Water is a major ecological requirement for life on Earth. It covers more than 70% of the planet?s surface, albeit only approximately 2% of it is occupied by freshwater. Freshwater ecosystems are regarded as biodiversity hotspots, providing a habitat to approximately 10% of all described metazoan species. Globally, freshwater bodies are being depleted, the related ecosystems are being degraded, and freshwater biodiversity is declining at many scales. Therefore, long-term freshwater biodiversity monitoring is not only needed to measure the changes in biodiversity but the monitoring must also be expanded to include more species and areas.
Biodiversity assessments using molecular identification of organisms through high-throughput sequencing techniques have been a game changer in ecosystem monitoring, providing increased taxonomic resolution, more objective identifications, potential cost reductions, and reduced processing times. The use of DNA metabarcoding of bulk samples and environmental DNA (eDNA) is now widespread but is not yet universally implemented in national monitoring programs. While bulk sample metabarcoding involves extraction of DNA from organisms in a sample, eDNA analysis involves obtaining DNA directly from environmental samples, which can include microorganisms, meiofauna-size taxa and macrofauna traces such as larval stages, skin and hair cells, gametes, faeces and free DNA bound to particles.
In Norway, freshwater biomonitoring in compliance with the EU Water Framework Directive (WFD) is conducted on several administrative levels, including national monitoring programs for running water, small and large lakes. These programs typically focus on a fraction of the actual biodiversity present in the monitored habitats. DNA metabarcoding of both bulk samples and eDNA samples are relevant tools for expanded future freshwater biomonitoring in Norway.
The aim of this PhD project is (1) to develop assessment protocols based on DNA metabarcoding and eDNA of benthic invertebrates, microcrustaceans and fish that can be used as standard biomonitoring tools to assess the ecological condition of lakes, and (2) to evaluate the effect of improved taxonomic resolution from molecular techniques on determining the ecological status of lakes, both by broadening the number of taxa analyzed and by identifying more taxa to species level.