The effects of biocides on the growth of aerophytic green algae (Chlorella sp.) isolated from a cave environment

Abstract

Lampenflora communities of bacteria, cyanobacteria, algae, mosses and lichens colonize illuminated show-caves as a consequence of disturbances to the caves? ecological equilibrium. These communities have unesthetic impacts and can cause the biodeterioration of limestone. A 15% hydrogen peroxide solution was proposed for use as an ecological agent for the safe removal of these microorganisms. This study tested the effects of three different biocides (hydrogen peroxide, a commercial solution containing salicylic acid and a product containing chlorine dioxide as the active component), on the growth of green algae (Chlorella sp.), which are frequently encountered in lampenflora communities. Chlorella sp. was treated with the biocides under laboratory condition, and chlorophyll a (Chl a) concentrations were measured 1 h, 3 days, 7 days and 10 days after treatment. The change in Chl a concentration was compared to the untreated control group at each time point. All three biocides prevented the growth of green algae and the product containing chlorine dioxide appeared to be the most effective growth inhibitor. Hydrogen peroxide is known to suppress lampenflora growth in caves, and further studies on other biocides remain necessary to identify a solution that is both ecologically safe and economically feasible.

Unraveling disparate roles of organisms, from plants to bacteria, and viruses on built cultural heritage

“…However, positive results were obtained in laboratory assays using paired algal hosts ( Chlorella strains, NC64A, Pbi, and Sag 3.83) and viruses (PBCV-1, MT325, and ATCV-1) derived from aquatic systems, confirming the possibility of virus-induced bioremediation to inhibit growth of the alga Chlorella on stone. Chlorella commonly occurs on historic fountains and other wet stone surfaces (Bolivar-Galiano et al 2021 ) and also in lampenflora communities (Nikolić et al 2021 ).…”

16S and 18S rDNA Amplicon Sequencing Analysis of Aesthetically Problematic Microbial Mats on the Walls of the Petralona Cave: The Use of Essential Oils as a Cleaning Method

“…More specifically, using each of these approaches may increase the risk of spreading the contamination throughout the cave [9]. Lampenflora can strongly attach to abiotic surfaces and detach with difficulty, which can cause damage to cave walls and cave structures if not properly treated [1,10]. The growth of photosynthetic organisms can be significantly lowered by reducing the intensity of light and the use of special lamps that emit light at wavelengths different from the spectra of the absorption of Lampenflora [1].…”

“…The growth of photosynthetic organisms can be significantly lowered by reducing the intensity of light and the use of special lamps that emit light at wavelengths different from the spectra of the absorption of Lampenflora [1]. Another option is to use ultraviolet radiation, which has antimicrobial properties, but this is not a permanent solution as suppression of Lampenflora growth may not be sustained [9,10]. In contrast, ozone lamps are not very effective against Lampenflora.…”