GAME 2020 - a Master's thesis at the OSCM
28 Mai 2021 / Kiel - Mindelo
GAME 2020 - About attachment behavior and diving experiences in Cabo Verdean waters - a Master's thesis conducted at the OSCM
Sabine Weidlich from the University of Vienna spent almost seven months on the Cape Verdean island São Vicente at the Ocean Science Centre Mindelo (OSCM) to conduct her master thesis as part of the international training programme Global Approach by Modular Experiments (GAME). This is already the third generation of GAME students that have used the OSCM as basis for their research activities.
The GAME programme combines basic research with training of students from Germany and partner countries all over the world. Every year the programme kicks off in Germany at GEOMAR Helmholtz Centre for Ocean Research Kiel. During the first month of the programme, the students are located at GEOMAR to form bi-national teams and to develop the methodological approach of their research project. After this initial phase, the teams leave Kiel to start the practical project part at their respective partner institutes abroad. Once the practical phase is completed, the participants return to GEOMAR to analyse their findings and to write up their thesis.
In the following, we will report about Sabine's GAME research project, which is also her master's thesis, and about the experiences and impressions, she gained during her time on Cabo Verde. Sabine started the practical part of GAME at the OSCM supervised by her home university advisor and by the local advisor Prof. Dr. Corrine Almeida from the Atlantic Technical University of Cabo Verde (UTA) as well as by Dr. Mark Lenz from GEOMAR in mid-August 2020. Sabine’s research project focused on the impact of plastic debris to the functioning and structure of aggregates of Cabo Verdean Brachidontes mussel. The overarching theme of her thesis was 'marine litter as a vector'. As nothing was normal and even less predictable in 2020, the start of the practical phase brought a surprising twist right at the beginning for Sabine. One of her pilot studies showed that the local mussels neither form aggregates nor likes to settle on plastic surfaces. This surprising new finding made the intended model organism unsuitable for the planned study. Consequently, the experimental design had to be adapted to the new situation. Full of enthusiasm and undaunted by the new situation, Sabine restarted with an alternative approach in November 2020.
Her new research project comprised three experiments, which investigated (1) which substrate preferences local mussels’ exhibit, (2) how long they can remain attached to certain substrates, (3) which organisms colonize different substrates. A marine litter monitoring complemented these experiments. In the first experiment, four different substrates (wood, glass, polypropylene and polystyrene) were offered to the mussels and then tested which surfaces where preferred for attachment. The result of this laboratory experiment was that the mussels preferred to attach to rough surfaces rather than to smooth ones. In the second laboratory experiment, Sabine let the mussels attach to wood and polystyrene substrates over the course of a week. Then she recorded how many mussels had attached to the substrates. Following this initial count, the attached mussels were transferred from the OSCM aquarium to the marina of Mindelo, São Vicente. Exposed to this new environment, Sabine recorded again in a rhythm of 3, 7 and 14 days the number of mussels that remained attached. Based on her counts, she found that more mussels remained attached to the artificial polystyrene substrate. While counting underwater, she sometimes had visits from turtles strolling through the marina searching for food, which made the underwater work very special for her. In her third experiment, the same four substrates were exposed to the natural pool of colonizers in the Mindelo marina. After two months, Sabine evaluated the fouling status of the different substrates and found that the dominating taxonomic group were Bryozoa. As an enthusiastic diver, working underwater was particularly attractive to Sabine and represented a unique element of her work on Cabo Verde. As soon as the underwater work was completed, it was time to start the fourth and final investigation. This took Sabine to the beach to investigate marine litter and check for its potential function as a vector for sessile organisms such as mussels. In this experiment, she monitored beach litter at five different beaches on São Vicente according to a standardised scheme by using 100 m transects. All beaches monitored had a different geographical orientation and were at least 1 km long. Analysis showed that one beach in particular, oriented in a north/north-east direction, had a large amount of trash washed up. Interestingly, these litter items carried a large number of associated organisms living on their surface.
In spite of the special pandemic situation, which made day-to-day work much more difficult, Sabine looks back with satisfaction on a successfully completed research project. She is particularly thankful for the help and support she received from the OSCM team, which supported her in every situation. Moreover, she is particularly impressed by the politeness and hospitality of the local residents. Especially hospitable and very interested were the people who lived just outside the city of Mindelo. Sabine explained that she never had a rural bus ride without a spontaneous conversation. After her work at the OSCM was finished, Sabine took a room in São Pedro, where she also ran into her new flat mates and future Austrians Pauli and Rumo. The two Cabo Verdean cats have grown so fond of Sabine that she decided to take them with her to Austria. Fully vaccinated and vet-checked, the kittens now have a new home in Vienna. Besides the politeness and hospitality of the locals, Sabine was very impressed by the beauty of the island's nature. She was especially taken by the mountain scenery of the island and of the diversity and beauty of the underwater world. Much of her spare time was spent underwater and Sabine quickly made friends with the local divers, soaking up the underwater world of São Vicente enjoying encounters with manta rays, nurse sharks and huge schools of fish.
If you want to learn more about GAME, click here: https://www.geomar.de/go/game
Caption from left to right:
I. Green turtle (Chelonia mydas) with swimmers (top left in the picture Sabine Weidlich) underwater off the Cape Verde island São Vicente. Picture credit: Rivaldo Lima Dá Luz (diving centre Dive-Tribe, São Vicente).
II. Sabine Weidlich checking her experiments in the Mindelo marina, Mindelo, São Vicente, Cabo Verde. Picture credit: Eritson Fonseca.
III. Eritson Fonseca (Sabine's GAME team partner) analyzing a settlement plate in the OSCM laboratory. Picture credit: Sabine Weidlich.