How does dissolved oxygen vary across riverscapes and what does it mean for fish and conservation?
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As we consider the effects of climate change on riverine ecosystems, water temperature often plays a starring role. We are increasingly able to characterize temperature through space and time and understand its physiological effects on fishes. Historically, empirical data on dissolved oxygen have been far more limited due to the cost and difficulty of monitoring. However, the development of low-cost sensors has increased the coverage and temporal depth of dissolved oxygen data across river networks. Dissolved oxygen is more complex to understand and predict than temperature because it is controlled by and sensitive to a suite of abiotic and biotic factors at different spatial and temporal scales. Understanding the patterning and consequences of dissolved oxygen variation is critical for climate change adaptation, because oxygen is fundamentally important to fish and interacts with temperature to determine the physiological tolerances of fish and their responses to warming. Current standards and management approaches to meet standards for dissolved oxygen often rely on static thresholds applied uniformly over large spatial scales. Here we share field studies and statistical analyses that highlight key uncertainties associated with dissolved oxygen: (1) how is it patterned across riverscapes (2) how does diel variation in dissolved oxygen and synchrony with water temperature mediate physiological effects and the distribution of fish, and (3) how can we develop and implement quantitative standards that are robust to these complexities and uncertainties?
The views expressed in this abstract are those of the author and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency or Oregon Department of Environmental Quality