IMIS - Marine Onderzoeksgroepen

The importance of understanding and valuing biodiversity and ecosystem health is becoming ever more important. Global anthropogenic change, new economic activities and increased maritime mobility can have a broad impact on biodiversity. Consequently, evaluating the impact of economic activities on biodiversity and ecosystems is increasingly recognized by the corporate world. To this end, the use of environmental DNA (eDNA) is offering valuable information on spatio-temporal patterns of species distribution and is gaining traction due to its non-invasive nature, cost effectiveness and scalability. eDNA surveys are increasingly used in aquatic ecosystems for policy and management decisions. Yet, limitations and challenges remain, particularly in complex marine environments like the North Sea. eDNA techniques are indirect observation methods and may fall short due to potential false positive or negative species detections. Such uncertainties may lead to incorrect management and policy decisions that negatively impact (delay or disable) economic activities. This then lowers the trust of stakeholders in applying eDNA-based techniques and leads to traditional methods remaining a requirement for many potential applications. 
The eDNA-OPTIMA project addresses current challenges in eDNA based biodiversity monitoring by mitigating the fundamental issues that lead to false positive and false negative species detections. It aims specifically to tackle and better characterize key processes of transport, resuspension and degradation that influences the distribution, detection, and persistence of eDNA in a given sample. To do so, we first investigate the underlying mechanisms by combining field and laboratory experimental and observational approaches in the North Sea. To identify potential false positive observations from allochthonous eDNA, we will assess how far eDNA is transported by water currents. This involves conducting field experiments utilizing artificially-introduced eDNA sources, such as cages containing oysters, to quantify transport distances. The project leverages bioinformatics and hydrodynamic modeling to further refine eDNA monitoring capabilities. By developing methods to analyze eDNA fragmentation patterns, we then can estimate eDNA degradation and infer the time it has spent in the environment and how much distance it may have covered in this time. Ultimately, we aim to create a comprehensive model that predicts eDNA dispersal trajectories and origin based on degradation rates and hydrodynamic models. 
A key objective of the project is to establish robust protocols for eDNA collection and data interpretation. Here, we focus on minimizing the risk of false positives and negatives by rigorously evaluating sampling techniques and replication strategies to mitigate contamination. Furthermore, we aim to optimize eDNA monitoring protocols specifically for macrobenthos communities within the North Sea. There, macrobenthos is a critical part of marine biodiversity that has been notoriously difficult to assess using eDNA. A crucial aspect involves comparing eDNA obtained from the water column and sediment to determine the most efficient method for species detection. Simultaneously, we will evaluate the potential effect of eDNA resuspension from the sediment that may lead to false positive detections. Ultimately, this effort will culminate in the development of comprehensive guidelines for reliable eDNA data collection and reporting. 
As current eDNA collection methods at sea are still often labor-intensive, we will develop technologies and test procedures to collect eDNA samples with automated sampling devices on fixed structures and uncrewed surface vessels. Automation of eDNA sampling holds great promise (especially for blue economy companies) but requires the establishment and testing of best practices to safeguard the necessary quality standards. These advancements will pave the way for the utilization of eDNA as a reliable and efficient tool for monitoring biodiversity and ecosystem health within the North Sea and in other marine environments.