Paper short abstract:

Algae are increasingly perceived as ‘natural resources’. We explore the changing understanding of the algal world in the Baltic Sea region by investigating cases of algal blooms in brackish and freshwater ecosystems and the growing recognition of stonewort meadows as engineers of healthy ecosystems.

Paper long abstract:

The underwater world remains an unknown and untamed territory for humans, yet they continue to attempt to manage, control and extract from it. Algae, despite limited knowledge of their role as contributors to highly productive and biodiverse ecosystems and as indicators of ecosystem health, are also increasingly perceived as ‘natural resources’. In November 2022, the European Union published a press release ‘proposing measures to fully exploit the potential of algae in Europe for healthier diets, lower C02 emissions and to combat water pollution’. The Action Plan has been developed to support and create opportunities for the growing potential of the algae industry, with demand expected to reach €9 billion by 2030. The largest potential markets are considered to be the food market, but also cosmetics, pharmaceuticals and energy production (European Commission 2022).

As our research shows how intertwined human life is with the underwater world, and more specifically with algae, we want to examine the changing understanding of this world and life in the Baltic Sea region. We explore the complex relations between humans and the group of organisms commonly (and often inaccurately) known as ‘algae’ by looking at two cases: 1) harmful algal blooms (HABs) in the Finnish Archipelago (cyanobacteria) and in the River Oder on the German-Polish border (golden algae), and 2) the recognition of stonewort meadows as ecosystem engineers in Central European glacial lakes. We investigate how these human-algae ‘interfaces’ are interpreted, managed and reconsidered.