Artificial biocrust establishment on materials of potash tailings piles along a salinity gradient

Abstract

Biocrust communities provide a pallet of ecosystem services, such as soil stabilization, altering of hydrological cycles and primary production, and often are the first colonizers of unvegetated surfaces during succession. Therefore, artificially establishing biocrusts can improve soil properties, for example, by stabilizing bare soil surfaces against erosion or by accumulating nutrients. In this study, the establishment of artificial biocrusts was tested for the restoration of potash tailings piles that result from potash fertilizer production and mostly consist of NaCl. A biocrust cover as primary vegetation could decrease the saline seepage waters by trapping rainwaters, thereby reducing the environmental pollution. In a laboratory experiment, we created a salt gradient by mixing the tailings materials with non-saline dune sand. Surface material of the abandoned potash tailings pile Neuhof-Ellers (NE) and material of the Infiltration Hampering Stratum (IHS) were tested, along with a treatment with bone charplus (BCplus) and sodium alginate. A mixture of 50% (w/w) IHS and dune sand was most successful for the establishment of green biocrust microalgae, based on increased biomass and photosynthetic performance. The chlorophyll a content was negatively correlated with the electrical conductivity (EC), and was significantly increased in the BCplus and sodium alginate treatment, while biocrusts failed to establish on pure tailings piles substrates. The limit of the substrates EC for biocrust establishment was 35 mS cm−1. This limit provides a baseline for future studies that should use BCplus and sodium alginate to increase the success of biocrust establishment on potash tailings piles.

Salty Twins: Salt-Tolerance of Terrestrial Cyanocohniella Strains (Cyanobacteria) and Description of C. rudolphia sp. nov. Point towards a Marine Origin of the Genus and Terrestrial Long Distance Dispersal Patterns

“…is used [ 57 ], which shows great abilities in concatenating soil particles as a pioneer microbe. Recently, similar approaches have been undertaken with eukaryotic green algae that were used as inoculum in order to colonize and stabilize potash piles [ 58 ]. However, the two Cyanocohniella strains are also suitable for such purposes and additionally have the advantage that they can fix atmospheric nitrogen, which enriches soil fertility and thus can speed up remediation processes.…”

Biocrust diversity enhances dryland saline soil multifunctionality

“…Biocrust species richness can promote soil biological functions by facilitating soil microbial colonization in salinized drylands in two ways: First, biocrusts facilitate nutrient cycling and soil organic matter inputs (Barger et al, 2016; Duran et al, 2021) and consequently enhance soil nutrient functions (Figure 4b). Second, biocrusts provide more favourable microsites by enhancing infiltration, soil water content (soil hydrological functions), and reducing soil salinity compared to adjacent saline bare soils (Kakeh et al, 2020; Sommer et al, 2021). Therefore, biocrusts indirectly relieve water and nutrient limitations and salinity stress for soil microbes and their activities (Delgado‐Baquerizo et al, 2016).…”

“…The strong association between biocrust species richness and soil biological functions (Figure 4b) demonstrates that biocrusts promote soil microbial communities and microbial biomass (Su et al, 2021 4b). Second, biocrusts provide more favourable microsites by enhancing infiltration, soil water content (soil hydrological functions), and reducing soil salinity compared to adjacent saline bare soils (Kakeh et al, 2020;Sommer et al, 2021). Therefore, biocrusts indirectly relieve water and nutrient limitations and salinity stress for soil microbes and their activities (Delgado-Baquerizo et al, 2016).…”

Pseudostichococcus Stands Out from Its Siblings Due to High Salinity and Desiccation Tolerance

“…Halotolerant algae produce a wide variety of secondary metabolites beneficial to salinized agriculture [23] and may be utilized in bioremediation [21,24,62], including desalination [63]. P. monallantoides, which was successfully used to grow young biocrusts on saline substrates from potash tailing heaps [26]. Hence, the soil desalinization with this genus is not purely conjectural.…”

“…While halotolerant algae have chiefly been used to bioremediate saline waters and salinized soils, crop yield increase is also a growing field in applied phycology [12,[23][24][25]. However, recent work has shown that some algae were able to form young biocrusts on hypersaline potash tailing heaps, with ramifications for salinity bioremediation [26][27][28]. Among the organisms isolated form salt heaps were Chloroidium ellipsoideum, the cyanobacterium Nostoc, representatives from Stichococcus and Pseudostichococcus [27].…”