Biodiversity of Algae and Cyanobacteria in Biological Soil Crusts Collected Along a Climatic Gradient in Chile Using an Integrative Approach

Abstract

Biocrusts are associations of various prokaryotic and eukaryotic microorganisms in the top millimeters of soil, which can be found in every climate zone on Earth. They stabilize soils and introduce carbon and nitrogen into this compartment. The worldwide occurrence of biocrusts was proven by numerous studies in Europe, Africa, Asia and North America, leaving South America understudied. Using an integrative approach, which combines morphological and molecular characters (small subunit rRNA and ITS region), we examined the diversity of key biocrust photosynthetic organisms at four sites along the latitudinal climate gradient in Chile. The most northern study site was located in the Atacama Desert (arid climate), followed by open shrubland (semiarid climate), a dry forest region (Mediterranean climate) and a mixed broad leaved-coniferous forest (temperate climate) in the south. The lowest species richness was recorded in the desert (18 species), whereas the highest species richness was observed in the Mediterranean zone with (40 species). Desert biocrusts were composed exclusively of single-celled Chlorophyta algae, followed by cyanobacteria. Chlorophyta, Streptophyta and cyanobacteria dominated semiarid biocrusts, whereas Mediterranean and temperate Chilean biocrusts were composed mostly of Chlorophyta, Streptophyta and Ochrophyta. Our investigation of Chilean biocrust suggests high biodiversity of South American biocrust phototrophs.

The Ecophysiological Performance and Traits of Genera within the Stichococcus-like Clade (Trebouxiophyceae) under Matric and Osmotic Stress

“…If this is true, then Stichococcus and the newly erected genera Protostichococcus, Deuterostichococcus, Tritostichococcus, and Tetratostichococcus may occupy a similar niche as aeroterrestrial algae within the Prasiolaceae. This fits their profile as generalists that are able to colonize arid habitats worldwide as well as those exposed to some saline stress, such as in biocrusts on sand dunes [38], deserts [2], and potash piling heaps' surroundings [27,39]. However, the performance of cultures should ultimately be compared to that of environmental samples to provide information on their ecology.…”

“…Terrestrial algae, abundant in both extreme and temperate environments, are exposed to several abiotic stressors related to their habitat outside the aquatic environment such as UV radiation, freezing, and unpredictable water availability, where periods of drought of several weeks or even months punctuated by rains are common [ 1 , 2 , 3 ]. The subsequent success of terrestrial algae is partly due to their ability to withstand the stress of undergoing repeated and extended drying–rewetting cycles [ 4 ].…”

“…Various taxa within the Stichococcus -like genera of the Prasiolaceae (Trebouxiophyceae) are ubiquitous and abundant in diverse terrestrial habitats, such as tree bark [ 18 , 19 ], surfaces of buildings [ 20 , 21 , 22 ], biocrusts [ 2 ], and soil [ 23 ]. Due to their simple morphology and resemblance to one another, they have long been functionally grouped into the Stichococcus clade.…”

Broader Impacts for Ecologists: Biological Soil Crust as a Model System for Education

“…Similarly, this micro-ecosystem can be scaled all the way to global processes and global change drivers. This could include discussions of how and why different biocrusts live in different climates (Samolov et al, 2020), how biocrusts interact with the living and abiotic landscapes around them (Rodriguez-Caballero et al, 2019), and how their activities at the small scale could be affecting function at the global scale (Ferrenberg et al, 2017).…”

Impacts of Endocrine Disruptor di-n-Butyl Phthalate Ester on Microalga Chlorella vulgaris Verified by Approaches of Proteomics and Gene Ontology

“…Microalgae are a large and diverse group of aquatic organisms which can be found in freshwater, estuarine, and marine environments [ 1 , 2 ]. Compared to vascular plants of the same footprint, microalgae are potential candidates for biofuel production due to their high photosynthetic efficiency, high biomass yield, fast growth rate, and high applicability [ 3 ].…”