Mahardja, B.; Bashevkin, S. M.; Pien, C.; Nelson, M.; Davis, B. E.; Hartman, R. Escape from the Heat: Thermal Stratification in a Well-Mixed Estuary and Implications for Fish Species Facing a Changing Climate. Hydrobiologia, 2022, 849, 2895–2918. https://doi.org/10.1007/s10750-022-04886-w.
Mahardja, B.; Bashevkin, S. M.; Pien, C.; Nelson, M.; Davis, B. E.; Hartman, R. Escape from the Heat: Thermal Stratification in a Well-Mixed Estuary and Implications for Fish Species Facing a Changing Climate. Hydrobiologia, 2022, 849, 2895–2918. https://doi.org/10.1007/s10750-022-04886-w.
Mahardja, B.; Bashevkin, S. M.; Pien, C.; Nelson, M.; Davis, B. E.; Hartman, R. Escape from the Heat: Thermal Stratification in a Well-Mixed Estuary and Implications for Fish Species Facing a Changing Climate. Hydrobiologia, 2022, 849, 2895–2918. https://doi.org/10.1007/s10750-022-04886-w.
Mahardja, B.; Bashevkin, S. M.; Pien, C.; Nelson, M.; Davis, B. E.; Hartman, R. Escape from the Heat: Thermal Stratification in a Well-Mixed Estuary and Implications for Fish Species Facing a Changing Climate. Hydrobiologia, 2022, 849, 2895–2918. https://doi.org/10.1007/s10750-022-04886-w.
Abstract
Climate change may cause organisms to seek thermal refuge from rising temperatures, either by shifting their ranges or seeking microrefugia within their existing ranges. We evaluate the potential for thermal stratification to provide refuge for two fish species in the San Francisco Estuary (SFE): Chinook Salmon (Oncorhynchus tshawytscha) and Delta Smelt (Hypomesus transpacificus). We compiled water temperature data from multiple monitoring programs to evaluate spatial, daily, hourly, intra-annual, and inter-annual trends in stratification using generalized additive models. We used our data and models to predict the locations and periods of time that the bottom of the water column could function as thermal refuge for salmon and smelt. Periods in which the bottom was cooler than surface primarily occurred during the peak of summer and during the afternoons, with more prominent stratification during warmer years. Although the SFE is often exceedingly warm for fish species and well-mixed overall, we identified potential for thermal refugia in a long and deep terminal channel for Delta Smelt, and in the periods bordering summer for Chinook Salmon. Thermal stratification may increase as the climate warms, and pockets of cooler water at depth, though limited, may become more important for at-risk fishes in the future.
Keywords
water temperature; stratification; endangered fish species; thermal stress; refugia; temperature refuge; delta smelt; chinook salmon; San Francisco Estuary
Subject
Biology and Life Sciences, Ecology, Evolution, Behavior and Systematics
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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