Functional biology and ecology of aquatic fungi.

Fungi are well established as important components of aquatic ecosystems, however the functional roles that they fulfil remain poorly understood (Grossart & Rojas-Jimenez 2016). Recently, we have shown that fungi in marine waters regularly form blooms linked to specific environmental drivers, including particulate organic carbon (POC) availability (Taylor et al 2016). In a separate study using 13C-labelled diatom produced POC, we have identified specific aquatic fungi involved in POC cycling (Cunliffe et al 2017). These studies show that some aquatic fungi are saprotrophic, degrading POC via extracellular enzymes and feeding on dissolved organic degradation products osmotrophically.
Understanding the fundamental mechanisms that underpin biogeochemical processes in model microorganisms, including using 'omics tools, is powerful and can reveal novel insights into microbial functioning in ecosystems. At present there are no model aquatic fungi available to understand fungal saprotrophy and POC cycling. This represents a knowledge gap that should be addressed in order to fully understand the functional roles that fungi fulfil in aquatic ecosystems.

The overarching aim of this PhD project is to utilise a new model fungus to understand the fundamental mechanisms that underpin aquatic fungal saprotrophy and particulate organic carbon (POC) cycling. The model has recently been developed in the Cunliffe Group at the Marine Biological Association (MBA) (paper in preparation). Preliminary analysis has shown that the fungus has a diverse range of novel POC-processing enzymes that will be assessed for their ecosystem functional roles and potential environmental biotechnological applications. Core resources developed include a genome sequence and established culturing techniques. These advances provide the platform for further experimentation to advance understanding of the ecology and biology of these important aquatic microorganisms. Experiments will determine how the fungus physically interacts with POC, including live cell imaging via confocal microscopy. The molecular machinery controlling POC degradation will also be assessed, including using 'omics and CRISPR-Cas9 gene knock-out approaches.