Photosynthesis Big Hole River in southwestern Montana

Big Hole River in southwestern Montana. USGSN scientists and their university colleagues have shown that photosynthesis by aquatic plants causes large diel (daily) cycles in pH, dissolved oxygen concentrations, and the isotopes of oxygen and carbon. In addition, the aquatic plants are thought to cause large changes in streamflow as oxygen production during photosynthesis stiffens the plants and thereby retards downstream flow during the day.