… NAU [Northern Arizona University] and University of California Berkeley scientists working along the region’s Eel River have discovered a micro-scale nutrient factory that keeps rivers healthy and allows salmon to thrive. The scientists’ new study in Proceedings of the National Academy of Sciences (PNAS) reveals how a partnership between algae and bacteria works like nature’s clean-nitrogen machine, turning nitrogen from the air into food that fuels river ecosystems without fertilizers or pollution. The hidden nutrient factory boosts populations of aquatic insects, which young salmon rely on for growth and survival.