Traze luz n escuridao – What happens to macroalgae when we deprive them of darkness? Pioneering research in Cabo Verde

Oi tud drt? – To read this Kriol words here, to say “Hi, everything fine?”, means GAME is back in Cabo Verde.

This year, Melanie (Universidade Técnica do Atlântico, Cabo Verde) and Lotte (University of Freiburg, Germany) have the chance to experiment together as a binational team on a still largely unexplored topic: the influence of artificial light at night (ALAN) on macroalgae. 

As the plane approaches the archipelago of volcanic origin with its collar mountains, in the middle of the ocean, it becomes clear that the small island of São Vicente (with an area only twice the size of Kiel) is a very special destination for our research. We are located in Mindelo,  the capital of the island with around 75 000 inhabitants. São Vicente is one of ten islands of the archipelagic country, which is located just over 600 km off the coast of Senegal. The isolated location, surrounded by nothing but the sea and the sun, will give us a lot of pleasure and at the same time present us with many challenges. We would like to give you an insight into our daily (research) life.

As other GAME 2024 teams already presented, we are researching the influence of ALAN on macroalgae. The topic follows the research series on ALAN of the last GAME years, but for the very first time photoautotrophic organisms are considered. We raise the question whether macroalgae, as light-dependent organisms, change their properties in response to ALAN. To do this, we observe growth rates, photosynthesis rates and possible defense capacities against grazing in a laboratory experiment.

If in the evening you sit in a bar on the jetties of Mindelo, the research topic again becomes very real. Various species of macroalgae shine in the light of the harbour. A total of 330 species of macroalgae have been described for the archipelago. And even if this diversity is not yet available for our research, on an island state so far away from the mainland, the sea and all its biodiversity have a special importance. The Ocean Science Center Mindelo (OSCM) as a research hub for marine sciences between the European and African continent is therefore a perfect location for this international project. The OSCM currently houses our aquariums and with that is our current center of life.

The warm and open atmosphere of Mindelo makes it very easy to feel at home. And whether in a research context or in the remaining leisure time the island of São Vicente has much to offer for both, a marine biologist and a tourist. Every excursion to collect the experimental organisms is a small insight into the huge biodiversity of the tropical Atlantic. Whether corals, algae, starfish, crabs or creatures, that at least Lotte had no idea existed, the variety of colors and shapes is impressive. 

And if you take a short trip to another beach in Sao Pedro on the weekend, you will find yourself in the breathtaking experience of swimming with turtles (Chelonia mydas).

But for all the beauty of the picturesque island life, the availability of everything is sometimes limited. So the answer to the question “where can we get that?” is often a laugh. This always gives you the chance to show creativity and to practice patience. Especially in the beginning, a short errand can turn into hours of walking through the small stores of Mindelo. And without a local person and fluent Kriol it seems an impossible challenge to simply buy things, find the way to the next shop or get technical help. But with a certain amount of acceptance and perseverance, we managed to build a suitable set-up and get (almost) everything we needed.

We are currently preparing our second experiment. In which Echinometra lucunter will again be the grazer and the choice of algae species is still in process. The sea urchin species Echinometra lucunter is found in the western Atlantic Ocean and the Caribbean Sea. It can grow to a diameter of about 8 centimetres. The color varies from black to deep brownish-red.

But even if the project sometimes gives us many causes for concern, jumping into the waves on the Atlantic in the evening can always clear your mind and refresh you for the next day.

Cheers,

Melanie & Lotte