Underestimated cyanobacterial diversity: trends and perspectives of research in tropical environments

Abstract

Cyanobacteria are photo-oxygenic prokaryotes present in nearly all ecosystems, where they are important in global oxygen, carbon, and nitrogen cycles. They are often recognized as the harbingers of eutrophication in freshwater systems and are increasingly being noted as nuisance species in marine ecosystems such as coral reefs. In recent years, cyanobacteria have been intensely studied due to their toxicity, harmful bloom formation, and because their distribution and abundance are expected to increase with climate change. Nevertheless, for all of their importance, many gaps in our knowledge of cyanobacteria remain: the distribution, dispersal, and biogeography of these microorganisms are still not understood. Until 1994 little attention was paid to tropical cyanobacteria and their diversity, despite some harmful invasive species having their putative origins in tropical habitats. However, more practiced articulation and research has recently uncovered previously undescribed biodiversity, and in turn changed our knowledge of the evolutionary relationships within the Cyanobacteria. The purpose of this paper is to describe the challenges of working with the cyanobacteria and to review what we know of them from tropical habitats.

New cyanobacterial genus Argonema is hiding in soil crusts around the world

“…The diversity of cyanobacteria has been most thoroughly studied in temperate regions, especially in Europe and Northern America 10 – 12 . However, there are regions where the diversity of soil cyanobacteria remains largely unexplored, especially tropical 11 and polar regions 13 . This difference is likely due to the under-sampling, as a majority of cyanobacteriological studies focus on temperate regions and plankton 11 .…”

“…However, there are regions where the diversity of soil cyanobacteria remains largely unexplored, especially tropical 11 and polar regions 13 . This difference is likely due to the under-sampling, as a majority of cyanobacteriological studies focus on temperate regions and plankton 11 . Moreover, only ~ 20% of species in the GenBank are correctly identified and at least half of cyanobacterial species have never been successfully cultured 14 .…”

Phylogeny and fatty acid profiles of Aliinostoc vietnamicum sp. nov. (cyanobacteria) from the soils of Vietnam

“…In recent years, the number of new taxonomic units is increasing due to research in tropical environments (Dvořák et al. 2021) such as Minunostoc (Cai et al. 2019), Violetonostoc (Cai et al.…”

“…While 5 new genera were found in India, 6 from China, and 21 from Brazil including 7 soil forms in total (Dvořák et al. 2021). Today we are seeing limited insights into the diversity of Nostocaceae in Vietnam's biomes.…”

Scarus spinus, crustose coralline algae and cyanobacteria: an example of dietary specialization in the parrotfishes

“…This cryptic cyanobacterium has been reassigned to the genus Leptolyngbya (Komárek 2007;Roush and Garcia-Pichel 2020), a taxon containing endolithic members (Horath and Bachofen 2009). Cyanobacterial taxonomy is in a state of flux (Komárek 2018;Engene et al 2018;Dvořák et al 2021). For example, molecular sequencing reassigned Lyngbya majuscula to at least six new genera (Nuryadi et al 2020).…”