Microbial Mat Functional and Compositional Sensitivity to Environmental Disturbance

Abstract

The ability of ecosystems to adapt to environmental perturbations depends on the duration and intensity of change and the overall biological diversity of the system. While studies have indicated that rare microbial taxa may provide a biological reservoir that supports long-term 40 ecosystem stability, how this dynamic population is influenced by environmental parameters remains unclear. In this study, a microbial mat ecosystem located on San Salvador Island, The Bahamas was used as a model to examine how environmental disturbance affects the activity of rare and abundant archaeal and bacterial communities and how these changes impact potential biogeochemical processes. While this ecosystem undergoes a range of 45 seasonal variation, it experienced a large shift in salinity (230 to 65 g kg -1 ) during 2011-2012 following the landfall of Hurricane Irene on San Salvador Island. High throughput sequencing and analysis of 16S rRNA and rRNA genes from samples before and after the pulse disturbance showed significant changes in the diversity and activity of abundant and rare taxa, suggesting overall functional and compositional sensitivity to environmental 50 change. In both archaeal and bacterial communities, while the majority of taxa showed low activity across conditions, the total number of active taxa and overall activity increased postdisturbance, with significant shifts in activity occurring among abundant and rare taxa across and within phyla. Broadly, following the post-disturbance reduction in salinity, taxa within Halobacteria decreased while those within Crenarchaeota, Thaumarchaeota, Thermoplasmata, 55Cyanobacteria, and Proteobacteria, increased in abundance and activity. Quantitative PCR of genes and transcripts involved in nitrogen and sulfur cycling showed concomitant shifts in biogeochemical cycling potential. Post-disturbance conditions increased the expression of genes involved in N-fixation, nitrification, denitrification, and sulfate reduction. Together, our findings show complex community adaptation to environmental change and help 60 elucidate factors connecting disturbance, biodiversity, and ecosystem function that may enhance ecosystem models.

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

“…2015), Bahamas (Preisner et al. 2016), El Salvador, Guatemala (Miller et al. 2007) and Costa Rica (Uribe‐Lorío et al.…”

How environment selects: Resilience and survival of microbial mat community within intermittent karst spring Krčić (Croatia)

“…In these situations, the ability of ecosystems to adapt to the exerted changes depends on the duration and the intensity of the change, as well as on its biological diversity. In the study conducted by Preisner, Fichot, and Norman (), significant changes in diversity and shifts in biogeochemical cycling potential were recorded within microbial mats as a consequence of changes exerted to the ecosystem. Although nutrient level and physicochemical measurements (low COD, constant high oxygen saturation) confirmed Krčić as a pristine ecosystem, with year‐long oligotrophic nutrient status, at the same time, this river showed intense seasonal fluctuations in its water regime.…”

Comparative metagenomics of microbial mats from hypersaline lakes at Rottnest Island (WA, Australia), advancing our understanding of the effect of mat community and functional genes on microbialite accretion

“…Microbial mats are complex organosedimentary structures, usually organized as vertically stratified layers of specialized microbial consortia (Cantrell and Duval‐Pérez ; Wong et al ). They consist of self‐sustaining communities of bacteria, archaea and, to a lesser extent, eukarya and viruses (Prieto‐Barajas et al ; Suosaari et al ; Wong et al ), in which all major biogeochemical processes occur (Bolhuis et al ; Preisner et al ). Microbial mat communities are embedded in a self‐produced matrix of extracellular polymeric substances (EPS), wherein steep physicochemical gradients are created as a result of microbial community metabolism (Dupraz et al ; Jungblut et al ; Gutiérrez‐Preciado et al ).…”

“…These changes in the ancient atmosphere have influenced biological evolution by, for example, paving the way for oxygen‐dependent life (Dupraz et al ; Olson et al ). Modern microbial mats are considered relevant analogs of the early microbial mat ecosystems, hence, an important resource for studying the evolution of the ancient biosphere and biogeochemical cycles, and investigating microbial‐microbial and microbial‐environment interactions (Noffke et al ; Preisner et al ; Prieto‐Barajas et al ). For several decades, sedimentologists and geomicrobiologists have been studying these interactions to explain, for example, how microorganisms from microbial mats have shaped the planet's sedimentary record and their role in mineral precipitation (Peimbert et al ; Nutman et al ; Cabestrero and Sanz‐Montero ).…”