The partners of the DECODE project consortium, representing various sectors such as knowledge institutions, private enterprises, are committed to integrating their diverse expertise to promote the implementation of an innovative biomonitoring strategy based on eNA. It is widely acknowledged that addressing the problem of biodiversity loss requires a fast and standardized technique. While eDNA shows promise, its practical application is hindered primarily by uncertainties surrounding the fate and transport of genetic material within ecosystems [Barnes & Turner, 2016]. The following key questions arise: How do the hydraulic regimes within marine and river ecosystems influence the spread of eDNA/eRNA? How are eDNA-based biodiversity assessments influenced by legacy eNA in aquatic ecosystems?

Knowledge about the transport and the age of the genetic material in the water ecosystem will be instrumental for having reliable biodiversity assessment with eDNA. By leveraging this knowledge, we will design a sampling protocol that takes into account the hydrodynamics of the aquatic system (flow velocity, water depth, mixing and stratification).

The project has a duration of 16 months, during which we have planned two main research activities.
Activity 1: eDNA sampling protocol in static water conditions for assessing multiple-species.(duration 5 months)
Activity 2 - eDNA sampling protocol for in-river biomonitoring regarding rare species. (duration 16 months)

The DECODE project promotes the application of an innovative biomonitoring technique that addresses the limitations of traditional methods. Through experimental activities, the DECODE project evaluates multi-species biodiversity assessments using eDNA and investigates the dynamics of genetic material spreading in controlled environments. It also conducts the first eDNA campaign focused on genetic material spreading in lowland rivers. Indeed, until now the majority of riverine monitoring activities with eDNA were performed in alpine regions.
The project's innovation lies in the development of methodologies that enable the estimation of species distributions at finer geographic scales. Efforts are being made to ensure an accurate assessment of the distance traveled by sampled eDNA. This involves combining knowledge of hydrodynamics, such as flow transport velocity, with information about the age of the sampled eDNA (time traveled).
Therefore, the DECODE project's primary impact lies in advancing our understanding of eDNA trace dynamics, which offers valuable insights into ecosystem status. This knowledge serves as a powerful tool in efforts to reverse the degradation of riverine biodiversity. Moreover, the project indirectly contributes to expanding knowledge in the field of micron-sized particle physics, which is relevant for investigating phenomena such as microplastic pollution and larval fish migration patterns.
Furthermore, the project's multidisciplinary approach paves the way for other research advancements. Analytical advancements are made through the design of species- and taxon-specific primer sets, and through the optimization of lab protocols by adopting chloroform-free extraction methods. The latter represents a significant step forward in efficiently processing and analysis of genetic samples and enables them to be conducted on liquid handling stations.

1: Primer sets designed for (a) North Sea taxa or taxon groups, and (b) riverine biodiversity in the Meuse.
2: Protocol for analyzing aquatic DNA including chloroform-free extraction methods that can be run on liquid handling stations.
3: Report outlining the sampling protocol for pelagic and benthic species.
4: Publication of findings on RNA/DNA analysis for age estimation and metabarcoding for biodiversity assessment.
5: Open dataset containing (a) all experimental campaign data in the North Sea tank, (b) all field campaign data in the Meuse, (c) a map showcasing genetic material occurrences in the Meuse.
6: Protocol for age estimation of genetic material in riverine systems.

Most products will be made publicly available on the 4TU.ResearchData repository.

the research activity will be advertised to the general public through the TKI website. Announcements
will primarily be made on the TUD webpage and the announcement sections of other partner websites.
To engage the scientific community, we plan to participate in one conference and disseminate the campaign results through a research paper and a conference proceeding.
Furthermore, we will actively engage the general public and interested members of the scientific community in
biodiversity conservation through social media. We will create a Twitter thread featuring pictures of the research activity and publish them with a frequency of three tweets per month.
The consortium will hold two general meetings during the project, and a final appointment will be scheduled at the end of the project to present the outcome of the DECODE activity to stakeholders in the Netherlands associated with biodiversity monitoring.

The consortium will conclude a cooperation agreement that meets the requirements of the scheme.