PhD Studentship: How do anthropogenic contaminants alter zooplankton-mediated biogeochemistry in a changing ocean

Zooplankton are central to marine food webs and play a critical role in ocean biogeochemistry through nutrient recycling, carbon export and trophic transfer. However, marine ecosystems are increasingly exposed to complex mixtures of anthropogenic contaminants, including plastics, plastic alternatives and metals, alongside global change stressors such as ocean warming, altered salinity and nutrient enrichment. Understanding how these interacting pressures affect zooplankton and the ecosystem functions they support is a major challenge for predicting and managing ocean change. This PhD will investigate how environmentally relevant contaminant mixtures influence the physiology, behaviour and ecological functioning of key zooplankton species, and how these responses scale up to affect marine biogeochemical cycling. The Doctoral Researcher will combine field observations from the Western English Channel with laboratory experiments exposing copepods and other planktonic organisms to contaminants individually and in combination with changing environmental conditions. Measurements may include survival, growth, reproduction, respiration, feeding behaviour, oxidative stress biomarkers and transcriptomic responses. Key research questions include: How do contaminant mixtures and climate-related stressors interact to affect zooplankton health and performance? Do contaminants alter grazing, nutrient regeneration and carbon export processes mediated by zooplankton? How do zooplankton influence the transport, transformation and trophic transfer of contaminants through marine ecosystems? Which contaminant-stressor combinations pose the greatest risk to ecosystem functioning and biogeochemical resilience? The questions are intentionally broad to support student-led development of novel research directions. Fieldwork will be conducted at PML's long-term monitoring site L4 aboard RV Plymouth Quest, complemented by experiments in PML's ultraclean facilities and University of Exeter laboratories. Through collaboration between PML and University of Exeter, the student will undertake research visits, access specialist FlowCam and plankton culture facilities, and receive interdisciplinary training spanning marine ecology, ecotoxicology and biogeochemistry.