Understanding what is happening beneath the surface of the ocean is operationally challenging. Marine environments are complex, dynamic, and often difficult to access, yet reliable biodiversity data is increasingly required to support environmental assessment, monitoring programmes, and long-term project planning.
Environmental DNA (eDNA) has become a valuable tool in marine biodiversity monitoring, providing a way to detect biological presence without relying on direct observation or physical capture. For those working in challenging marine environments, eDNA offers an additional source of biological data that can complement established monitoring approaches.
Rather than replacing existing survey methods, eDNA monitoring is most effective when integrated into a broader monitoring system.
What is eDNA monitoring?
Environmental DNA monitoring involves collecting water samples and analysing them for genetic material released by organisms into the surrounding environment. This material originates from naturally occurring biological traces such as skin cells, mucus, scales, or waste.
Following sample collection, laboratory analysis is used to identify genetic signatures associated with different species. The results indicate which organisms are, or have recently been, present in a given area, without requiring visual confirmation or physical interaction.
In marine environments, eDNA monitoring is particularly relevant where visibility is limited, access is constrained, or repeated surveys are required across depth or distance.
How eDNA monitoring works in marine environments
While the basic principles of eDNA monitoring are well established, implementation in marine settings requires careful consideration.
A typical marine eDNA monitoring workflow includes:
● Water sampling at defined locations and depths
● Sample handling and preservation to reduce contamination and degradation
● Laboratory analysis to identify genetic material
● Interpretation of results alongside environmental and operational data
Marine conditions introduce additional variables. Currents, water movement, temperature, and salinity all influence how eDNA disperses and how long it remains detectable. As a result, sampling strategy and deployment design are critical.
From an operational perspective, repeatability, consistency, and integration with other monitoring data are often more important than single-point results.
Why eDNA is useful in applied marine monitoring
When used appropriately, eDNA monitoring can support marine biodiversity programmes by complementing traditional survey methods.
It can help identify species that are difficult to detect visually, including low-abundance or cryptic organisms. It is also well-suited to deep, remote, or low-visibility environments in which conventional surveys are constrained by deployment time, weather windows, or access limitations.
Because eDNA sampling does not require physical interaction with organisms or habitats, it can be applied in sensitive environments where minimising disturbance is a consideration.
This makes eDNA a practical addition to monitoring programmes that already rely on imaging, sensors, or remote platforms.
Limitations and practical considerations
eDNA monitoring effectiveness must be viewed in the context of the deployment environment and project related factors. The presence of genetic material does not always indicate the presence of living organisms at the precise sampling location, as DNA can persist in the environment and be transported by water movement.
Results are influenced by sampling design, contamination control, environmental conditions, and analytical methods. These factors must be considered at the programme design stage to ensure data is interpreted appropriately.
In applied monitoring contexts, understanding these limitations is essential to use eDNA data responsibly and effectively.
Integrating eDNA into wider monitoring systems
In operational marine monitoring, eDNA delivers the most value when integrated with other technologies rather than deployed in isolation.
Optical imaging, environmental sensors, acoustic systems, and physical surveys each provide different data types. eDNA adds a biological dimension that can strengthen overall understanding when aligned with these datasets.
This system-level approach supports more robust monitoring programmes, enabling data to be cross-referenced, validated, and contextualised over time.
Relevance across marine and energy sectors
Although eDNA monitoring is widely associated with ocean science and research programmes, the same principles apply across other marine and energy sectors.
In offshore energy, biodiversity monitoring supports environmental assessment and ongoing operational responsibility. In aquaculture, genetic monitoring can contribute to ecosystem awareness when used alongside imaging and environmental monitoring systems.
Across all sectors, the shared requirement is reliable data collection in harsh and remote marine environments, using monitoring solutions that can be deployed, repeated, and integrated with confidence.
Designing effective eDNA monitoring programmes
Effective eDNA monitoring begins with clearly defined objectives and a realistic understanding of operational conditions. Decisions around sampling frequency, deployment method, and system integration all influence the usefulness of the data collected.
When applied thoughtfully, eDNA monitoring provides a practical way to strengthen marine biodiversity programmes and support informed decision-making in complex marine environments.