Publication Raw Data - Sample preservation solution increases nucleic acid yield and environmental RNA quality in sediments across an estuarine salinity gradient

Environmental nucleic acid-based assessments are powerful tools for understanding microbial ecology, and environmental degradation in aquatic environments. This approach is particularly useful in guiding restoration in estuaries, some of the most degraded ecosystems in the world. The recent popularity of this approach has been accompanied by a parallel increase in the diversity of applied methods. While standardising methods across the field is required, there is also a particular need to select methods that account for physicochemical gradients, maximising yield and quality of nucleic acids sampled across sites within a study area. A consistent approach to intra-study nucleic acid sampling also ensures accurate comparison between those sites. This study evaluates environmental nucleic acid (eNA) sampling methods across salinity gradients in aquatic ecosystems, focusing on the impact of preservation techniques on environmental DNA (eDNA) and environmental RNA (eRNA) yield and quality. Fieldwork was conducted at three sites within the Coorong estuary system in South Australia, representing freshwater, marine, and hypersaline conditions. Snap freezing and LifeGuard preservation solutions treatments were applied to understand their effects on nucleic acid yields and eRNA integrity. Snap freezing enhances eDNA yield in freshwater sediments but negatively impacts eRNA integrity in marine and hypersaline conditions. Conversely, LifeGuard preservation consistently improves both eDNA and eRNA recovery across all salinity levels, which makes it a good candidate for preserving eNA molecules across environmental gradients. The study underscores the necessity of tailoring sample preservation methods to specific environmental conditions for accurate eNA-based microbial community assessments in coastal ecosystems. These findings contribute to the development of robust eNA sampling protocols for benthic communities under varying salinity conditions.