Interactive Effects of Temperature, Nitrogen, and Zooplankton on Growth and Protein and Carbohydrate Content of Cyanobacteria from Western Lake Erie

Abstract

Harmful algal blooms (HABs) in freshwater ecosystems, especially of cyanobacterial species, are becoming more frequent and expanding geographically, including in Lake Erie in North America. HABs are the result of complex and synergistic environmental factors, though N or P eutrophication is a leading cause. With global mean temperatures expected to increase an additional 2˚C -5˚C by 2100, cyanobacterial blooms are predicted to increase even more, given their typically-high temperature optimum for growth. We investigated how increases in temperature and nitrogen, singly or in combination, affect the growth, food quality, and herbivory of Lake Erie cyanobacteria. Algal community samples collected from Lake Erie, and isolated non-N-fixing (Microcystis aeruginosa) and N-fixing (Anabaena flos-aquae) cyanobacterial species, were cultured at 20˚C, 25˚C, or 30˚C, and at 5, 50, 150, or 250 μM N, and then analyzed for growth and (for isolates) content of total protein and non-structural carbohydrates (NSC). Temperature and N both affected algal growth, and there were temperature × N interactions, which were sometimes affected by presence/absence of zooplankton. For example, cyanobacteria (but not green algae) growth increased with both temperature and N, especially from 25˚C to 30˚C, but N and herbivore presence increased cyanobacterial growth primarily only at 30˚C. In general, temperature and N had little consistent effect on NSC, but increasing temperature and N tended to increase protein content in Microcystis and Anabaena (temperature effects mostly at higher N levels). In Anabaena, increases in N did not increase growth or protein at 20˚C or 25˚C, but did increase both at 30˚C, indicating that N fixation * Corresponding author. D. Bista et al.1140 is damaged at high temperatures and that high NO3 can overcome this damage. These results indicate that future global warming and continued eutrophication will increase cyanobacterial growth, as well influence algal herbivory and competition between N-fixing and non-N-fixing cyanobacteria.

Comparative analysis of the gut microbiota in bighead carp under different culture patterns

“…According to our investigation of the pond water plankton community structure, we found the Cyanophyta and Chlorophyta phylas dominated the phytoplankton, while Rotifers and Protozoa were abundant in the zooplankton, and shows a clear seasonal change. Enhanced sunshine, higher nutritional salts and fish excretion all contributed to increasing phytoplankton density in the early stages of culture (Bista et al, 2014). As fish grow, the amount of bait increases, residual bait and extra excretion continue to breakdown, resulting in eutrophication, which is exacerbated by rising temperatures and other factors (Wu et al, 2017).…”

Variation of Local Wind Fields under the Background of Climate Change and Its Impact on Algal Blooms in Lake Taihu, China

“…While algae proliferate and blooms form as a result of various environmental factors [15][16][17][18], accumulating evidence has indicated that climate conditions may be the main limiting factor of algal bloom formation when a lake maintains a high level of eutrophication [5,19,20]. Under favorable climate conditions, algal cells can proliferate rapidly and form algal blooms in eutrophic lakes [2].…”