The Compositionally Distinct Cyanobacterial Biocrusts From Brazilian Savanna and Their Environmental Drivers of Community Diversity

Abstract

The last decade was marked by efforts to define and identify the main cyanobacterial players in biological crusts around the world. However, not much is known about biocrusts in Brazil's tropical savanna (cerrado), despite the existence of environments favorable to their development and ecological relevance. We examined the community composition of cyanobacteria in biocrusts from six sites distributed in the Southeast of the country using high throughput sequencing of 16S rRNA and phylogenetic placement in the wider context of biocrusts from deserts. Sequences ascribable to 22 genera of cyanobacteria were identified. Although a significant proportion of sequences did not match those of known cyanobacteria, several clades of Leptolyngbya and Porphyrosiphon were found to be the most abundant. We identified significant differences in dominance and overall composition among the cerrado sites, much larger than within-site variability. The composition of cerrado cyanobacterial communities was distinct from those known in biocrusts from North American deserts. Among several environmental drivers considered, the opposing trend of annual precipitation and mean annual temperature best explained the variability in community composition within Brazilian biocrusts. Their compositional uniqueness speaks of the need for dedicated efforts to study the ecophysiology of tropical savanna biocrust and their roles in ecosystem function for management and preservation.

Mining Subsidence-Induced Microtopographic Effects Alter the Interaction of Soil Bacteria in the Sandy Pasture, China

“…Cyanobacteria can adapt to hypoxic and oligotrophic environments (Figure 9), most of which can fix nitrogen (Percival and Williams, 2014), and can form biological soil crusts with algae and mosses (Ferrenberg et al, 2017), significantly improving surface soil nutrients and soil water holding capacity (Yang et al, 2012), etc. The biological crusts have strong physiological tolerance to adversity (Warren et al, 2019), and play an important role in improving the soil structure of the slope and the bottom of the slope, preventing soil erosion (Machado-de-Lima et al, 2019), and regulating the balance of precipitation infiltration and evapotranspiration (Moreira-Grez et al, 2019). Euryarchaeota is characterized by living in extreme environments (such as high salinity, high temperature and hypoxia) (Barberan et al, 2011), and a large number of ammonia oxidation functions are used to cope with the poor soil nutrients caused by mining subsidence (Schleper and Nicol, 2010).…”

Niche Partitioning with Temperature among Heterocystous Cyanobacteria (Scytonema spp., Nostoc spp., and Tolypothrix spp.) from Biological Soil Crusts

“…and Nostoc spp. In places such as the Colorado Plateau, the Mojave desert, the north part of the Chihuahuan Desert (Sevilleta LTER) in the USA, Alicante in Spain, Western Australia [49], temperate areas in Mexico [33], and the Brazilian savannah (Cerrado) [52], where the mean annual temperature during the growth season falls between the 17 and 23 • C range, this microbial replacement will likely happen faster than at those locations exhibiting mean average temperatures below 17 • C, that are not projected to reach sensitive temperature ranges for decades to centuries, or locations with average temperatures above 24 • C, which already exhibit a dominance of Scytonema spp. (Figure 4).…”

“…We performed a literature search, and either downloaded from public databases or directly requested raw sequence data from authors from multiple environmental biocrust surveys conducted at different locations around the world. We collected data from different arid and semiarid regions in USA [6,34,[46][47][48], Mexico [33] and Australia [49], from arid, semiarid and alpine regions in Europe [32,50], from the arid Gurbantunggut desert in China [51], and from the Brazilian savannah (Cerrado) [52]. A complete list of the biocrust surveys with locations, environmental variables, and other relevant information can be found in Table S4.…”

Coleofasciculaceae, a Monophyletic Home for the Microcoleus steenstrupii Complex and Other Desiccation‐tolerant Filamentous Cyanobacteria

“…2018, Machado‐de‐Lima et al. 2019, Muñoz‐Martín et al. 2019) that used molecular surveys through Illumina MiSeq 16S rRNA gene (relatively short sequences, ˜300 bp) and included locations from Europe and the Americas.…”

“…2016), and from the Brazilian savanna (Machado‐de‐Lima et al. 2019). A complete list with relevant metadata is in Table in the Supporting Information.…”