Are biodegradable plastics really better for the environment - impacts on the structure and functioning of ecological communities

Each year millions of tonnes of plastic are mismanaged, leading to their accumulation in the environment as litter. Almost half of this plastic debris is composed of single-use items including food wrappers, plastic bottles, and plastic bags, leading to calls for increased environmental regulation around the conventional plastics sector. Recently, there has been a drive to replace conventional, fossil fuel-based plastics with biodegradable ones; little is known, however, about their ecological impacts.

Biodegradable plastics could be slow to deteriorate or even detrimental for ecosystems under natural environmental conditions, necessitating the field experiments in this project comparing the impacts of different plastics on the structure and functioning of ecological communities. Research methodology

A series of in situ field experiments will compare the impacts of biodegradable plastic, conventional plastic, and paper bags on biodiversity and biogeochemical cycling. In situ manipulations will be conducted in the River Wensum in Norfolk, the Colne Estuary in Essex, and agricultural soils at the National Institute of Agricultural Botany (NIAB) in Soham, Cambridgeshire.

Experimental plots (1 m2) will be marked out, with plastic and paper treatments secured to the substrate using metal pins. Degradation rates of plastic/paper will be monitored during the experiment. Invertebrate assemblages will be characterised at the beginning and end of the experiment using microscopy.

Carbon and oxygen fluxes will be measured using gas-tight chambers, with nutrient fluxes quantified along depth profiles from cores. Research findings will be used to help develop policy to reach ecological good status (e.g. under UN Sustainable Development Goals no.14, UK Marine Strategy indicator D10 Marine litter).