Revealing population demographics with environmental RNA.

The analyses of environmental DNA (eDNA) and environmental RNA (eRNA) released by organisms into their surrounding environment (water, soil and air) have emerged as powerful tools for monitoring biodiversity. While eDNA has been widely adopted for the non-invasive detection of species and characterization of community composition, the utilization of eRNA is still in its infancy. Due to its functional nature, eRNA holds intriguing potential for biodiversity monitoring offering new avenues of research beyond species detection.

Environmental transcriptomics under heat stress: Can environmental RNA reveal changes in gene expression of aquatic organisms?

To safeguard biodiversity in a changing climate, taxonomic information about species turnover and insights into the health of organisms are required. Environmental DNA approaches are increasingly used for species identification, but cannot provide functional insights. Transcriptomic methods reveal the physiological states of macroorganisms, but are currently species-specific and require tissue sampling or animal sacrifice, making community-wide assessments challenging.

Environmental RNA degrades more rapidly than environmental DNA across a broad range of pH conditions.

Although the use and development of molecular biomonitoring tools based on environmental nucleic acids (eDNA and eRNA; collectively known as eNAs) have gained broad interest for the quantification of biodiversity in natural ecosystems, studies investigating the impact of site-specific physicochemical parameters on eNA-based detection methods (particularly eRNA) remain scarce. Here, we used a controlled laboratory microcosm experiment to comparatively assess the environmental degradation of eDNA and eRNA across an acid-base gradient following complete removal of the progenitor organism (Daphnia pulex). Using water samples collected over a 30-day period, eDNA and eRNA copy numbers were quantified using a droplet digital PCR (ddPCR) assay targeting the mitochondrial cytochrome c oxidase subunit I (COI) gene of D.