Mapping Microbial Genomes through Time and Space in the Arctic Ocean

Boulton, William (2026) Mapping Microbial Genomes through Time and Space in the Arctic Ocean. Doctoral thesis, University of East Anglia.

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Abstract

The Arctic Ocean acts as a leading indicator for the microbial response to the changing ocean climate, and hosts a wealth of microbial diversity, much of which is of unknown composition. Microbes play an important role as primary producers and base of the marine food web, in the carbon cycle, and in other biogeochemical cycles. They are also a source of novel genes, many of which are of interest to the biotechnology industry. It is therefore important to understand the effect of changing environmental conditions on these organisms and their genes. However, due to the extreme inaccessibility of the central Arctic, there is a gap in our understanding of microbial communities in the region.

To study these communities, we analyse datasets from the Multidisciplinary Drifting Observatory for Study of the Arctic Climate (MOSAiC) expedition. MOSAiC was the longest ever Arctic expedition, and the first to observe the Arctic throughout an annual cycle.

The aim of this thesis is to catalogue the Arctic microbial diversity captured by MOSAiC in the form of metagenomes, i.e. DNA from environmental samples. We focus on metagenome-assembled genomes (MAGs); putative semi-complete genomes derived from metagenomes computationally. MAGs are useful since most microbial species are too numerous, and too difficult to isolate, culture, and sequence individually. We develop a computational pipeline to recover prokaryotic and eukaryotic MAGs, and a new method to visualise eukaryotic MAGs and improve their quality.

We also quantify the microbial diversity recovered from MOSAiC across different environments, including a huge number of novel genera and species, and identify species cooccurrence patterns, functional profiles, and diversification of important gene families, with an emphasis on MAGs as operational taxonomic units. We found highly distinct sea ice and seawater communities, with temporal abundance profiles dictated by seasonal changes. In the final chapter we describe avenues for future research, using the MAG catalogue as a foundation to model and predict microbial communities in a changing Arctic climate.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Computing Sciences
Depositing User:	Chris White
Date Deposited:	21 May 2026 08:25
Last Modified:	21 May 2026 08:25
URI:	https://ueaeprints.uea.ac.uk/id/eprint/103120
DOI:

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