Anthony Scales


The microbiota of maerl has the potential to contain diverse communities of bacteria which are thought to aid in maintaining maerl health and potentially be a driving factor in the settlement and development of ecological and economical important bi-valve species. However, little is currently known regarding the composition and structure of these communities, leading to uncertainty of their importance and their direct association to maerl beds. Using 16s amplicon sequencing analysis, the bacterial community composition associated with live and dead maerl (Phymatolithon calcareum) has been examined and compared to the communities associated with those of the surrounding environment - adjacent sediments and overlaying seawater. Four unique communities were present on the following samples: two associated with each of the surrounding environments (overlaying seawater and adjacent sediments), one associated with live and dead whole maerl nodules and the remaining observed on the surface layers of living maerl nodules. Sediment communities were seen to contain the most diversity, with enriched members of Moraxellaceae and Desulfobulbaceae present. Seawater communities in comparison harboured the lowest diversity and was dominated with members from Clade_I, Flavobacteriaceae, Rhodobacteraceae. Dead and living maerl nodules contained similar communites to one another with increased members of Flavobacteriaceae, Pirellulaceae, Nitrosopumilaceae witnessed across both types of nodules. Surface layers of the living maerl nodule contained a unique community compared to the that of the living whole nodule, enriched with members of Flavobacteriaceae, Rhodobacteraceae, Vibrionaceae. This thesis concludes that maerl beds studied in the Fal estuary contain two unique bacterial communities. Whilst the analysis of bacterial functions is beyond the scope of this study, it is highly speculated that members of either community are providing vital ecological roles in supporting the maerl bed and other associated species observed within maerl habitats. It is therefore the authors belief that greater protection should be afforded to maerl beds to protect ecological and economic interests.

Document Type


Publication Date




Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.