Global distribution and diversity of marine euendolithic cyanobacteria.

Euendolithic, or true-boring, cyanobacteria actively erode carbonate-containing substrata in a wide range of environments and pose significant risks to calcareous marine fauna. Their boring activities cause structural damage and increase susceptibility to disease and are projected to only intensify with global climate change. Most research has, however, focused on tropical coral systems, and limited information exists on the global distribution, diversity, and substratum specificity of euendoliths.

Swapping Metagenomics Preprocessing Pipeline Components Offers Speed and Sensitivity Increases.

Increasing data volumes on high-throughput sequencing instruments such as the NovaSeq 6000 leads to long computational bottlenecks for common metagenomics data preprocessing tasks such as adaptor and primer trimming and host removal. Here, we test whether faster recently developed computational tools (Fastp and Minimap2) can replace widely used choices (Atropos and Bowtie2), obtaining dramatic accelerations with additional sensitivity and minimal loss of specificity for these tasks. Furthermore, the taxonomic tables resulting from downstream processing provide biologically comparable results.

Fast and accurate distance-based phylogenetic placement using divide and conquer.

Phylogenetic placement of query samples on an existing phylogeny is increasingly used in molecular ecology, including sample identification and microbiome environmental sampling. As the size of available reference trees used in these analyses continues to grow, there is a growing need for methods that place sequences on ultra-large trees with high accuracy. Distance-based placement methods have recently emerged as a path to provide such scalability while allowing flexibility to analyse both assembled and unassembled environmental samples.

Cydrasil 3, a curated 16S rRNA gene reference package and web app for cyanobacterial phylogenetic placement.

Cyanobacteria are a widespread and important bacterial phylum, responsible for a significant portion of global carbon and nitrogen fixation. Unfortunately, reliable and accurate automated classification of cyanobacterial 16S rRNA gene sequences is muddled by conflicting systematic frameworks, inconsistent taxonomic definitions (including the phylum itself), and database errors. To address this, we introduce Cydrasil 3 ( https://www.

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

Cyanobacteria classified as Microcoleus steenstrupii play a significant role as pioneers of biological soil crusts (biocrusts), but this taxon is recognized to constitute a diverse complex of strains and field populations. With the aim of clarifying its systematics, we conducted a polyphasic characterization of this and allied taxa. A 16S ribosomal gene meta-analysis of published environmental sequences showed that the complex encompasses a variety of well supported genus-level clades with clade-specific environmental preferences, indicating significant niche differentiation.

Succession and Colonization Dynamics of Endolithic Phototrophs within Intertidal Carbonates.

Photosynthetic endolithic communities are common in shallow marine carbonates, contributing significantly to their bioerosion. Cyanobacteria are well known from these settings, where a few are euendoliths, actively boring into the virgin substrate. Recently, anoxygenic phototrophs were reported as significant inhabitants of endolithic communities, but it is unknown if they are euendoliths or simply colonize available pore spaces secondarily.

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

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 (), 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.

A New Niche for Anoxygenic Phototrophs as Endoliths.

Anoxygenic phototrophic bacteria (APBs) occur in a wide range of aquatic habitats, from hot springs to freshwater lakes and intertidal microbial mats. Here, we report the discovery of a novel niche for APBs: endoliths within marine littoral carbonates. In a study of 40 locations around Isla de Mona, Puerto Rico, and Menorca, Spain, 16S rRNA high-throughput sequencing of endolithic community DNA revealed the presence of abundant phylotypes potentially belonging to well-known APB clades.

Exposure to predicted precipitation patterns decreases population size and alters community structure of cyanobacteria in biological soil crusts from the Chihuahuan Desert.

Cyanobacteria typically colonize the surface of arid soils, building biological soil crust (biocrusts) that provide a variety of ecosystem benefits, ranging from fertilization to stabilization against erosion. We investigated how future scenarios in precipitation anticipated for the Northern Chihuahuan Desert affected abundance and composition of biocrust cyanobacteria in two grassland ecosystems. Scenarios included a decrease in precipitation and a delay of monsoon rainfall.