Allochthonous nutrients and carbon are recognized as dominant controls on biogeochemistry of low-order streams. In some systems, potamodromous fish may provide a complementary source of material as they deliver lake-derived materials to spawning streams. This study examines nutrient and carbon inputs from terrestrial ecosystems and migratory fishes to streams in undeveloped watersheds in northern Michigan, USA. We compared watershed and riparian area, slope, and landcover to nutrient concentrations at 26 sites, as well as whole-stream metabolism at 5 sites. Despite low levels of agricultural land use (0–3%), agriculture had the largest influence on stream chemistry as indicated by higher dissolved organic carbon (DOC), ammonium, silica, [...]
