Results from experiments to measure the effect of nutrients on phytoplankton growth and potential toxin production in Kabetogama Lake (Minnesota, USA) during September 2021 and 2022

We performed short-term lab bioassays with nutrient enrichment on field-collected, naturally occurring phytoplankton communities. Naturally-occurring phytoplankton communities were collected from Kabetogama Lake (Minnesota, USA), which is a large lake located within Voyageurs National Park. Two experiments were performed in 2021 and two in 2022. Phytoplankton were raised in the lab under controlled light and temperature conditions, but were provided with amendments of nitrogen (either reduced or oxidized), phosphorus or a combination of all three. We measured the growth (in units of chlorophyll a and biovolume) and upregulation of cyanotoxin production for communities after two days of incubation in the lab.