Original article by Heidi Volotinen, WWF Finland

The Baltic Sea is facing many challenges. Its enchanting coastline suffers from poor water quality, and eutrophication is simplifying its marine environment. The protection and restoration of the Baltic Sea are vital for securing its future.

Unique, delicate, and significant – that’s what the Baltic Sea represents. Many Finns seek solace and tranquillity by its shores. Life’s important and celebratory moments are spent on its beaches, where people learn to swim and fish, ice fish and ski. The Baltic Sea welcomes sailors, cruisers, and professional fishermen alike. It builds a connection between people and nature.

Unfortunately, the Baltic Sea is also one of the most polluted seas globally, suffering especially from eutrophication and water turbidity. The effects of eutrophication become obvious. When toxic green algae blooms await in the water during hot summer days, leading to cancelled swimming trips. In Finland, the coastal waters of the Baltic Sea are in deplorable condition.

The Baltic Sea is a small and shallow sea with slowly changing water, a mix of freshwater from rivers and saltwater from the open ocean. Only a few species thrive in the brackish waters of the Baltic Sea. It’s too salty for many freshwater species and too freshwater for oceanic species. However, the habitats for Baltic Sea species have changed. Warmer seawater and changes in salinity affect underwater vegetation and the living conditions of fish. The Baltic Sea’s water is low in salt and stratified, exchanging slowly with the seawater flowing through the Danish straits from the North Sea. Due to favourable weather conditions, more saline water from the North Sea flows into the Baltic Sea in salt pulses approximately every ten years. These salt pulses mix the water and reduce bottom oxygen deficiency. Over the past decades, salt pulses have become less frequent, leading to an increase in oxygen-deprived bottoms. Species like whitefish and perch, which prefer cooler and oxygen-rich waters, suffer from the changes in the Baltic Sea.

Water conservation plays a crucial role in mitigating eutrophication in the Baltic Sea – but what does it mean?

When viewed on a map, there is a clear, precise boundary drawn by the shoreline between the Baltic Sea and the land. It is accurate and straightforward: here is where the land ends and the sea begins. However, reality is not as straightforward. There is a connection between land and sea.

The coastal waters are dark and murky, making it difficult to see the bottom even in deeper waters. Over decades, due to human activities, the Baltic Sea has received an excess of nutrients, causing excessive growth of algae and aquatic plants. This has created a harmful cycle in the Baltic Sea: the more algae there is in the water, the more oxygen is consumed on the seabed. Oxygen-deprived and low-salinity water is not an ideal habitat for Baltic Sea species. Due to the oxygen deficiency in deep seabed areas, most of the Baltic Sea’s cod breeding and living areas have already been lost.

There is a risk that the underwater world of the Baltic Sea will become less diverse. There are already areas on the Baltic Sea floor where no life exists. It is crucial to take care of species that are important for the biodiversity of the Baltic Sea, such as bladderwrack, bladderwrack, and blue mussels. They provide shelter and food for many Baltic Sea species.

Rivers and streams are part of the connection between land and sea. The flowing waters from the coastal areas eventually flow into the Baltic Sea, carrying nutrient and sediment loads washed away by rain and floodwaters from nearby fields and commercial forests. Due to climate change and the increased occurrence of weather phenomena like droughts, heavy rains, and floods, there is an increasing influx of nutrient load into the waters. Floods in both agricultural and forested areas during mild winters and spring have become more common, for example, in the West Uusimaa region.

Slowly and meanderingly flowing water is a positive sign. Efforts are being made to reduce the flow of nutrients and sediments into the Baltic Sea by slowing down water flow and increasing the water retention capacity of drainage basins. This is about water conservation, which is an umbrella term for various actions taken in watershed areas to mitigate environmental stress caused by human activities. The large volumes of water generated by heavy rainfall events may not always fit within the original watercourses and may spill over onto fields. In such cases, one solution is to construct two-tier channels, which improve the area’s ability to retain water by providing more space for water to gather: the water rises from the original watercourse to a higher-level, vegetation-covered flood terrace. Vegetation-covered flood terraces release less sediment into the water than fields do.

Five Years of Water Conservation Work in Western Uusimaa – Strong Interest in Water Conservation

Landowners play a crucial role in maintaining the good ecological status of water bodies. WWF began its water conservation work in Western Uusimaa in collaboration with landowners five years ago, and it was soon observed that the flood-prone agricultural and forestry areas had a particularly significant need for water management.

The explanation for this can be found in recent history. Human activities have altered the landscape: in Finland, extensive ditching, straightening of stream channels, and drainage of naturally water-retaining wetlands and marshes were carried out in the past. This has resulted in waters, along with their carried nutrients and sediments, flowing directly from fields, forests, and residential areas into rivers and streams, which then transport these substances further into the Baltic Sea. Rectifying the damage takes time, but through persistent efforts, water bodies can achieve a better ecological status.

In five years, a lot has been accomplished in Western Uusimaa. In collaboration with landowners, WWF has constructed over 20 wetlands, numerous two-tier channels, and bottom thresholds in the area. Additionally, straightened watercourses have been restored to their natural forms. Jenny Jyrkänkallio-Mikkola, WWF’s Inland Waters Coordinator, has been leading WWF’s water conservation work in Western Uusimaa since its inception. She emphasizes the importance of collaboration with landowners for the improvement of water bodies.

“Landowners play a key role in the protection of the Baltic Sea and other water bodies. In numerous projects, we have witnessed the enthusiasm and willingness of open-minded landowners to engage in water management measures such as constructing wetlands and two-tier channels,” says Jyrkänkallio-Mikkola.

The future prospects for water conservation work are promising, and the list of water conservation projects awaiting implementation is long.

“It can be said that there has been a systemic change in water conservation in the area, as landowners’ interest in these projects exceeds the current funding available. It would be a great pity to miss this opportunity.”

According to Jyrkänkallio-Mikkola, efforts to improve water management in the project area will continue persistently in the future. However, the prerequisite for this work is ongoing funding.

“Especially the Water Management Enhancement Program has been a significant source of funding for our work.”

Ensuring the continuity of water conservation work is crucial for the Baltic Sea because it helps reduce the stress on the sea. Conservation and restoration efforts help maintain the health of water bodies and the balance of ecosystems, as well as secure a more sustainable environment for future generations.

“In my hopes, streams would be clear again, diverse, and teeming with life, and the watercourses would be free, allowing migratory fish to ascend and spawn. I hope that river water would be clearer, and the riverbanks wooded. Looking beneath the surface of the Baltic Sea, it would be wonderful to see several meters deep and admire bladderwrack free from filamentous algae, red algae, blue mussels, bladder wrack, and flounders.” Jenny Jyrkänkallio-Mikkola