Baltic Sea life under siege from pollution, warming

Marine life in the Baltic Sea is facing increasing pressure from climate change, pollution, and human activity, raising concerns among scientists and environmental groups about the long-term health of one of the world’s most fragile marine ecosystems, Anadolu Ajansı reports.

The Baltic Sea, bordered by Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Poland, Germany and Denmark, is almost entirely enclosed by land and connected to the North Sea only through narrow, shallow straits.

These unique geographical conditions make it particularly vulnerable to environmental degradation and slow recovery.

Coastal states, largely in cooperation with the European Union, have stepped up efforts to address the growing threats. The Baltic Marine Environment Protection Commission (HELCOM) continues to implement the Baltic Sea Action Plan, which aims to protect fish stocks, marine mammals, birds and key habitats.

Anadolu’s ongoing “Baltic Sea” series examines the main challenges facing the ecosystem and the policies being pursued by regional actors.

Eutrophication a major threat

One of the most serious challenges confronting the Baltic Sea is eutrophication — the excessive enrichment of water with nutrients such as nitrogen and phosphorus. These nutrients mainly originate from agriculture, sewage and industrial discharge and fuel large-scale algal blooms.

The blooms block sunlight from reaching underwater plants and seagrasses, while the decay of algae consumes oxygen in deeper waters, creating so-called “dead zones” where most marine organisms cannot survive.

Because the Baltic Sea is nearly landlocked and has relatively low salinity, scientists warn that oxygen depletion could intensify in the coming decades. Studies also predict increasing acidification of its waters.

Anna Klemela, a researcher at the Finland-based Baltic Sea Action Group (BSAG), told Anadolu that reducing nutrient inputs from land is one of the most important steps toward protecting the sea.

“The majority of nutrient loads come from agriculture and forestry,” she said, adding that improved fertilizer management, sustainable farming practices and better wastewater treatment are essential.

HELCOM promotes measures such as limiting sewage discharges and encouraging efficient fertilizer use to reduce runoff entering the sea through rivers and groundwater.

Overfishing and human impact

Human activities beyond pollution are also contributing to the Baltic Sea’s ecological decline. Overfishing has significantly reduced fish stocks, particularly cod, whose populations have fallen sharply in recent decades.

Germany’s GEOMAR Helmholtz Centre for Ocean Research says intensive fishing has not only reduced cod numbers but also caused lasting genetic changes, with fish becoming smaller — often by as much as 20 centimeters.

According to the World Wide Fund for Nature (WWF), overfishing continues to threaten several species in the Baltic ecosystem. The European eel is now on the brink of extinction, while the population of harbor porpoises has fallen to around 500 individuals.

Poor waste management and marine litter further exacerbate the pressure on marine habitats, environmental groups say.

Long-term recovery uncertain

Monitoring and modeling studies conducted by HELCOM and BSAG indicate that conditions in the Baltic Sea would be significantly worse today without nutrient reduction measures introduced since the 1980s.

Nevertheless, underwater biodiversity continues to decline, compounded by climate change, which intensifies risks such as oxygen loss, habitat shifts and species disappearance.

Experts caution that the ecosystem’s degradation occurred over several decades, meaning recovery will also take a long time, even if current policies are fully implemented.

Under the updated Baltic Sea Action Plan adopted in 2021, the nine coastal countries have committed to implementing concrete measures by 2030 to reduce pollution, improve water quality and strengthen ecosystem resilience. Progress is monitored through regular reporting and binding commitments under EU-HELCOM cooperation.

The EU is also funding efforts to remove unexploded ordnance, chemical munitions and shipwrecks dating back to World War II, which continue to pose environmental risks on the seabed.

Concerns over underwater infrastructure have grown since the 2022 Nord Stream pipeline explosions, prompting increased EU scrutiny of seabed security and environmental remediation.

While regional cooperation has intensified, scientists and environmental groups warn that sustained political will and long-term investment will be crucial to prevent further deterioration of the Baltic Sea and to give its unique ecosystem a chance to recover.

By Aghakazim Guliyev