Island, 1974:
Michael Melkonian fishes a sample of the genus Glenodiniopsis out of a small pond, thus marking the beginning of the world’s largest collection of algae, now located at UDE. Currently, 7,462 cultures are distributed among vials and test tubes in five climate chambers in the basement of building S05 at the Essen campus. Around 4,420 of them were established by the now emeritus professor of botany himself. Growth media, temperature, and lighting are individually adjusted to the specific needs of the species – now the responsibility of curator Dr Sabina Marks and three technical assistants.

Algae produce around 50 per cent of the world’s oxygen. The Central Collection of Algal Cultures (CCAC) contains representatives of all major groups: brown, green, and red algae, as well as blue-green algae, diatoms, and various flagellated protozoa. The collection grows steadily thanks to submissions from scientists worldwide: ‘If you conduct and publish research with algae, you have to deposit them in such a way that others can reproduce the experiments,’ explains Sabina Marks. In this way, the collection at UDE ensures the permanent preservation of the cultures and maps the constantly changing biodiversity. In the future, samples of individual species will also be preserved at low temperatures (cryoconservation).

Most cultures in the collection prefer a temperature of  15 to 23°C. ‘But we also have Antarctic species that need to be kept at 4°C. Others survive for just a few days without light,’ says Marks, hinting at the challenges maintaining such a collection entails. Researchers worldwide can order cultures for a fee of 65 euros, for example for experiments on water treatment or on the breakdown of plastic. The bestseller is the low-maintenance freshwater algae Chlorella. Artists are more likely to choose luminescent species. Schools receive samples for teaching purposes free of charge.