Cyanobacterial Potential for Restoration of Loess Surfaces through Artificially Induced Biocrusts

Abstract

Loess is a highly porous and easily erosive aeolian sediment covering approximately 10% of the Earth’s surface. The weak vegetation cover and high wind speeds in many of these regions make loess sediment the main source of dust in the atmosphere. Dust particles deteriorate air quality and affect soils, crops, water systems, and animal and human health. The commonly used method for combating desertification is revegetation. However, planting various vascular plant species in loess landscapes did not show any long-lasting positive effects. This study aims to assess the potential of cyanobacterial strains for the restoration of exposed loess surfaces through the assisted development of biological loess crusts (BLCs). Isolated cyanobacterial loess strains were screened for the traits (toxicity, biomass and polysaccharide production) desirable for their use in restoration purposes. By simulating semi-arid environmental conditions in specially designed chambers, the potential of cyanobacterial loess strains for assisted development of BLCs and the mechanisms of loess stabilization have been evaluated by chlorophyll a accumulation and microscopic examination. It was confirmed that cyanobacteria have the ability to interact with loess particles resulting in BLC formation, which keeps the particles immobilized and the sediment below the particles stabilized.

Assessment of Common Cyanotoxins in Cyanobacteria of Biological Loess Crusts

“…For example, strains isolated from terrestrial environments have recently been reported to produce an uncommon cyanotoxin apratoxin, the production of which was previously associated exclusively with marine environments [ 7 ]. Bioassays could be a great tool to examine the general toxicity of inoculants [ 27 , 73 ], which is especially important for the rehabilitation of degraded and desertified land by cyanobacterial inoculation, since the application of toxic cyanobacterial strains would be hazardous.…”

“…Loess deposits, because of their porous structure and extensive exploitation and degradation, are a significant source of airborne dust affecting people living in loess-rich areas. With a similar idea to the BLOCDUST hypothesis on the interaction between cyanobacteria and loess particles, artificial formation of BLC cover over the degraded loess surfaces by inoculation of cyanobacteria is proposed as a promising mechanism for their restoration [ 26 , 27 ]. The technology is based on the inoculation of laboratory-grown cyanobacteria on disturbed soil surfaces to establish soil particle stability, nutrient uptake, and circulation, and promote the establishment of higher vegetation [ 28 , 29 , 30 ].…”

“…The toxicity of cyanobacterial taxa within BLCs has only recently been addressed for the first time. In the two studies, one BLC sample [ 31 ] and one cyanobacterial strain isolated from a BLC [ 27 ] showed low toxicity to the Artemia salina larvae, indicating the necessity for further studies. This study aims to investigate cyanotoxin production in cyanobacteria-dominated BLCs and in cyanobacterial strains isolated from BLCs to address the following: 1. the extent of cyanotoxin production in cyanobacteria of BLC; 2. to avoid the application of potentially toxic strains in the restoration of deteriorated loess surfaces; 3. potential of cyanotoxins as a biosignature of cyanobacterial communities in paleoenvironmental research of loess.…”

Special Issue on Harmful Cyanobacteria and Their Metabolites

“…Not all cyanobacteria are harmful, and they perform crucial ecosystem services. Palanački Malešević et al assessed the potential of cyanobacterial inoculation for the restoration of damaged loess surfaces through assisted development of biological loess crusts (BLCs) [5]. A number of cyanobacterial strains were screened for desirable characteristics in the restoration process (lack of toxicity, and high production of biomass and polysaccharides).…”

Study on Soil Selenium-Induced Copper Deficiency in Yudong Black Goats

“…In Cu-deficient areas, ataxia in lambs can be as high as 30% in some areas. Although deaths were rare, sheep failed to thrive, resulting in severe economic losses [6][7][8]. Cu deficiency includes direct and induced deficiencies.…”