25.01.2021

Key conclusion from the SEABASED project: no silver bullet for reducing internal nutrient load

The SEABASED Project (Seabased Measures in Baltic Sea Nutrient Management), led by the John Nurminen Foundation and funded by the EU, examined measures that potentially could improve the state of the Baltic Sea by reducing the internal nutrient load of the sea. Although some of the piloted methods show great potential, no silver bullet was found to quickly relieve the nutrient load and eutrophication troubling the Baltic Sea. However, some methods for reducing internal load can be useful for improving the environmental conditions in heavily eutrophied, relatively enclosed small bay areas.

Baltic Sea protection should focus on reducing nutrients coming from land

The sea-based measures can be efficient in reducing the internal nutrient load only if the load from land is tackled at the same time. Even though some of the new techniques may seem promising, none of them is mature enough for achieving quick results in cutting the load from the seabed. Although due to high cost and risks the methods are currently not suitable for large-scale open sea area usage, some methods can be helpful for enhancing the recovery of heavily eutrophied, relatively enclosed small bay areas. Therefore, our project’s results underline the importance of continuing the work in reducing the nutrient load from land-based sources.

“One of the most significant results of the SEABASED Project has been the new knowledge achieved when implementing the practical pilots. In marine protection, like in any other investment, the focus and resources should be directed to the efforts which bring the biggest benefits and effect. With the information gathered on the effects and costs, the selected sea-based measures can be included in the discussion on more realistic basis when deciding on the future focus and efforts in Baltic Sea marine protection”, Project Manager Miina Mäki concludes.

An important outcome of the project is that it is crucial to include proper environmental monitoring of impacts for several years when planning future research and pilot projects for reducing internal nutrient load. Due to lack of monitoring, many of the previous pilots implemented in the Baltic Sea have produced little information for assessing the measure’s impact on internal load.

Project learnings to be collected into practical guidelines

The findings underline that it will be important to continue decisive actions in reducing the nutrient load to the sea also from sources on land, while developing further the sea-based measures.

”The John Nurminen Foundation has been working with concrete measures to decrease land-based pollution from municipal and industrial point sources as well as agriculture since 2005. We initiated the project to understand better the cost-efficiency and feasibility of novel measures to decrease internal nutrient load of the Baltic Sea.” says Annamari Arrakoski-Engardt, CEO of the Foundation.

The project’s results will shine a light on the processes, regulation, and cost-effectiveness of different sea-based measures. This valuable knowledge on future development needs as well as potential benefits of each measure will be compiled into practical guidelines to help Baltic Sea protection in the future.

Results from the project pilots and their implications were discussed in a webinar organised by the SEABASED project on January 26th, 2021. YThe recording of the webinar and presentations are available on the project website.

Further development and research required

The SEABASED project piloted and assessed measures that seek to improve the status of the selected sea bays by reducing the internal load of the sea. Some of the measures can also support the circular economy by recycling nutrients from sea to land. In the project recycling of the nutrient-rich water for irrigation of fields, binding of phosphorus in the seabed sediment by using natural, limestone-based material (heat-treated marl) and fishing stickleback to enhance predatory fish populations were piloted in Finland, Åland and Sweden. In addition, artificial reefs, and instructions for making a pike factory, a wetland to enhance pike populations, were made in Sweden, and a concept for aquatic compensations was designed, related to the renovation of the Water Act in Åland. The potential of sediment top-layer removal for phosphorus uptake and reducing the oxygen demand in the bottom was studied with incubation tests in laboratory scale.

The results from the field pilots and information gathered from previous projects show that while some measures, like removing sediment’s active, oxygen-consuming surface layer were deemed too costly and ineffective, some, like the awarded innovation of spreading activated limestone to bind phosphorus to the seabed, have potential to be effective but still need further development and research.

“The nutrient loading from the catchment area must be reduced, but at the same time there is need to know if it is possible to use sea-based measures to improve the status of the Baltic. It is important to raise knowledge through small scale experiments and pilot projects, which has been done in the SEABASED-project”, states Senior Research Scientist and SEABASED Steering Group member Jouni Lehtoranta from the Finnish Environment Institute (SYKE).

Further information:

Miina Mäki
Project Manager of the SEABASED Project
John Nurminen Foundation
miina.maki (at) jnfoundation.fi
tel. +358 (0)50 576 3298

Kirsi Kurki-Miettinen
Communications Officer
John Nurminen Foundation
kirsi.kurki-miettinen (at) jnfoundation.fi
tel. + 358 (0)50 463 9305

 The SEABASED Project

The SEABASED project is led by the John Nurminen Foundation, and the project partners are the Centre for Economic Development, Transport and the Environment for Southwest Finland, Government of Åland, the Åland Fishfarmers’ Association, Stockholm University and County Administrative Board of Östergötland. The project is funded by the EU Interreg Central Baltic programme. Visit the project’s website for more information: https://seabasedmeasures.eu/.

John Nurminen Foundation – Baltic Sea protection and marine culture

Founded in 1992, the mission of the John Nurminen Foundation is to save the Baltic Sea and its heritage to future generations. The Foundation has been awarded for its work as a conveyor of culture and producer of marine content. The goal of the Foundation’s Clean Baltic Sea projects is to improve the condition of the Baltic Sea with concrete measures that reduce the load and environmental risks faced by the sea. Our work is guided by measurable results and impact. www.johnnurmisensaatio.fi/en

Photo: Tara Jaakkola / John Nurminen Foundation

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