Place: Park Pobedi, Kazan, The Republic of Tatarstan, The Russian Federation.
Date: The treatment and follow up were conducted between October 2 and October 10 2018.
Setup: A local recreational lake with 40,000m2 surface area.
Application: Treatment with Lake GuardTM Blue (copper-based algicide) was broadcasted manually at 11:00am of October 2nd, from the banks of the lake by an untrained local. The application took less than 10 minutes. Once waterborne, the floating, slow-releasing particles were pushed by the wind and currents and organized themselves along cyanobacterial aggregations.
Water (250 ml) was collected immediately before applying the treatment (time 0); at 72 hours; and 120 hours after treatment by the Kazan State University. Samples were stored under no-light conditions and analyzed under a microscope. The microscopical analysis was composed of total-count of phytoplankton cell-density as well as total phytoplankton biomass. The latter is an additional and an important value in order to determine the effect of a given treatment over a variety of phytoplankton populations.
The lake was kept under regular observation for one year by the local superintendent.
Prior to treatment (time 0), the total phytoplankton cell density in the lake reached ~130,000 cells/L translating into a total biomass of 29 mg/L. With treatment, a significant reduction in total phytoplankton cell-density as well as biomass was measured over the first 4 to 6 days (a reduction of 65% and 78% respectively, Fig. 1A-B).
In terms of phytoplankton variety, prior to treatment, a single cyanobacterial specie, Aphanizomenon flos-aquae (L.)Ralfs, dominated the lake with a cell density of ~89,000 cells/L. Concurrently, other phytoplankton species in the ecosystem contributed <5% of the total cell-density (Fig. 2A). In terms of biomass, however, three species dominated the overall population, including Aphanizomenon sp., and two green algae species (Chlamydomonas sp. and Carteria sp.) (Fig. 2B).
Sampling at 72 hours and at time 120 hours after treatment showed a clear and significant 70% reduction of the toxic cyanobacterial species in both caterogries of cell-density and biomass values (Fig. 2). At the same time, Euglenic and Diatoms groups increased in numbers by 66% and 144% respectively, and in biomass by 120% and 66% respectively (Fig. 3).
Water turbidity did not change over the course of treatment and no adverse impact was observed to fauna or flora in or around the pond.
Based on reports from the local lake’s superintendent, for the remainder of 2018 going through September 2019(!), no bloom episodes have been registered in the lake, in clear contrast to past years. The rehabilitated condition of the lake allowed them, for the first time in years, to keep it open year-round for all recreational purposes.
A simple, cost-effective treatment with as little as ~0.33 PPM Lake GuardTM Blue surgically removed one dominant toxic species and enabled non-harmful, beneficial phytoplankton species to succeed the ecological niche and to further compete against the return of the toxic cyanobacteria throughout an entire season.
The dramatic shift between the toxic specie (cyanobacteria) to beneficial ones (green-algae) is a repeating motive in Lake Guard™ treatments throughout the world. Reshaping the balance of species in the water, in fact ‘restarts’ the disrupted ecological sphere, allowing it to keep a healthy balance between these coexisting species in the water naturally and uninterruptedly.
Fig. 2. Relative phytoplankton composition (%) at day 0 in values of (A) cell density, and (B) biomass. Notably, while in terms of cell density Aphanizomenon sp. dominated the pond, on the account of biomass (cell size), however, there were three species that were dominating the phytoplankton population included Aphanizomenon sp., and two green algae (Chlamydomonas sp. and Carteria sp.).