Bacteria in Lake Mendota evolve with changing seasons

According to IFLScience, bacteria in Lake Mendota, Wisconsin, evolve in an endless cycle, responding to the changing seasons. Research by scientists from the University of Texas at Austin has demonstrated that these bacteria adapt throughout the year, evolving in response to seasonal environmental changes.

During winter, the lake is covered with ice, while in summer, it becomes populated by algae. These seasonal changes compel bacteria to adapt to low water temperatures in winter and harsh conditions in summer. Scientists conducted their research over nearly 20 years, analyzing 471 samples of microorganisms collected during this period. The project underscores that genetic variability is common and frequent, with cyclical seasonal patterns observed in 80% of the samples.

Many species of bacteria appear to evolve backward, reverting to the genetic state from thousands of generations ago. Since microbes have short life spans, living only a few days, scientists can analyze thousands of generations of evolution within a single year.

"I was surprised that such a large portion of the bacterial community was undergoing this type of change," said Robin Rohwer, a researcher from the University of Texas at Austin.

In 2012, the lake experienced unusual weather conditions. An extremely hot and dry summer led to earlier than usual ice melting and reduced water inflow, resulting in a decrease in algae. These changes significantly impacted bacterial life processes, particularly nitrogen metabolism. Such phenomena have proven crucial for understanding the evolutionary processes of microorganisms in this ecosystem.

Research published in "Nature Microbiology" emphasizes that ecology and evolution are closely interconnected. Understanding these processes can benefit research on microorganisms and their roles in ecosystems.