Cascading effects of micro- and nano-plastics on lipid quality and transfer through freshwater planktonic ecosystems

Despite growing global concern about the occurrence of small plastic particles (nano- and micro-plastics) in the world's seas, rivers and lakes, there has been limited research into understanding any adverse effects on living organisms. Investigations of the consequences for aquatic food webs are even rarer.

Recent, unique research at Cardiff University has shown how widespread algae are affected by some microplastics - specifically through changes in the composition of their lipids. These molecules are important in the structure and functioning of all cell membranes, including the plasma membrane, chloroplast and mitochondrial membranes, as well as in the waxes and steryl esters that provide structure to the extracellular layer and cell wall. The synthesis of essential fatty acids (FAs) also appears to be disrupted.

These discoveries not only reveal a fundamental mechanism through which plastic could affect algae, but also suggests that plastic pollution could disrupt whole freshwater food webs from the bottom upwards. Zooplankton, for example, depend on high-quality algae for their food and growth, in turn providing important biomass for predators.

This cutting-edge PhD will explore such effects further, investigating i) how different types and sizes of plastic (nano- to micro) affect the lipid composition of different algae and ii) assessing the potential for cascading effects between freshwater algae and zooplankton using microcosms, mesocosms and actual field conditions.