TY - RPRT TI - Periphyton biomass and community compositions as indicators of water quality in the Lower Grand River hydrologic unit, Missouri and Iowa, 2011–18 AU - Heather M. Krempa PY - 2021 DO - 10.3133/sir20215012 UR - https://pubs.usgs.gov/publication/sir20215012 ID - sir20215012 ER -