ABSTRACT
Globally, bacterial and fungal communities are important factions present in all major ecosystems with a significant role to play in driving various ecosystem functionalities. Given the differences in life style of these micro-organisms and their occurrence in all ecosystems, these pervasive micro-organisms tend to adapt/withstand harsh environmental conditions such as extreme highs and lows in abiotic/physical characteristics. Besides the potential of exhibiting physiological plasticity (special ability to utilizing non-photosynthetic substrates like methane, sulfur, and iron), in order to evolve and survive in extreme environments, they also respond to trivial changes in environment by exhibiting different patterns in abundance and diversity. Although, many studies have centered focus on studying micro-organisms in hostile conditions but the role of seasonal dynamics in shaping these microbial communities in extreme environments remains an open question. Of late, the different trends in abundance of fungi and bacteria and their functional diversity in the face of seasonal dynamics is gaining focus. Here we have discussed how bacterial and fungal assemblages are continually evolving into different adaptations in extreme conditions. The chapter explains contributions of abiotic conditions (temperature, pressure, pH, oxygen saturation, salinity) and biotic conditions (low nutrition, high population density, or low prey availability) in temporal and spatial dynamics of bacterial and fungal lineages in extreme environments.
