Abstract
Fine particles (1 - 1000 µm) in streams are often conglomerations of mineral and organic particles, as well as microflora and fauna such as bacteria cells. Potentially harmful fine particles include both contaminant microorganisms (including fecal indicator bacteria and human enteric bacteria and viruses) and microplastics. There are numerous concerns with river transport of fine particles over long distances downstream of non-point and point sources. Fine particles comprise the majority of the total sediment (and organic matter and nutrient) flux and pose risks for ecological and human health. During baseflow conditions, hyporheic exchange flow processes between surface water and the streambed, transport fine particles into streambed sediments. Fine particles immobilize and accumulate within streambed sediments during baseflow conditions by gravitational settling, attachment to in-stream structures such as submerged macrophytes, and hyporheic exchange and filtration within underlying sediments. However, dynamic flow conditions alter the transport processes of fine particles, notably by remobilizing them during high flow events. The extent of remobilization is dependent on both, the increase in magnitude of the flow and the number of fine particles previously immobilized within the streambed sediments. This seminar will present recent experimental and modeling results on fine particles including microplastics and E. coli transport dynamics in streams.
Short Biography
Dr Jen Drummond is a Marie Skłodowska-Curie (MSCA) Individual Fellow at the University of Birmingham, UK. Her research focuses on the underlying mechanisms that control water, microbial, and fine particle (e.g., particulate organic matter or microplastic) transport and retention within freshwater systems to improve stream ecosystem functioning and assess microbial risk within agricultural and urban systems. She completed her PhD at Northwestern University in 2015 with an extended research visit to NIWA-Hamilton, New Zealand. Since then, she has worked as a post-doctoral fellow (Fulbright Scholar, US NSF Earth Sciences Postdoctoral Fellow) based mainly at the Centre for Advanced Studies of Blanes (CEAB-CSIC) in Blanes, Spain. She moved to the University of Birmingham in 2019 as a Royal Society Newton International Fellow to pioneer the development and field validation of a model for predicting the persistence of microplastics and associated pathogens in streams.
