Award: OCE-1747722

Microorganisms in coastal environments must have the ability to respond to changes in salinity, and understanding the microbial response to salinity is critical due to the connection between variability in coastal salinity and climate change. This project examined changes in microbial metabolism as a function of salinity. The project used two strains of bacteria within the SAR11 group, with a specific focus on SAR11 strains that have made the transition away from growth strictly limited to a seawater environment. The bacterial cells were allowed to grow in seawater or brackish water to examine how the resulting differences in salinity altered the organic compounds measured inside the cells. The accumulation of organic compounds varied across the two strains examined, which suggests that even across closely-related bacterial strains the response to salinity differences is not consistent. The project also determined that increased numbers of bacterial cells were needed to obtain measurable levels of organic compounds from this group of bacteria. This raises as yet unanswered questions as to why metabolites are present in low concentrations in the freshwater SAR11 strains. Beyond the realm of research, the project also contributed to the broader community. A graduate student was partially supported on this project while he worked on developing bioinformatics tools to efficiently merge metabolomics data with genomics-based datasets. With the increased availability of data from different ‘omics streams, the graduate student’s work is widely relevant. Furthermore, the data on the composition and concentrations of the chemical compounds is being made available through online data repositories and the data are available for anyone to mine and apply to their own research questions. Last Modified: 04/18/2023 Submitted by: Elizabeth B Kujawinski