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Community Structure Has Greater Effect On Water Column Ammonium Cycling Than Nutrients And Temperature In Shallow Lake Mesocosms, Shannon Marie Collins

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Harmful algal blooms (HABs) impact lakes worldwide and are caused by excess nitrogen (N) and phosphorus (P) loading from watersheds. Climate warming and nutrient loading effects on N cycling were examined in shallow lake mesocosms in Denmark. N loading to some mesocosms ceased in June 2018 and resumed in June 2019. Ammonium (NH4+) uptake, regeneration, and nitrification and nitrate uptake rates were evaluated. High nutrient, ambient temperature mesocosms exhibited the highest NH4+ cycling rates. Before resumption of N loading in high nutrient mesocosms, NH4+ regeneration supported 46 % of potential microbial NH4+ demand, versus 24 % with N loading. Nutrient …