Algal diversity of temperate biological soil crusts depends on land use intensity and affects phosphorus biogeochemical cycling

Abstract

Biological soil crusts (BSCs) form the most productive microbial biomass in many drylands and disturbed areas with a diverse 10 microalgal community as key component. In temperate regions, BSCs are also common, but generally less studied, and they conduct important ecological functions, like stabilization of soil and enrichment of nutrients. Changes in land use and its intensity strongly influence biodiversity per se and it's role for ecosystem processes, particularly in regions which are densely populated like Europe. But systematic studies on land use (i.e. management intensity) gradients in temperate forests on BSCs are missing up to now. To close this gap of knowledge and enhance the understanding of management effects on BSCs, 15Cyanobacteria and eukaryotic microalgae as key primary producers of these communities were identified from pine and beech forests under different management regimes. Algae were identified morphologically based on enrichment cultivation and categorized in either coccal taxa, which occur typically in high diversity, or filamentous taxa, which have the potential to initiate BSC formation. In total, 52 algal species were recorded, most from the phylum Chlorophyta, followed by Streptophyta and Heterokontophyta; Cyanobacteria were much less abundant in temperate forest BSCs. The most abundant crust-initiating 20 filamentous algae were three species of Klebsormidium (Streptophyta) a ubiquitous genus often associated with BSCs worldwide and a high tolerance to low pH. Increasing management intensity resulted in a higher richness of algae, especially the proportion of coccal algae rose. Furthermore, the proportion of inorganic phosphorus was positively correlated with the algal richness, indicating that higher diversity of algae results in a more closed P cycle. Thus, management of forests has an impact on the diversity of phototrophic organisms in BSCs, which in turn affects P cycling in the BSC. 25 key words: biological soil crusts, forest, management intensity, phosphorus, algae richness, Klebsormidium Biogeosciences Discuss., https://doi

Successional Development of the Phototrophic Community in Biological Soil Crusts on Coastal and Inland Dunes

“…This is in contrast with studies carried out in arid or semiarid deserts where cyanobacteria were always dominant in early successional biocrusts [12,31,38,74,75]. However, the presented findings are comparable to other studies conducted in temperate areas [76,77]. In temperate forests, Glaser et al [78] recorded 52 algal species and only very few cyanobacteria in biocrusts.…”

“…Glaser et al [78] could prove Klebsormidium was the most important biocrust-initiating alga in a temperate forest ecosystem. In an inland dune area in the Netherlands, Pluis [77] found Klebsormidium to be the initial green alga genus in the successional development of the biocrust community. Likewise, representatives of the genus Klebsormidium were found in dynamic dune successional stages along both transects, highlighting the initialization of biocrust development.…”

1030 - Structure and function of microbial communities at the soil atmosphere interface

“…Several studies have suggested substantial roles of soil crusts in arid regions in phosphorus cycling, particularly in the release of inaccessible organic-P (Crain et al, 2018, Glaser et al, 2017, Baumann et al, 2019. Significant enrichments in the abundance of genes assigned to phosphonate degradation were seen in the soil crust 208 relative to the bulk soil, which were on average 1.04-fold more abundant in the soil crust.…”

Diversity of Cyanobacteria and Algae in Biological Soil Crusts of the Northern Ural Mountain Region Assessed through Morphological and Metabarcoding Approaches

“…Microalgae and cyanobacteria are important components of these cryptogamic communities, playing a critical role in nutrient and nitrogen cycling and highly influencing soil oxygen and hydrological regimes. They are active in the top soil layer, forming a thin crust that helps to stabilize soil, maintain its structure, and protect against wind, thermokarst, and water erosions [1][2][3][4][5][6]. In extreme habitats such as alpine and polar ecosystems, where soils are often shallow and exposed, BSCs dominate, providing an important source of nutrition and water for small organisms that would otherwise struggle to survive.…”