Do you know corals breathe? And what about the fact that they get “stressed”? Do you know that you can bring a whole lab underwater and measuring all of this?

As part of the series “Draw My Science”, I interviewed marine biologist Walter Dellisanti, Ph.D. candidate at City University of Hong Kong and coral expert. And I made illustrations inspired by our chat.

Walter, originally from Italy, started by studying micro-organisms and how human footprints, causing the increase of CO2 into the water, affect them. He now lives in Hong Kong where he studies brain corals metabolism and how they respond to external stressors.

We talked about his science, about the importance of science communication, and about the best seabeds he ever visited. You can listen to the entire interview on Youtube, or read the selected extract below.

Without any further ado, let’s dive in (pun intended)!

The Interview

Hi Walter — Tell us briefly what you are studying right now.

I got a Master Degree in Marine Biology — I have always been interested in marine ecosystems, focusing on organisms’ physiology. I started with micro-organisms, but now I am focusing on something a little bit bigger.

I am currently a Ph.D. candidate at City University of Hong Kong. I am studying coral metabolism. I am interested in what corals are doing underwater and their physiological status. Basically how they can respond to natural fluctuation in the water.

You mentioned you started by studying micro-organisms. Can you tell us more?

I was studying how micro-organisms, like plankton, respond to ocean acidification. Ocean acidification is a process caused by the uptake of atmospheric CO2 by seawater, and through a series of chemical reaction molecules of hydrogen get dispersed in the water lowering its pH — making the water more acid. This is a natural process, but due to human activities, we see a further increase in the acidity of seawater.

Is coral metabolism affected by this acidification process?

Of course. Corals are affected by multiple stressors. I want to know what corals do under certain conditions. But instead of putting them under stress, I go underwater to measure some specific biological processes. Then I can correlate the change of these biological processes with environmental fluctuations.

Hong Kong is a special area for corals. In fact, corals typically prefer tropical environment, while Hong Kong is a subtropical one, making it already an extreme condition for corals.

Do the corals around Hong Kong differ from tropical corals? Or are the same corals under higher stress?

In normal conditions, corals can survive natural fluctuations. Tropical corals prefer warm water, more salty water, higher water currents that can transport more nutrients. In Hong Kong, we have summer and winter seasons — during the summer, the temperature is higher and it gets very rainy; during the winter, it is colder but dry. Because of these conditions, there are different species of coral in Hong Kong than in the tropics – and these types of corals have a higher resistance to natural fluctuations.

The real question is: how do they adapt to these natural fluctuations?

How many species of corals do you study?

I am focusing on a single species, a reef coral with boulder shape — its common name is brain coral. Maybe, later on, I will compare it to a second one. But Hong Kong has around 150 different species of corals, and only a few people know about it!

You mentioned that specifically, you are studying coral metabolism – But what is coral metabolism, and how do you study it?

I use an instrument that I can bring diving and place it directly on the coral surface. And the instrument measures oxygen, pH, and temperature — effectively measuring the respiration, photosynthesis, and calcification of the corals, directly underwater!

The revolutionary idea of this study is to bring the lab in the water, instead of disrupting and collecting corals from the sea to the lab. It is challenging: for example, we a limited amount of time that we can spend in the water. But it is worthy, as we can see exactly what the corals are doing in their natural environment while avoiding damage to the corals themselves. In the lab, we can study more corals and more conditions, but it is all artificial.

We also collect information on the water around the coral and its conditions. If I see that my corals are under stress, I can go back and check what could have caused it.

A lab under the sea

We cannot bring everyone underwater, that’s why we need more science communication to reach the ones that cannot physically be there.

I noticed you referred to the corals as “my corals” – This shows a lot of passion! What’s your relationship with the corals?

We have selected colonies. And we always go back to the same corals. I go to visit “my corals” once a month. These corals can adapt very fast to changes in conditions. I did some preliminary studies in the lab and timed that the response to environmental change is in the order of 30-60 minutes. But we do not know the response to slower long term changes, like seasons. That’s why I go back every month and visit them.

We all agree that corals are beautiful. But why should people care about this research? What’s the important takeaway of this study?

One of the problems that we have with marine, environmental or ecological studies is that it is difficult to reach people. It is very difficult for scientists to explain our science and for people to get in touch with science.

A key takeaway is that we need to protect corals. Protecting corals does not mean just protecting one species, but protecting the entire ecosystem. With healthy corals, we have more fishes and marine organisms, such as crabs, that can use them as nursery areas, for reproduction or just for living. And more fishes, especially edible ones, is a benefit for communities living on the sea. We need to discuss what the corals are doing under stress and most importantly trying to understand where the stress comes from.

But we also want to send the message that protecting the marine environment means giving the opportunity to future generations to enjoy these ecosystems in all the possible ways, from fishing to diving.

You said that it is difficult to reach people about marine biology, and corals. You were the first one to show interest in this “Draw your science” project. Maybe these two things are connected. Would you like to comment on this?

I have always worked in research, and I feel that it is difficult for myself explaining what I am doing to people working in another field of study. Even just explaining my science to my family is not easy. I know it is difficult to bring awareness to other people about the marine ecosystem. When I saw your tweet I thought it was a very cool project – I love the drawing part of it because it can really reach all the people, from kids to adults.

Since you mentioned that from your experience not many people know about marine biology and the types of study you do, I wonder: how did you end up as a marine biologist?

I started diving almost 20 years ago when I was still a kid. I am from Barletta, a city on the seaside in the south-east of Italy. I have got my first diving license when I was 12 – and it was really for just playing. I got the opportunity to try diving, and really my first impression to breathe underwater was really like discovering a new world. That was a turning point.

Then I completed my studies, and when it was time to start Univerisity, I already knew I wanted to do marine biology. As I felt what is the feeling of breathing underwater, if we can bring more people not necessarily breathing underwater but even just swimming in the sea, they can recognize how important it is to protect the environment and everything related to the ocean. People do not care because they cannot see what is underwater.

We cannot bring everyone underwater, that’s why we need more science communication to reach the ones that cannot physically be there.

Let’s close this interview by advertising diving for my readers. Fill us with envy: Where have you been diving? And what’s the most beautiful sea for diving that you have experienced?

I have been diving in many places in the Mediterranean sea. West coast of Italy, which I still think is one of the best places in the world. Red sea, Indonesia, Hong Kong. I think the Italian sea is still the best. When you live there, you do not recognize the strength and the power of marine Italian environment. The west coast, near Tuscany, is still one of the best places I have been diving.

You should really think about taking a diving course!

Read more about Walter

I spent a little bit more time talking about life in Hong Kong and Walter’s projects for his next career step. You can listen to the whole interview on Youtube, where I have a few recordings of the drawing process of the illustrations on this blog post.

If you want to check out more of Walter’s work, you can reach him on his social media, on twitter @WDellisanti or on Instagram @dellwalter88.

How to support Draw My Science:

“Draw My Science” is the project where I interview scientists and make editorial illustrations inspired by their work, that they can use for any non-commercial activity.

If you like the project and want to help keep it going, you can support me on Ko-fi or buy items from my shop.

If you are a scientist and would like to be selected for “Draw My Science”, subscribe to my newsletter. That’s where I will announce the next selection round for this project.

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