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Bacteria study: Selfish polysaccharide degradation is the focus of research
Research at the UNI Bremen reveals how bacteria in Croatian lakes break down organic matter and influence the environment.
Bacteria study: Selfish polysaccharide degradation is the focus of research
A new study involving microbiologist Greta Reintjes has examined the role of bacteria in breaking down organic matter in Croatia's freshwater lakes. The results will be published in the specialist journalCell Reportspublished and documented for the first time the mechanism of “selfish polysaccharide degradation” in freshwater ecosystems. Bacteria carry out this particular degradation by internally digesting large polysaccharide molecules, which could have a significant impact on nutrient availability in these waters.
The scientists analyzed two lakes, the oligotrophic Kozjak Lake and the mesotrophic Crniševo Lake. Lake Kozjak has low nutrient and algae concentrations and freezes over in winter, while Lake Crniševo has higher nutrient levels and is in a Mediterranean climate. Water samples were taken in the spring and summer months of 2022 and winter 2023 and the bacterial composition was analyzed in the different seasons.
Selfish bacteria and seasonal variations
In the study, researchers showed that selfish bacteria were present in both lakes, but the intensity of their activity varied depending on the season. In particular, greater bacterial diversity was found in Lake Crniševo and greater selfish nutrient uptake occurred than in Lake Kozjak. Furthermore, selfish activity in Lake Crniševo increased after the phytoplankton bloom in summer, while in Lake Kozjak this activity peaked in nutrient-poor winter.
The most common polysaccharide processed through this selfish degradation was pullulan, a sugar produced by fungi. This specialized way of breaking down the bacteria could have a significant impact on the food web in the respective lakes.
Impact of climate change and future research
The study's results also raise questions about the future impacts of climate change on nutrient dynamics in freshwater lakes. The research team plans to use genomic methods to identify relevant genes and enzymes to study selfish bacteria in additional ecosystems. This work is supported by funding from the DAAD, the FEMS Research and Training Grant, the DFG and the Croatian Science Foundation.
Additionally, Phase 1 of a research program to investigate the influence of warming on biological indices of water quality in Switzerland is mentioned. To this end, data from various monitoring programs between 2010 and 2019 were used to analyze the effects of temperature changes on local communities and the depth of measurement of water quality. The results showed that water quality testing will remain reliable in the coming years as long as there is no extreme warming. Further details can be found in the article inEcological indicatorsto find here.
This comprehensive study shows the central importance of bacteria to ecological nutrient cycling in freshwater ecosystems and illuminates the possible effects of climate change on these complex biological processes.