Guiding ocean policy with microbial insights: Tackling pollution through innovative science

Marine microorganisms are pivotal to oceanic ecosystems and biogeochemical processes but are often overlooked in global change studies and policy development. Understanding the complex structure and function of microbial communities is crucial for accurately predicting the impacts of pollution. Unlike traditional studies that focus on taxonomic structure and genetic potential, our metaproteomics studies enable to examine protein regulation, thus linking genotype to phenotype and deepening our understanding of microbial involvement in biogeochemical cycles and their responses to multiple stressors. This presentation focuses on two critical environmental threats in two case studies: oil spills and plastic pollution, and how new molecular approaches have enhanced our understanding of the vital roles of microorganisms in environmental mitigation and their resilience to multiple stressors.  In the first case study, we assess the impact of the chemical dispersant Corexit® EC9500A during the Deepwater Horizon oil spill, the largest in U.S. history, with about 4.9 million barrels of crude oil released into the Gulf of Mexico. Despite the role of Corexit in enhancing oil dispersion by reducing surface tension, the interaction of Corexit with microbial communities remains controversial. Our metaproteomics approach provides the first molecular evidence that dispersants can intensify stress responses in marine bacteria more significantly than the oil itself within 24 hours. This insight helps refine oil spill models and identify key proteins for potential bioremediation, which could reduce reliance on chemical dispersants and lower cleanup costs.  The second case study explores plastic pollution, an escalating issue with profound ecological and socioeconomic impacts. Marine microorganisms rapidly colonise plastic surfaces, significantly affecting the fate and risks of these pollutants in various geographical locations. Our research sheds light on microbial dynamics on marine plastic surfaces, noting that different climates influence the activity of key microorganisms including hydrocarbonoclastic taxa. By integrating both published and unpublished data, I will present the latest advancements in understanding the functional regulation within the so-called marine plastisphere. I will present detailed guidelines for our metaproteomics workflows, from cell lysis to the creation of protein search databases and automated data analysis.  The outcomes of these case studies, widely covered in hundreds of UK media outlets, demonstrate the power of metaproteomics in uncovering microbial regulation and adaptation, offering new approaches to tackle pollution and multiple stressors. Our objective is to enhance marine microbial ecology using cutting-edge metaproteomic tools, which are crucial for a deeper functional understanding in the context of climate and environmental changes. This will ultimately guide the development of sustainable strategies to effectively mitigate pollution challenges.