Five Minutes With Marcus Donnelly


17 Sep 2025

5MW Marcus

Knowledge of the undersea environment is paramount to keeping our people and assets safe. Navies across the globe need robust Underwater Situational Awareness - the ability to perceive, comprehend, and anticipate environmental conditions and potential threats beneath the surface to ensure they can continue to operate safely and effectively. We spoke with our Environmental Data Science Technical Authority, Marcus Donnelly to learn more about the role he plays in this.  

Thank you for joining us, Marcus, what does your role entail?  

My role is focused on underwater acoustics, the ocean environment, and their effects on sonar systems. I provide input to and technical oversight of projects and software products, input to bid submissions and liaise with external companies and universities. 

I also do a lot of technical work, tasks like numerical modelling, data analysis, and software development. I work in the Python programming language which, with its extensive ecosystem of libraries, is the worldwide standard development platform for Data Science. I was an early adopter of Python at SEA, starting to use it for research work around ten years ago, and have helped others to develop their skills over the years. 

We sometimes work with universities in collaborative project teams and have sponsored university PhD research. Presenting and publishing at scientific conferences and in journals also helps with maintaining our reputation for technical work. 

What drew you into environmental modelling? 

I grew up in Zambia, surrounded by amazing landscapes and wildlife, visiting sites like Victoria Falls, so I’ve always been interested in the natural environment. At University in Bath, I studied underwater acoustics, which also gave me knowledge of oceanography. Over the years, I’ve built that up to a specialist role covering acoustics and ocean science, combined with software development. 

What are you most proud of in your time at SEA? 

I’ve been here for 25 years. When I started, SEA had just won the first ever maritime research task put out by the MoD, which I was asked to lead. It was a challenging step for someone relatively junior. A key output was the Ambient Noise Prediction System, which is still being used by the Royal Navy to this day, with our continuous support and upgrades over time. 

That task has been a launchpad for many things at SEA, and built credibility for the company, allowing us to recruit more people and win further contracts in underwater research. 

How do you see environmental modelling develop over the years? 

Interest in ocean sciences is only increasing. Not least because of climate change, more organisations need an understanding of the physical, chemical, and biological aspect of the world’s oceans. 

I think the rapid expansion of the domain will continue, with more environmental sensors, including in-situ sensors and satellites. More observation data, combined with increasingly high-resolution numerical modelling and data bandwidth, means it’ll stay a very interesting area to be working in. 

What skills would you recommend for someone trying to get into Environmental Data Science? 

A degree in the sciences, physics in my case, is a necessary starting point. Skills needed include data analysis, numerical modelling, software development, and the ability to extract information from large datasets. Visualising all of this in innovative ways, doing analysis and inferring knowledge from lots of data is fundamental. Report writing, presentation and communication are also important. 

Other than that, you do need to have curiosity for the work, look out for developments in the area and adapt them. 

Thank you, Marcus. 

Find out about what we do in the Undersea Battlespace.