrations of HP using a taxa-specific fluorescence emission test. This fast assay reports relatively well on coarse changes in the phytoplankton community; the measured data and the counts from microscopical analysis of the phytoplankton matched quite well. The test was used to pursue HP application in a Planktothrix agardhii-dominated lake sample and displayed a promising shift in the phytoplankton community in only a few weeks. From a low-diversity community, a change to a status with a significantly higher diversity and increased abundance of eukaryotic phytoplankton species was established. Experiments in which treated samples were re-inoculated with original P. agardhii-rich lake water demonstrated prolonged suppression of cyanobacteria, and displayed a remarkable stability of the newly developed post-HP treatment state of the phytoplankton community.

Existing and emerging cyanocidal compounds: new perspectives for cyanobacterial bloom mitigation

“…This fundamental idea suggested the mechanism why HP could act as a specific cyanocide which has earlier been demonstrated empirically (Barroin and Feuillade 1986). This hypothesis was thereafter successfully tested in the laboratory (Dráb-ková et al 2007a, b;Weenink et al 2015) and in the field (Matthijs et al 2012). The actual cyanobacteria killing compound may very well be not HP itself but a compound derived from HP, for which hydroxyl radical formation by UV light and catalysed by Fenton reaction active ions has been presented as a candidate by Huo et al (2015).…”

“…In the explanation of why some lakes were considered not adequate for treatment, we mention that the cell density of the phytoplankton, and the phytoplankton species composition in the water plays an important role. In particular, the presence of eukaryotic algae (green algae and diatoms, with both algal species bearing strong anti-ROS capacity) gives rise to a high rate of HP degradation, which effectively protects cyanobacteria in the phytoplankton against oxidative damage (Weenink et al 2015;Weenink et al unpublished results). Also colony morphology and EPS richness play a pronounced role in resistance of cyanobacteria to an attack by HP Gao et al 2015).…”

“…Most of all, it is stressed that for now the HP-based peroxide method for lake mitigation establishes a tool for suppression of cyanobacteria. Whether it can also be used to contribute sustainably to lake water restoration by providing conditions that help increase biodiversity (Weenink et al 2015) and that will accelerate reoligotrophication is topic of current research at the University of Amsterdam.…”

How to combat cyanobacterial blooms: strategy toward preventive lake restoration and reactive control measures

“…Hydrogen peroxide (H 2 O 2 ) is a potent algaecide and herbicide in general, but particularly selective for cyanobacteria (Barroin and Feuillade 1986; Ecol ( ) 50:541-576 561 et al 2007bMatthijs et al 2012;Weenink et al 2015 (Kay et al 1982a), and destroyed Planktothrix rubescens at 1.7 mg l -1 within a few hours (Barroin and Feuillade 1986). At 2 mg l -1 , Planktothrix agardhii was effectively and selectively targeted (Matthijs et al 2012).…”

“…Some mollusks (Physa sp., Dreissena polymorpha) are damaged at concentrations of 10 mg l -1 and above (Kay et al 1982a;Martin et al 1993;Schmidt et al 2006). To avoid damaging or killing nontarget species, end concentrations should be limited to 2.5 mg l -1 (Matthijs et al 2012), or 5 mg l -1 if decay rates in the lake water are high (Weenink et al 2015). Decay rates increase with algae biomass, metal concentrations, and irradiance (Drábková et al 2007a).…”