Investigating Spatial Patterns of Variability in Bacterial Communities Inhabiting Arid Avicennia marina Forests
Type
ThesisAuthors
Thomson, Timothy
Advisors
Jones, Burton
Committee members
Moran, Xose Anxelu G.
Pain, Arnab

Ellis, Joanne I.
Program
Marine ScienceDate
2019-06Embargo End Date
2019-07-08Permanent link to this record
http://hdl.handle.net/10754/655957
Metadata
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At the time of archiving, the student author of this thesis opted to temporarily restrict access to it. The full text of this thesis became available to the public after the expiration of the embargo on 2019-07-08.Abstract
Mangrove forests provide a suite of critical ecosystem services ranging from local to global scales.Soil conditions and associated micro-organisms play a fundamental role in maintaining these services, that include nutrient cycling, carbon sequestration and plant growth-promoting properties. Despite its importance, the microbial abundance and function of mangrove soil has received little effort in current research. On the ecotone between the land and the sea, mangrove soils are subject to high variability of geomorphological and ecological conditions that imply a strong distinction of ecological niches. These conditions can diversify the structure and function of the prevalent microbiome. To identify the structure of bacterial communities of mangrove soils, 16S rRNA gene sequencing techniques were applied on samples from arid Avicennia marina forests across different spatial scales: (i) at different depths of the soil profile(surface/subsurface); (ii) between two distinct zones within a given forest (seaward/landward); (iii) among forests with varying local hydrodynamic conditions (exposed/sheltered); and (iiii) among forests in different geographic regions (Saudi Arabia and Australia). This study found that the bacterial soil community varied more within each forest than between forests in different countries. Notably, differences between countries became more apparent at the finest taxonomic resolution (ASVs). Bacterial communities from the landward zone of the mangrove forest are more conserved across countries than those from the dynamic seaward zone. Theoretically assigned functions showed high levels of sulfate respiration and chemoheterotrophy as major metabolic pathways. Differences across local factors in the functional traits reflect the within forest variability. The distinct microbial assemblages from the landward zone were associated with high salinity and phosphorus, and nitrogen and larger grain size were associated with the seaward samples. Understanding patterns of microbial communities in mangrove soils is important to predict changes and mitigate anthropogenic pressures on the ecosystem.Citation
Thomson, T. (2019). Investigating Spatial Patterns of Variability in Bacterial Communities Inhabiting Arid Avicennia marina Forests. KAUST Research Repository. https://doi.org/10.25781/KAUST-07O2Zae974a485f413a2113503eed53cd6c53
10.25781/KAUST-07O2Z