Environmental gradients exist at global and local scales and the variable conditions they
encompass allow the coexistence of different microbial assemblages. Studying gradients
and the selection forces they enclose can reveal the spatial succession and interactions of
microorganisms and, therefore, how they are assembled in functionally stable
communities. By combining high-throughput sequencing technology and laboratory
experimental approaches, I investigated the factors that influence the microbial community
assemblages in two types of environmental gradients in the Red Sea. I have studied the
communities in the chemoclines occurring at the transition zones along the interfaces
between seawater and the Deep Hypersaline Anoxic Brines (DHABs) at the bottom of the
Red Sea. Across these chemoclines salinity increases of 5-10 times respect to the overlying
seawater. I compared the microbial community diversity and metabolisms in the
chemoclines of five different DHABs, finding different microbial community
compositions due to the different DHABs characteristics, but the same succession of
metabolisms along the five interfaces. From the Suakin Deep brine, I assembled the
genome of a novel bacterial phylum and revealed the metabolic features that allow this
organism to cope with the challenging variable conditions along the chemocline. In an
alternative environmental system, I studied the effect of different thermal regimes on the
microbiome of coastal sediment exposed to different yearly ranges of temperature
variation. Sediment bacterial communities living under larger temperature variations are
more flexible and can grow under a larger range of thermal conditions than communities
experiencing narrower temperature ranges. My results highlight the large metabolic
flexibility of microorganisms and their capacity to efficiently self-organize in complex
functional assemblages under extreme ranges of environmental conditions.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/661762 |
| Date | 02 1900 |
| Creators | Barozzi, Alan |
| Contributors | Daffonchio, Daniele, Biological and Environmental Sciences and Engineering (BESE) Division, Moran, Xose Anxelu G., Pain, Arnab, Borin, Sara |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Rights | 2021-02-27, At the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation will become available to the public after the expiration of the embargo on 2021-02-27. |
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