Streams and Seasons: A Year in the Life of East Fork Creek

In the heart of Tennessee, a small stream named East Fork Creek has been under close watch. Scientists have been keeping tabs on it for a whole year, from May 2022 to May 2023. They were curious about how the stream's 'breathing' changes with the seasons and time of day. They set up month-long camps and a special four-day event in July 2022 to gather data. This stream's health is like a living diary, recording changes in temperature, water clarity, and chemicals like calcium, magnesium, and even seawater salts. Dissolved oxygen (DO) levels in the stream dance back and forth. During the day, it's like the stream is holding its breath, with high DO. But at night, it's as if the stream exhales, showing low DO. This breath-like pattern is strongest in summer. Scientists used a smart method called the Bayesian model to calculate how much life in the stream produces oxygen (Gross Primary Productivity) and how much it uses up (Ecosystem Respiration).GPP, the oxygen production, has a clear pattern. It's at its peak in July and hits a low in winter, following the light regime of the day. ER, the oxygen use, doesn't vary much except for a slight bump in fall, possibly due to extra organic stuff from land. The stream's main driver for creating oxygen is light, while the main driver for using it up is temperature. Most of the time, the East Fork Creek has a heterotrophic regime, meaning it uses more oxygen than it produces, releasing CO2 into the air. If there's plenty of carbon, warmer temperatures could lead to more CO2 emissions and low oxygen events (hypoxia) in the future.