Biography

I am a marine ecologist exploring the impacts of plastic pollution, potential cumulative effects with other anthropogenic stressors and how plastic pollution may impact the blue carbon pathway (carbon stored in marine ecosystems, which is sequestered from the atmosphere and oceans to the deep sea).

Increasing evidence shows that plastic pollution is bordering on a planetary boundary threat, which is a threat beyond which we cannot push the earths systems without putting society at risk. Plastic does not exist as a single stressor, but with a cocktail of other contaminants and climate stressors, such as ocean acidification, another planetary boundary threat. From an ecosystem health perspective, polar marine ecosystems may have higher sensitivity to anthropogenic stressors than other regions owing to the system’s physical and biological characteristics, and previous isolation of the ecosystem over evolutionary timescales.

Whilst potentially most vulnerable, the polar regions are also most critical to regulating our global climate. It is therefore pertinent we begin to understand the possible cumulative effects of these multiple oceanic stressors, which exist in parallel and are on the incline. This is paramount in sensitive and isolated systems, such as those of the Southern Ocean surrounding Antarctica. Consequently, there has never been a more important time to produce scientific data related to the emerging global stressor of plastic pollution, to aid associated polar conservation strategies and environmental policies.

During my PhD, I adopted an ecotoxicological approach, exploring the potential multi-stressor effects of plastic pollution and ocean acidification on a keystone polar zooplankton. Antarctic krill (Euphausia superba) embryos showed significantly reduced development under multi-stress conditions, compared to ambient seawater conditions which was not apparent when looking at nanoplastic or ocean acidification as single stressors. This work is a first step in highlighting the need to account for future climate driven changes to ocean conditions when considering the impact of plastic pollution in the Southern Ocean.

Another avenue of my PhD explored the vertical flux of microplastic which is virtually unknown. Globally, there is a 99% mismatch between plastic estimated to enter the marine environment and that what has been accounted for on the ocean surface. I calculated for the first time a vertical flux of plastic pollution in a high traffic area the Southern Ocean, demonstrating that microplastics are present through the water column, regardless of their buoyancy properties. Vertical plastic fluxes could therefore account for a proportion of ‘missing’ oceanic plastic not found at the surface, could impact carbon sequestration to the deep ocean due to incorporation into zooplankton faeces, moults and carcasses, and may impact zooplankton health. Findings will therefore aid the modelling of plastic pathways around the Antarctic and sub-Antarctic islands.

Following my PhD, I embarked on a postdoctoral position under the wider UKRI funded Future Leader Fellowship programme ‘CalcUlating the strength of the Plastic pump In counteracting the Deep export of Oceanic carbon’.  This multi-national project approaches plastic from a novel biogeochemical angle. In short, the project explores how plastic pollution may impact the blue carbon pathway. Zooplankton play a critical role in this activity through the sinking of their faeces, moults and carcasses and through their vertical movement along the water column. Plastic pollution may threaten this carbon pathway by lowering the sinking velocity of zooplankton faeces, moults and carcasses. Ultimately, this could reduce the capability of the ocean to regulate atmospheric CO2 emissions. This is particularly important since the oceans absorb approximately 30% of atmospheric CO2, helping to mitigate the effects of climate change.

Through further fieldwork and laboratory work with the British Antarctic Survey, the main objectives of my postdoctoral work are to (1) explore the role of zooplankton in promoting the transport of oceanic plastics (2) determine how plastic may interfere with the ability of zooplankton to store carbon in the deep ocean. The cutting-edge multidisciplinary approach includes an extensive field-based research programme, in which novel floating and moored ocean platforms are used and in situ experiments conducted. The extensive dataset created will again inform ecological models.