Welcome to the inaugural edition of our EuroMarine Researchers in the Spotlight series, where we engage in captivating conversations with prominent researchers within our network.

Today, we're privileged to speak with Mark John Costello, an ecologist who has navigated the waters of marine science with an unwavering passion and a determined spirit. His expertise spans biogeography, Marine Protected Areas, and the profound impacts of climate change on biodiversity, including the intriguing world of aquaculture-environment interactions.


Mark's journey in marine science is marked by innovation. He's a trailblazer in the field of 'ocean biodiversity informatics', recognized for his instrumental role in establishing the World Register of Marine Species and Ocean Biodiversity Information System databases. These comprehensive databases house a staggering 240,000 marine species and a whopping 80 million distribution records, unveiling new vistas of understanding about marine life. His work has unveiled the hidden count of unnamed species, the dynamics of biodiversity along the equator, and the profound effects of climate change on marine life migration. His insights have reshaped our perception of marine ecosystems and are a cornerstone in shaping strategies for global marine biodiversity protection.

With a mentor's heart, Mark has nurtured the growth of over 70 graduate students. His legacy is reflected in over 280 peer-reviewed publications, with a cumulative citation count of 19,000 and a notable H-index of 69. Mark's impact extends across international horizons. He has left his mark on organizations like the Intergovernmental Panel on Climate Change, where he played the lead role in the 6th Assessment Report’s Cross Cutting Chapter on Biodiversity Hotspots. His leadership in the Group on Earth Observations Marine Biodiversity Observation Network and various other global initiatives underscores his commitment to a sustainable future.

Mark’s journey commenced in Ireland, where his fascination with wildlife led him to study in Galway, earning his BSc Honors. His quest for knowledge took him to diverse corners of the world, from Marine Biological Association in Plymouth, England, to Scottish Office Aberdeen, Napier University in Edinburgh, and Trinity College Dublin. He even established his own environmental consulting company, EcoServe. Now a professor at Nord University in Arctic Norway and a Visiting Professor at the Ocean University of China, Qingdao, Mark’s influence spans the globe.

EuroMarine: What initially sparked your interest in marine research, and how did you embark on this career path?

Well, my interest in marine research only began in Galway when I was a student, but I was always interested in nature, right from a very, very early age, as far as I can remember. I was always amazed just watching insects and other wildlife. Just watching their lives and what they were doing and were their lives like ours – which they are really – they just go about it in a different way. When I got the opportunity to go to university, I wanted to study zoology. I talked about veterinary science, but I didn’t get enough points. And anyway, after I learned that veterinarians have to stick their arms up the bottoms of cows and horses, I thought that’s not very pleasant work. So I thought biology was much more interesting and more open because you could do anything. In Galway, they specialized in marine biology, so we did a lot of marine biology field trips and it was really interesting. Even though I started my first project, which was like a nine-month, BSc honours project, was on freshwater ecology, because that was my supervisor's interest at the time. But then I went on to do a PhD in marine science. I thought I was very lucky to get paid to do something that I enjoyed doing in a subject that was interesting to me.

EuroMarine: What are your primary research interests and areas of focus within marine sciences? (biogeography, Marine Protected Areas, and the effects of climate change on biodiversity)

So when I was in Galway, one of my lecturers talked about the Theory of Island Biogeography. One time we had this in our honours year, these short courses, and I was just amazed that somebody had figured out a mathematical way of explaining the geographic and richness patterns of life on Earth. When we look at nature, everything seems so chaotic and so much is going on, but actually, there are some patterns to it. So that's kind of got me interested. During my PhD, I did some work on biogeography. It's important to nature conservation and now very much in climate change - it has applications. I find even today, now it seems to be somewhat a forgotten subject in marine science. A lot of marine scientists think it's just geography and they don't understand the theories behind it. So I spent quite a bit of time teaching courses and explaining to referees of my papers the differences and the patterns of the theories in the subject. So, then I went into ecology, I guess, as part of biogeography. I did work in aquaculture and, climate change and invasive species, but they're all kind of connected to this biogeographic background.

EuroMarine: Could you highlight any major findings or breakthroughs that you have achieved in your research? How did they happen?

Yeah, so they probably only happened in recent years. One was that we started creating some online databases, just because we thought they were useful. We created a database listing all species in Europe so we could organize the taxonomic names and which were synonyms and which were not. And then we did a world list. And this was just to be something useful. Then I got asked as part of the census we would like to lead the Ocean Biogeographic Information System, which we set up over about 8 years. And now it's hosted by UNESCO IOC very well. They do a great job. Then we started analyzing the data in these big databases because we could never have looked at global patterns before by one person, since it would take so much time to collect all the data. One of my students was doing a master's on razor clams, she looked at the latitudinal gradient of species richness and she discovered that it wasn't peaking at the equator. There was a decrease at the equator, and we thought, oh, that must be something unusual to do with razor clams. But the journal that was accepting the paper, wouldn't accept that she called this bimodal, you know, with a dip at the equator and two peaks at mid-latitudes. So then we looked at all the literature and we found that it was always bimodal in all the papers, but nobody ever talked about it before because people just assumed that their data was wrong. Or they just drew a line across it. They just didn't think about it because everybody says, you know, richness peaks at the equator, but it doesn't. And it hasn't actually since the last ice age. And now it's getting deeper due to climate change. Then one of my students had a great paper two years ago showing that there are fewer and fewer species at the equator and more and more mid-latitudes due to climate change. That is because temperature drives this pattern. Which then means that, well, most marine species can be anywhere they want. They can move with the changing temperatures. So maybe biogeography is not so important in some ways for marine species compared to terrestrial ones.

