My project utilises a wide variety of techniques to discern the environmental drivers most impacting the decomposition of kelp, and what this means for the transport and deposition of detrital material in offshore sediments.

Kelp forests dominate temperate shorelines, with high annual turnover of biomass that supports a diverse range of species through grazing, wave dampening and providing nursery grounds. Of high research interest more recently, is the role of kelp in carbon sequestration. With no root system to sequester carbon directly into sediment, kelp serve as carbon donors when detrital material is transported to neighbouring or offshore sediments. My target species are: Saccharina latissima, Laminaria hyperborea and Laminaria digitata.

My QUB Pure profile

Firstly, a tank experiment investigates the concurrent effect of water motion and raised temperature on the release of dissolved organic carbon from 2 dominant kelp species in both winter and summer. An oscillating frame powered by a motor allows the simulation of water motion within half the tanks, while the others remain static. Half of each movement treatment are fitted with aquaria heaters to raise sea water temperature.

Secondly, metabarcoding has been used to identify a range of Phaeophyceae (brown seaweed) species, including my 3 target kelp species in sediment and water samples collected across the Irish Sea. The primers used were also able to detect a wide range of fungi, phytoplankton and other species that allow very interesting discussions and analyses to be conducted on their role in detrital pathways. Lastly, samples collected in both a lab experiment and from the Irish Sea have been extracted to analyse fatty acid composition as another means of identifying brown seaweed detritus. These can be drawn into the discussion of the metabarcoding results to increase our understanding of source to sink relationships. In addition to ocean chemistry and trawling activity data provided by AFBI to provide in-depth insight into the variables underpinning each sample site and what this means for management of stakeholder interests.