This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from USDA’s rich science and research portfolio.
Recent warming of terrestrial climates combined with decreased stream flows has raised concerns about possible increases in stream temperatures in the Pacific continental United States. Loss of cold, clean water in the region has major implications for human use and for sensitive coldwater fishes, such as salmon and trout. In a joint project, the U.S. Geological Survey (USGS), U.S. Forest Service’s Pacific Northwest Research (PNW) Station, and Oregon State University (OSU) researchers assessed the climate effects on cold water in low and high human-influenced sites using long-term stream temperature data from the USGS and the Forest Service.
Trends in stream temperatures at these sites were locally variable and often did not conform to simple expectations based on hypothesized climate effects. Analysis of 1987-2009 stream data revealed fewer warming trends and surprisingly more cooling trends in stream temperatures. To understand historical and predict future climate effects, the authors suggest the need for more extensive sensor networks to track stream temperatures over broader geographic areas and for longer time periods. The study was recently published in the Geophysical Research Letters by the American Geophysical Union.
The study co-leads are OSU’s Ivan Arismendi and PNW Research Station’s Sherri Johnson. To read the report, click here.