Comparison of prokaryote communities extracted from sediments stored at -70C and -80C.
Long-term storage of DNA, RNA, samples for DNA and RNA extractions is usually done in ultra-low temperature freezers using the standard temperature of -80°C. While this standard was based on the maximum capacity of early generation ultra-low temperature freezers, this paradigm is challenged and initiatives support a switch to -70°C to save up to 26% of energy, reduce heat production, and increase the life expectancy of the freezers. The question arising from these initiatives regards the safety of the samples. Especially in complex biological samples, such as sediments, changes in long-term storage temperature have not been studied in detail. Here, we show that the concentration of extracted nucleic acids and nucleic acids in tissue or cells stored at both temperatures does not differ significantly from each other. In addition, we show that prokaryote community composition remains stable in sediment samples stored at -70°C. Consequently, we recommend storing this kind of samples for nucleic acid work at -70°C to reduce energy consumption and support more sustainable lab practices.