Limited Adaptability Makes Freshwater Bacteria Vulnerable to Climate Change
Published:12 Jul.2024 Source:University of Zurich
Freshwater bacteria with small genomes frequently undergo prolonged periods of adaptive stagnation. Based on genomic analyses of samples from Lake Zurich and other European lakes, researchers at the University of Zurich uncovered specific evolutionary strategies that shape these bacteria's lifestyles. Understanding the evolutionary dynamics of aquatic microbial communities is key to safeguarding ecosystem services.
Bacteria adapt to their environments by utilizing specialized proteins, which can be secreted into the surrounding medium or bound to their cell membranes. These proteins play crucial roles in nutrient uptake, interbacterial communication, and the detection of and response to environmental stimuli. The adaptability of bacteria typically relies on the genetic diversity within the genes encoding these proteins. The researchers, however, now show that in abundant freshwater bacteria with reduced genome sizes, there is surprisingly little variation in these genes, indicating a phase of adaptive stagnation. These bacteria may therefore face challenges in adapting to changing environmental conditions.
Their proteomes have already attained an optimal state through the course of evolution, where further major changes are neither advantageous nor necessary for the organisms to survive and adapt to their current niches. This inherent inflexibility limits the ability of these organisms to explore new genetic variation and effectively adapt to dynamic environmental conditions.