This dataset records Cladophora and associated benthic algae, collectively Cladophora community or submerged aquatic vegetation (SAV), biomass collected during the growing season of 2018 at stations located along the U.S. shoreline of Lakes Michigan, Huron, Erie, and Ontario. It also records a variety of supporting data collected at Cladophora measurement stations. These supporting data include: - seasonal time series of light, currents, wave action, temperature, specific conductivity, turbidity, pH, phycocyanin, chlorophyll, and dissolved oxygen from moored sensors at a subset of stations; - measurements of Secchi disk depth and water chemistry; - water column profiles of temperature, specific conductivity, turbidity, pH, phycocyanin, chlorophyll, and dissolved oxygen; - diver observations of SAV, dreissenid mussel, round goby abundance and substrate properties; - measurements of dreissenid mussel abundance and size class distribution coincident with SAV biomass; - nutrient content of SAV, dreissenid mussels, and sediments; - and information about sampling locations and operations. This is a revised version of data release; all changes are described in the ReleaseHistory_Cladophora2018_v2.txt. First posted: April 30, 2020 Revised, v1-1: September 30, 2020 Revised, v2: June 2023