So that was the first one. And then arising from that, we looked at what point the number of species decrease. Well, it decreases above 20 degrees centigrade. And this was a big surprise because we think, well, you think more species would be in the tropics in the high 20s. But in fact, at 20 degrees, we get all the temperate climate species and all the tropical species together. And it turns out – we just had a paper accepted two days ago, I am very excited – on the 20-degree centigrade effect. I think this will be the biggest finding of my career, because it turns out that this happens right across freshwater, terrestrial, air-breathing, water-breathing and it's got an underlying, physio biochemical reason. Energetics are most efficient at 20 degrees centigrade in cells. This is sort of like a general pattern that 20 degrees turns out to be this pivotal kind of temperature for life on Earth. Even in the fossil record, there's been a paper showing that you get more extinctions when the average temperature is above 20 degrees. We still need to work out the details of how it works, but I think this is exciting. The paper was accepted two days ago in the journal Frontiers in Biogeography, which is the journal of the International Biogeographical Society, IBS.

EuroMarine: What are the priority areas for marine research that could have a significant impact on policy development and sustainable marine management?

Yeah, so I've actually been talking to some of the policy people, in Europe and nationally in the last couple of years because we're now leading this project, Marine Protected Areas Europe. They keep asking me all these really simple questions that are very hard to answer. They would have wanted our results two 2 years ago because they're already having to manage and create Marine Protected Areas in the absence of enough data. One of the questions was, well if we don't have enough data, what are the most fragile areas and what should we stop doing? But in some ways the answer is obvious. You stop bottom trawling, which destroys habitats. The King of England apparently tried to ban bottom trawling in the 19th century more than a hundred years ago and his law wasn't obeyed. And, now we're a hundred years later and people think there's no alternative for bottom trawling. Well, of course, there are alternative ways to catch fish that are less harmful to the environment.

I also think there's a communication issue with the wider society. We need greater public awareness of what is really going on. A lot of protected areas are not protected at all because the fisheries policy doesn't align with the nature conservation policy. This is a problem in Europe, Canada, Norway and other countries, where you have different government agencies, not synchronizing their management objectives. In a way, one of the problems is science communicating this knowledge effectively and not over-exaggerating it; because if you dramatize it, the policymakers think you're just exaggerating the issue. Scientists need to make it convincing and make it sound like common sense - actually, a lot of these things are common sense. It's kind of odd that people come up with all sorts of crazy ideas.

People in fishing communities, and indigenous communities have long known that if your fish population is declining, then you stop fishing and let it recover. So it's really strange when you hear some fishery scientists saying that marine protected areas don't benefit fisheries. There are all sorts of strange arguments going on that limit action.

I think we need faster publication of field data like the weather forecast; we can get weather data within hours. Why can't we get biodiversity data at least within days or weeks? Well, actually we can. There’s a new website called birdweather.com where in real-time, you can see what birds are occurring all over Europe and North America from automatic, little microphones that are recording their sounds. And citizen science data gets published in the GBIF every month - it's research grade.

And yet scientist’s data publication is very slow. This is one of the things, within EuroMarine, we're going to look at with the MBON Europe; try and accelerate getting data published and stop this sort of putting embargoes on data until we get our papers out, which might never happen. I have papers going back decades that I haven't published. I think all scientists build up this backlog of work they should publish, but never get around to.

EuroMarine: How can EuroMarine engage with policymakers and stakeholders to ensure that scientific findings are effectively communicated and utilized in decision-making processes?

I've only recently gotten more involved with EuroMarine since I came back to Europe, but before EuroMarine, we had other organizations and projects. And at that time, I think we were doing the wrong thing. We were campaigning a bit like a trade union. We said we needed more research funding for this and that. This is not very convincing to policymakers. Everybody wants money from them, every organization in society, and instead we should have a much more positive relationship with the policymakers and government agencies. We should be showing how we can help them because we're a network and how actually institutions are already doing a lot of research that maybe the policy makers don't know about.

And that's one thing in MBON Europe. We're just getting the MoU agreements signed now - we have 14 founding members now. Because institutions are already monitoring biodiversity, but we don't exactly know which ones and what they're doing. This is what we're trying to do in EuroMarine to bring this together and show policymakers that the scientific community is doing a lot without any extra or special funding because we all want the same thing. We want good data to give good advice. And I think this will have positive feedback with the policymakers, the European Commission and other agencies because they'll see why they shouldn’t be giving money to some new project that wants to do everything all over again. Why not give the money to people who are already doing it and just add some value to their work and greater recognition?

