Preserving a window into the Baltic Sea of 1938
In 1938, the algae researcher Mats Waern collected samples of Baltic Sea vegetation. Almost ninety years later, herbarium specimens from that work have been brought to Ocean Archive by marine ecologist Nils Kautsky, Professor Emeritus at Stockholm University.
Waern (1912-1998) became one of Sweden’s prominent researchers on algae and was a pioneer of scientific diving. Long before modern scuba equipment was widely available, he developed methods for observing and collecting algae beneath the surface. His detailed surveys of Swedish coastal waters later became valuable reference points for scientists studying environmental change.
Decades after Waern’s fieldwork, researchers including Nils Kautsky returned to some of the same areas. By comparing their observations with Waern’s historical records, they could document substantial changes in Baltic Sea vegetation. A study published in 1986 showed that bladderwrack (Fucus vesiculosus) no longer grew as deep as it had in the 1940s. This was evidence of the long-term effects of eutrophication and reduced water clarity.
Together with information about where and when it was collected, a herbarium specimen becomes a measurable snapshot of an ecosystem at a specific moment. Ocean Archive will now photograph and document the specimens, creating a high-resolution digital record while the originals are preserved.
Nils Kautsky could return to Waern’s records decades after they were made. In the same way, Ocean Archive aims to give future researchers access to Waern’s work and to material from other donors, as an open resource for comparing past and present ocean conditions.
