Interactive effects of nitrate pollution and heatwaves on the aquatic macrophytes

Abstract:Eutrophication from anthropogenic pollution such as nitrogen is a global concern, further intensified by climate change-induced heatwaves. While the individual effects of nitrate and temperature on macrophytes are known, their interactive impacts remain unclear. To understand these complex stressor dynamics, we investigated the interactive effects of nitrate (5, 50, and 200 mg/L) and heatwave (no, short-moderate, and long-intense), on submerged macrophytes (Myriophyllum spicatum) and the floating-leaved macrophytes (Potamogeton natans) using a 3 x 3 factorial design. Results showed nitrate promoted floating species' growth but inhibited submerged species. Long and intense heatwave accelerated both macrophytes' growth under elevated nitrate, whereas nitrate limitation restricted the growth. This underscores the importance of adequate nutrients for optimal development during warming events. Photosynthetic efficiency declined with increasing nitrate, particularly during heatwaves, suggesting that warming may exacerbate nitrate's negative effect. Antioxidant response varied with heatwave, highlighting the complex stressor interactions. Additionally, high nitrate and long heatwave significantly increase N:P and C:P ratio, indicating phosphorus limitation, which may affect macrophytes' quality as food and disrupt ecological balance. Overall, the effects of nitrate on macrophytes are species-specific and influenced by environmental conditions such as temperature, emphasizing the importance of understanding how nutrient and extreme climate events interact in aquatic ecosystems.

Publication year:2025

Keywords:Biology, Aquatic sciences

Accessibility:Closed