EuroMarine: What are some of the main challenges or obstacles you have encountered in your research, and how have you addressed them?

I was actually talking to people in India a few weeks ago, who have a hugely growing society, and they're all trying to get jobs. Well, in the 1980s in Ireland, when I did my PhD, it was the same, there were no jobs. And when I did my Bachelor's, there were no jobs, I think only one-tenth of our class got a job in our field. But now there are many jobs actually. The biggest challenge early in my career was actually getting a job and getting a post doc. I only got one offer. And in the time I had, a teaching position, only temporarily.

Then I set up a consulting company with my research group because we had lots of external funding. Then I happened to marry a Canadian and got another job in Canada for a while. So, I think once we have a job that's the most important thing. A position in academia is especially privileged because we can do whatever research we like, usually at the university. And that is why we should do whatever research we think is important, not just what other people want us to do. A lot of my best papers were just, review papers or thought papers from collaboration with other people. My most highly cited paper is with over 100 authors from the World Register of Marine Species, where we reviewed the database content, and tried to infer what that meant for marine biodiversity. I think that's over 1000 citations now. Before that, there was a simple method paper, which took me one day to write.

So, yeah, we don't actually always need a lot of research funding. We just need time. That means work-life balance and having good health and all these things as well.

EuroMarine: What are your future research plans and directions? Are there any specific goals or projects you are currently working on or planning to pursue?

For the last few weeks, I've been pretty much full-time writing a new research proposal that is to try to advance Marine Protected Area management by doing more automated or semi-automated monitoring in protected areas. This could be applied anywhere. I try to shorten this gap between data collection and publication. And then produce that data, produce meaningful indicators, not like some scientific index that nobody can understand. If there are very big fish in a place then it must be reasonably natural because they haven't been fished out. And this is actually easy to measure if you can find enough measurements and you don't have to kill fish to do it; you could use video cameras, with cetaceans we can use sound, with birds, we can use sound and we could probably start using video cameras. We have two live streaming in the fjord here now, and they're not that expensive to put in anymore. It's a few thousand euros for the cables and they're plugged into a scuba diving center. We see all sorts of cool things on the videos every now and again. It's like those apps we use for security cameras on our houses. It can send a message to your phone anytime there's movement. So every time a fish swims past the camera, I get a message, but I have to turn it off because during the summertime, the fish are going past nonstop. So, I think we can use these new technologies to get better data and data that are relevant to society and science at the same time.

Q: NORD University has recently joined the Network and you have been a very active member of its Steering Committee. How has this involvement supported your research so far? What new services or initiatives could EuroMarine develop to support the needs of the marine scientific community?

I never said what MBON Europe stands for. It's the Marine Biodiversity Observation Network and it's part of a global effort biodiversity observations, which has been going on for about 15 years - I was on as a chair of their Steering Committee for about 10 years. And eventually, I realized we were a bit too academic. We're all talking about how to monitor and what variables to use and all these kinds of things, but we didn't actually know who was doing it and what was happening, which is what we're trying to do within EuroMarine. I think that that could be one central thing EuroMarine could do. I mean, it's only biology as well while EuroMarine should be more than biology. Maybe we should broaden it to include other types of environmental variables as well and be more holistic. We could connect it to industry monitoring in the future. Many fish farms monitor data, maybe there's a way in the future that all this data can be coordinated and made available so that we know what's going on in the marine environment in a more cost-effective way. EuroMarine: Are there any individuals or experiences that have particularly inspired or influenced your research journey?

That's a hard question. Well, I mentioned the professor at my first university, I guess that he was the one to inspire me for biogeography. I've had many good friends. I got married, and we're over 30 years married. She's a scientist as well; she has been very supportive.

I've admired quite a lot of people in freshwater science. For instance Noel Hynes. He's dead now. Some years ago, he wrote a book on Freshwater Ecology. I think Daniel Pauly, who is one of the most highly cited scientists is a very eloquent speaker and he writes lots of good papers and he carved his own path through his career. He didn't follow the traditional routes. He often was outspoken against conventional fisheries management and government organizations, and he got in trouble. But he stuck to doing good science, and he's shown that in the long term, when you're right, and the science is correct, it is worth it.

There are many people I collaborate with; many of my PhD students - together we made these discoveries I talked about. I don't want to single any out or I might get in trouble.

EuroMarine: What advice would you give to early career scientists?

We actually had a workshop on this at the University of Auckland. And then later on, I polled about 30 colleagues around the world and got all their experiences, and what advice would they give to their younger selves. There is a link to it on the Oceans of Biodiversity website that I have at the University of Auckland.

I think when it comes to research, a colleague of mine said (he was in medical school), you only got a master's or PhD for writing. So, writing is the most important thing and most students leave writing too late. They should start writing on day one, and then you start writing and reading and writing and reading, and then you do the lab work or fieldwork or any other data analysis work as well. But all is about communication and in science it is largely happening through writing, and the students that do well usually write and publish early. That's actually, I think somebody proved that they did an analysis of researchers' careers, and the only significant variable was how early in their career they published their first paper. That was the best guarantee of long-term success.