Cyanobacterial Potential for Restoration of Loess Surfaces through Artificially Induced Biocrusts

Tamara Palanački Malešević,Rastko Marković,Bojan Kostić,Jussi Meriluoto,Tamara Dulić,Zorica Svirčev,Zorana Trivunović,Igor Obreht,Tamara Važić

doi:10.3390/app11010066

Tamara Palanački Malešević, Rastko Marković + Show 7 more

Open Access

https://doi.org/10.3390/app11010066

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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.

Highlights

Loess is an aeolian sediment with a homogeneous and porous structure that is eroded by wind and water
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)
BLCs were collected together with approximately 10 cm of sediment below them using a spatula, packed in storage bags, and transported to the laboratory where they were further used to isolate cyanobacterial strains. 1 cm2 of cyanobacterial BLCs were inoculated in the BG11 N− (BG11 without NaNO3) and BG11 N+ (BG11 supplemented with 1.5 g/L of NaNO3) media

Summary

Introduction

Loess is an aeolian sediment with a homogeneous and porous structure that is eroded by wind and water. It consists mainly of quartz particles (40–80%), and includes feldspars, micas, calcite and dolomite in lesser amounts, and heavy minerals in varying amounts [1]. Despite the importance and wide distribution of loess sediments, their mode of formation is not yet fully understood [7], and no model of their origin is yet fully accepted. The definition of loess sediment based on aeolian origin neglects processes involved in the transformation of dust particles into the stable loess sediment [7]. A significant process in loess formation is loessification, which includes postdepositional processes responsible for the transformation of wind-blown silt to loess [8]

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