Journal Article Research Support, Non-U.S. Gov't mesocosm 27YLU75U4W Humic Substances Phosphorus Review anthropogenic stressors biodiversity biotic mechanisms climate change climate variability deep-mixing ecosystem function ecosystem multifunctionality ecosystem productivity ecosystem services extreme events global change gross primary production harmful algal blooms lake browning large-scale lake survey long-term monitoring multiple stressors nutrient gradient physicochemical mechanisms respiration stratified lakes