April 3, 2020

Nordkalk donates limestone to the SEABASED-project

Nordkalk donates limestone to the SEABASED-project for piloting a measure that could bind eutrophying phosphorus permanently into the sediments of the seabed. In the project, three pilots at selected areas with activated limestone application to phosphorus containing bottom sediments will be implemented in chosen pilot sites in coastal bays in Sweden (Östergötland and Stockholm) and Finland (Archipelago Sea). The crushed limestone will be pre-treated by burning at facilities of Cementa in Gotland and then transported to the pilot sites and spread over the seabed to bind phosphorus into the sediment.

“For Nordkalk, operating by the Baltic Sea in Sweden and Finland, protecting our common sea is a natural choice of action. By donating the limestone for binding phosphorus, the company can take part in a concrete action for promoting the wellbeing of the sea”, says Mathias Snåre, Head of Research & Development at Nordkalk. The limestone used for the project originates from Nordkalk’s quarry in Gotland. And, if the project pilot turns out successful, there is enough material existing for treatment of several other anoxic seabed areas in the Baltic Sea, if needed.

The piloted method is based on several years research of scientists Sven Blomqvist and Eva Björkman at Stockholm University. In the SEABASED-project, the method will be now tested outside the laboratory for the first time. The work in SEABASED was started with defining the exact amounts of limestone for binding phosphorus in the pilot sites. The first application was implemented in a coastal bay in Kyrkviken, Sweden last September. The rest of the pilots are in permitting phase and are expected to be implemented during 2020. After the activated limestone has been applicated to the pilot sites, the effects of the measure on phosphorus and oxygen concentrations at the seabed and in water, as well as on the biota, will be followed thoroughly.

The laboratory results for using activated limestone in binding phosphorus have proven to be very promising. As a natural material, limestone is not foreseen to pose any harm to the marine environment but could be potential in reducing the release of phosphorus from anoxic seabeds, and, thus, also for reducing the harmful algal blooms that utilize the phosphorus for their growth. “We are grateful to Nordkalk for their donation, that enables the three pilot-scale tests for the measure”, says Miina Mäki, Project Manager for the SEABASED project at the John Nurminen Foundation. “Without coming out from the laboratory with controlled pilots, we would never be able to find out whether this method could be one of the future solutions for helping the Baltic Sea.”

The SEABASED Project (Seabased Measures in Baltic Sea Nutrient Management) pilots and assesses measures that could improve the status of a marine area by reducing the internal load of the sea. Selected measures will be tested in small-scale pilot areas in Finland, Åland and Sweden. 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 total budget for the project is approximately 2.8 million euros of which 2.1 million euros is co-financing from the EU Interreg Central Baltic programme.

Read more about the pilot on our webpage.

More information:

John Nurminen Foundation

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

Miina Mäki
Project Manager
Clean Baltic Sea Projects, John Nurminen Foundation
tel +358 50 576 3298


Nordkalk is the leading company providing limestone-based products and solutions in Northern Europe, with a significant presence in Central Europe, with operations in more than 30 locations in Europe. The company employs around 870 people, and in 2019 it had a turnover of almost EUR 300 million. Nordkalk is owned by Rettig Group. http://www.nordkalk.com

Mathias Snåre (Dr. Tech)
Head of Research & Development
Nordkalk Corporation
Tel. +358 (0)207 53 7344
Mobile +358 (0)400 96 7711

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