Cyanobacterial Composition of Microbial Mats, Found in Brejo do Espinho and in Artificial Saline of Araruama, RJ, Brazil

Abstract

Microbial mats are organo-sedimentary ecosystems formed by autotrophic and heterotrophic bacterias. Cyanobacteria contribute to the formation of these structures from the entrapment and engulfment of sediments contributing to the formation of carbonate rocks found in the geological record from the Precambrian to the Recent. In this research we identified the living cyanobacteria mats type 1 (gelatinous) and type 2 (cohesives) present in Brejo do Espinho and Araruama saline, east Fluminense, Rio de Janeiro state. The microbial mats type 1, were found in compartiment A and B of Brejo do Espinho and the Araruama saline in the tank with a depth of 10 cm. The mats type 2 were only found in compartiment A and in tank with 15 cm depth. In the microbial mats of compartiments A and B predominated the spherical forms of genres Chroococcus Nägeli 1948 and Aphanothece Nägeli 1948. In the tanks predominated filamentous forms of the Leptolyngbya Anagnostidis and Komárek 1988 genre. In mats type 1, the diversity indices (H') were 1.95 and 2.24 and in type 2 of 2.16 and 2.14 for the Brejo do Espinho and Araruama saline, respectively. The highest values of diversity indices found in saline tanks occurred by stable salinity conditions.

Salinity matters the most: How environmental factors shape the diversity and structure of cyanobacterial mat communities in high altitude arid ecosystems

“…In the other study on hypersaline mats ( Abed et al, 2011 ) the main mat-building cyanobacterium was Microcoleus chthonoplastes ( Coleofsciculus chtonoplastes ). The occurrence of Leptolyngbya in hypersaline mats was noted by other authors, but contribution of this genus was low ( Feder et al, 2013 ; Wong et al, 2015 ; Ramos et al, 2017 ). Thus, the dominance of Leptolyngbya in the hypersaline and sub-dominance in other highly saline mats in Pamir seems to be quite a unique feature distinguishing them from others observed in hypersaline environments.…”

“…In general, authors divided microbial mats on the basis of environmental characteristics, such as the hypersaline, coastal, oligotrophic, psychrophile, hot springs, and acid microbial mats ( Prieto-Barajas et al, 2018 ). Others divided the mats according to their macromorphology ( Feder et al, 2013 ). In our study, having a very high morphological variety of mats, we divided them according to their macromorphology into eight types.…”

Microbial Mat Microbiofacies Analysis of the Pitanguinha Lagoon (Região dos Lagos, RJ, Brazil)

“…Já no Brejo do Espinho, dois tipos de esteiras gelatinosas (ou poligonais) foram identificadas, basicamente pela constituição microbial de suas lâminas multicoloridas (Delfino et al, 2012;Feder et al, 2013), ambas descritas anteriormente como uma esteira lisa estratificada, pela presença dessas lâminas multicoloridas características (Silva et al, 2007b). Na Lagoa Pernambuco, pequenos estromató-litos dos tipos "colunar", "domal" e "contínuo" são observados (Silva et al, 2004b), além de todos os sete tipos de esteiras microbianas (Iespa & Silva, 2005;Iespa et al, 2006;Silva et al, 2004b) da classificação de Hoffman (1976).…”