team of microbiologists at the University of Amsterdam (UvA) are reporting that many toxin-producing algal varieties are even more adept at handling changing climatic conditions than scientists previously thought. This finding is reported in the journal PNAS this week, and has implications for clean drinking water, swimming safety and freshwater ecosystems.
The research team, led by Professor of Aquatic Microbiology Jef Huisman, studied Microcystis, a type of blue-green algae, or cyanobacteria, that proliferate in lakes and reservoirs in summer. They analyzed the genetic composition of cyanobacteria, observing Microcystis in both the lab and Kennemer lake, under CO2-rich and poor conditions.
“Before this, the adaptive potential of these harmful cyanobacteria in response to increasing CO2 concentrations had never been studied systematically, even though this can help us predict how algal blooms will develop in future,” said Xing Ji, a PhD researcher on the team.
In both the lab and the lake, cyanobacteria’s genetic makeup changed in response to increasing CO2 concentrations. “It’s a textbook example of natural selection,” says lead author Giovanni Sandrini. “Cyanobacteria absorb CO2 during photosynthesis to produce their biomass, and we observed that the strain best equipped to absorb dissolved CO2 eventually gains the upper hand.”
Some Microcystis strains have a slow but efficient carbon uptake system that enables them to squeeze out the last bit of CO2 from the water even at very low concentrations. Those strains become dominant in low CO2 conditions. By contrast, other strains have a fast uptake system that allows them to take up dissolved CO2 at very high rates when in high concentrations. “We discovered that these high-speed strains enjoy a major selective advantage in CO2-rich water,” Dr. Sandrini said. “Given the rising atmospheric CO2 values, these strains are poised to thrive.”
This study was conducted by the University of Amsterdam and funded with a TOP grant from the Netherlands Organisation for Scientific Research (NWO).