The influence of temperature and pH on bacterial community composition of microbial mats in hot springs from Costa Rica

Abstract

We used the 16S rRNA gene pyrosequencing approach to investigate the microbial diversity and community composition in several Costa Rican hot springs alongside the latitudinal axis of the country, with a range of temperatures (37–63°C), pH (6–7.5) and other geochemical conditions. A principal component analyses of the physicochemical parameters showed the samples were separated into three geochemically distinct habitats associated with the location (North, Central, and South). Cyanobacteria and Chloroflexi comprised 93% of the classified community, the former being the most abundant phylum in all samples except for Rocas Calientes 1, (63°C, pH 6), where Chloroflexi and Deinococcus‐Thermus represented 84% of the OTUs. Chloroflexi were more abundant as temperature increased. Proteobacteria, Bacteriodetes and Deinococcus‐Thermus comprised 5% of the OTUs represented. Other Phyla were present in very small percentages (<1%). A LINKTREE analysis showed that the community structure of the mats was shaped primarily by pH, separating samples with pH > 6.6 from samples with pH < 6.4. Thus, both pH and temperature were relevant for community composition even within the moderate ranges of variables studied. These results provide a basis for an understanding of the physicochemical influences in moderately thermophilic microbial mats.

Novel Cyanobacterial Diversity Found in Costa Rican Thermal Springs Associated with Rincon de la Vieja and Miravalles Volcanoes: A Polyphasic Approach

“…(2008) and Uribe‐Lorío et al. (2019) reported that Costa Rican thermophilic Fischerella grow at temperatures range from 35 to 60°C (similar conditions observed in Miravalles). Fischerella L38 is the same RV14 strain isolated by Finsinger et al.…”

“…2011), Uribe‐Lorío et al. (2019) found this genotype in the Rocas Calientes thermal springs growing at 63°C in Costa Rica.…”

“…2017, Uribe‐Lorío et al. 2019). Based on our results, the temperature tolerance (74°C) of Synechococcus C1 genotype was higher than previously reported (63°C), interestingly, also in Costa Rica.…”

Meta-Analysis of Microbial Communities in Hot Springs: Recurrent Taxa and Complex Shaping Factors beyond pH and Temperature

“…To analyze the relevance of pH and temperature as driving factors of the microbial community, and also to search for frequent taxa in these environments, we collected amplicon sequence data from other hot springs around the world. Most of the studies present conflicting reports as to whether pH or temperature is the major shaping factor [ 4 , 5 , 6 , 9 , 10 ]. On the other hand, some authors have proposed other significant variables.…”

“…It has also been reported that extreme conditions decrease the biodiversity [ 7 , 8 ]. However, it may not be that simple, as Power et al [ 9 ] and Uribe-Lorio et al [ 10 ] have shown that pH has a strong influence in the communities’ structure, since the samples in both studies could be split in two clusters: one with acidic pH and the other one with circumneutral conditions. Power et al [ 9 ] also showed that temperature influence was significative only at values above 70 °C, which suggests that other explicatory variables may arise if the range considered for pH and temperature is narrow.…”