Scientific institutions in seven countries have appealed to the greater scientific community and policymakers to use the Baltic Sea region as a model for coming changes in the global coastal ocean.
The Baltic Sea provides useful lessons for how negative trends can be reversed by protective measures. In the international journal Science Advances, an international team of researchers led by the GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, promotes the Baltic Sea as a time machine for global coastal ocean.
Major changes being observed or expected for the future in coastal zones of oceans around the world include:
- Eutrophication; and
- Loss of oxygen.
The Baltic Sea seems to be rather uninteresting for scientists working on global ocean topics. It is comparatively shallow, has a low salinity and only a very narrow connection to the North Atlantic.
Professor Thorsten Reusch from the GEOMAR Helmholtz Center for Ocean Research Kiel, one of the lead authors of the article, said: “This unique sea of brackish water can serve as a kind of time machine that allows us to better estimate future global changes.”
How can the Baltic Sea help scientists?
Scientists argue that changes that are only expected for the future in the global ocean can already be observed in the Baltic today.
Reusch said: “This is because the small volume of water and slow water exchange with the open ocean behaves like an amplifier, allowing many processes and interactions to occur at a faster pace.”
According to GEOMAR, the oceans have warmed by an average of 0.5°C over the past 30 years; in the same period, measurements in the Baltic Sea have recorded warming of around 1.5°C. Similarly, there are large oxygen-free zones in the deep areas of the Baltic Sea, which have increased tenfold over the past century; and the pH of Baltic waters regularly reaches values that are expected in other ocean areas only in the next century.
Reusch concludes: “Overfishing, warming, acidification, pollution, eutrophication, loss of oxygen, intensive use of coasts – all these are phenomena that we observe around the globe. Because they have been particularly drastic in the Baltic, but also because some key problems were successfully addressed, the region can, for good and for bad, tell us what to expect and how to respond to the challenges of the future.
“The Baltic Sea, as a model region, can contribute to achieving the United Nation’s Sustainable Development Goal 14 – the conservation and sustainable use of the oceans, seas and marine resources.”