Application of Organic Superabsorbent Cellulosic Polymers ( OSCPs ) and Cyanobacteria on Reduction of Aeolian Losses

ABSTRACT

Establishing biocrusts on sandy surfaces in harsh desert environments presents significant challenges due to extreme ecological conditions. To address these challenges, this study examined the effects of two organic superabsorbent cellulosic polymers (OSCPs)—carboxymethyl cellulose (CMC) and guar gum (GUA)—on the establishment of cyanobacterial crusts on aeolian sands, specifically using a consortium of Nostoc sp. and Microcoleus vaginatus . The optimal concentrations of GUA and CMC for maximum cyanobacterial growth were determined through preliminary optimization assays. The resulting suspensions, combining OSCPs and cyanobacteria, were applied to sandy substrates. After 60 days of inoculation, the cyanobacterial crusts were analyzed for exopolysaccharide (EPS) accumulation, chlorophyll a content, physical and chemical properties, shear strength, and compressive strength. Additionally, wind tunnel tests were conducted to measure aeolian mass flux under the different treatments. Results indicated that the cyanobacteria + CMC treatment outperformed all others, increasing chlorophyll a by 114% and EPS production by 108% to 280% depending on the EPS fraction. This treatment also enhanced organic carbon and nitrogen accumulation, crust thickness (~21 mm), shear strength (51.39 kPa), and available water capacity (+110%). Furthermore, it raised the wind erosion threshold velocity from 11.5 to 19.7 m s ⁻¹ , reducing aeolian mass flux by over 98% at wind speeds up to 19.7 m s ⁻¹ . In contrast, GUA alone resulted in the lowest compressive strength and mass flux rates. These findings suggest that combining cyanobacteria with OSCPs, particularly CMC, is an effective strategy for promoting biocrust formation and mitigating soil erosion in arid environments.