Phytoplankton growth and potential cyanotoxin production differ in response to nitrogen and phosphorus amendments in late summer communities from Kabetogama Lake (Minnesota, United States).

Key Points

• The study investigates how nitrogen and phosphorus amendments affect phytoplankton growth and cyanotoxin production in Kabetogama Lake.
• Conducted experiments in late summer communities of Kabetogama Lake in 2021 and 2022.
• Assessed phytoplankton growth and cyanotoxin production under different nutrient treatments compared to control groups.
• Evaluated the correlation between heterocyte abundance and gene expression related to microcystin.
• Phytoplankton growth was significantly higher with nutrient treatments than in controls in 2021, but not consistently in 2022.
• A positive correlation was found between heterocyte abundance and MC gene expression, indicating nitrogen fixation's role in toxin production.
• Variation in taxonomic composition within phytoplankton groups contributed to inconsistent community responses.