Sarah Cadieux

Freshwater ecosystems play pivotal roles as sentinels, integrators, and regulators of climate change. My research takes an interdisciplinary approach to understanding biogeochemical cycling within freshwater systems by combining limnology, aquatic chemistry, isotope biogeochemistry, sedimentology, and geomicrobiology. While my current work focuses primarily on urban freshwater environments, it also extends to Arctic systems and other regions undergoing rapid environmental change. Using these approaches, I investigate two broad themes: (1) the sources, transport, and fate of micropollutants and anthropogenic materials in freshwater environments, and (2) greenhouse gas dynamics associated with natural and human-driven disturbance events. Each area of research incorporates community engagement and outreach while addressing fundamental questions about how human activities reshape aquatic and geologic systems.

A central focus of my work is understanding how anthropogenic materials are transported, transformed, and ultimately preserved within environmental systems. In freshwater ecosystems, I study microplastics and other micropollutants as tracers of human influence on the landscape. Although water often appears clear, it contains a complex mixture of dissolved and particulate materials that remain largely invisible to the naked eye. In water samples collected throughout Troy, New York, microplastics are found in all samples, highlighting the ubiquity of these materials in everyday life. Beyond documenting contamination, I use microplastics as a model system to investigate the physical, biological, and geochemical processes that govern particle movement through aquatic environments.

This interest in anthropogenic materials extends beyond the water column and into the geologic record. As part of this work, I am investigating how plastics and other human-derived materials become incorporated into sediments and emerging rock formations, creating stratigraphic markers of the Anthropocene. By studying the pathways through which synthetic materials are preserved, I seek to understand how contemporary human activities may be recorded in future geologic archives.

Another focus of my research examines greenhouse gas cycling in freshwater ecosystems. Lakes and reservoirs are important sites of methane production and emission, yet the mechanisms controlling methane dynamics remain incompletely understood, particularly during periods of environmental disturbance. Through studies of methane production, oxidation, and transport, I investigate how microbial communities, biogeochemical processes, and changing environmental conditions regulate greenhouse gases in aquatic ecosystems. This work links ecosystem-scale processes occurring within lakes to broader questions of climate feedbacks and global carbon cycling.

Across these research areas, visualization serves as both a scientific and educational tool. Many of the processes I study, from microscopic plastic particles to methane cycling and the incorporation of anthropogenic materials into sediments, are difficult to observe directly. By combining analytical measurements with visual approaches and community science, I seek to make these otherwise invisible environmental processes accessible while advancing our understanding of how human activities are becoming embedded within aquatic ecosystems and the geologic record.