Speaker: Jasmine Krause, PhD candidate, Water Resources, Department of Biological and Ecological Engineering, Oregon State University

Seminar: From Synthesis to Sensors: Understanding Oxygen Regimes in Headwater Streams

Abstract
Dissolved oxygen (DO) is a fundamental indicator of aquatic ecosystem health and an integrative signal of physical, biological, and biogeochemical processes in streams. However, much of the empirical and conceptual foundation for oxygen dynamics is derived from studies of perennial streams and relies on assumptions of spatial homogeneity and in-channel dominance that may not hold in headwater networks. This talk begins with a synthesis of empirical studies quantifying surface and subsurface oxygen exchanges across streams and rivers, highlighting persistent methodological biases, limited representation of the fluxes that generate whole-stream signals, and the underrepresentation of intermittent headwaters. Building on this synthesis, I present high-frequency sensor observations and targeted field experiments from a spatially intermittent headwater stream in the H.J. Andrews Experimental Forest, Oregon, USA, to examine how DO dynamics reorganize across hydrologic states. Finally, I link observed DO patterns to underlying oxygen fluxes, demonstrating how different processes become dominant under certain flow conditions. Together, this work underscores the need for empirical investigation in intermittent headwaters, where strong heterogeneity challenges existing assumptions about oxygen dynamics.

Bio
Jasmine Krause is a PhD student in Water Resources Science at Oregon State University. Her expertise lies at the intersection of aquatic ecology and hydrology, integrating field-based sensor measurements and modeling to improve understanding of stream processes. Her Ph.D. research focuses on dissolved oxygen dynamics in headwater streams, particularly the roles of intermittency and subsurface exchange in shaping oxygen variability.