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Common Eelgrass – A Key Species of the Baltic Sea

Common Eelgrass – A Key Species of the Baltic Sea

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Common eelgrass, a key species of the Baltic Sea, forms meadows that provide shelter for dozens of species and play a vital role in protecting underwater biodiversity.

Seagrass meadows – the Baltic Sea’s own coral reefs

Seagrass meadows are full of life, much like coral reefs. They provide food and shelter for many other species. Snails and crustaceans, among others, graze safely within these meadows.

Seagrass meadows spread across wide areas, binding bottom sediments and thereby reducing erosion. The meadows also absorb nutrients from the water and help reduce turbidity.

In the southern Baltic Sea, where growing conditions are favorable, seagrass meadows also act as carbon sinks.

leväsiira ja meriajokas
Idotea balthica (leväsiira), a common isopod found in Baltic Sea eelgrass meadows. Photo: Pekka Tuuri

Eutrophication threatens common eelgrass meadows

Primary as a result of eutrophication, common eelgrass seabeds in Finland’s maritime areas have been classified a Near Threatened habitats.

Eutrophication, caused by excessive nutrient levels in the sea, increases water turbidity, limiting the light available for common eelgrass to grow. Filamentous algae, which thrive in nutrient-rich waters, outcompete common eelgrass by smothering it and taking over its habitat.

In addition to eutrophication, coastal construction and dredging of sandy bottoms disturb the meadows.

Sukeltaja tutkii merenpohjan meriruohoa
Photo: Olli Mustonen

Restoring seagrass meadows supports biodiversity

The good news is that the nutrient load to the Baltic Sea has been cut: this means that common eelgrass has a chance to once again thrive in the sea.

Seagrass meadows can be restored by transplanting common eelgrass seedlings into areas where they have previously grown, but have disappeared from – mainly due to eutrophication. The results of the plantings already done are encouraging.

Meriajokas Itämeren pohjassa
Projects
Baltic Seagrass project

The project restores seagrass meadows on Finnish coast in areas where they have declined. Common eelgrass is one of the key species forming underwater habitats on the Baltic Sea coast.

John Nurminen Foundation has restored eelgrass meadows with partners along the Finnish coastline in Helsinki and Hanko. In 2025 and 2025 we are expanding our efforts and transplanting eelgrass in Sweden, where we cooperate with the m unicipality of Kristianstad and Vattenrike Biosphere Reserve.

On top of restoration work our plan is to strengthen people’s connection to the sea: we need to transform the unsustainable human action in order to halt nature loss.

lähikuva Itämeren meriajokkaasta
Projects
SeaToo

We prevent the loss of nature in the Baltic Sea by restoring underwater habitats and promoting sustainable use of marine resources. Read more!

Marine nature restoration measures support the goals of the EU Biodiversity Strategy, the Restoration Regulation, and the UN Nature Conference (COP 15) to protect and restore 30 percent of marine nature by 2030.

The Baltic Sea needs your help.
It’s not yet too late to save the sea.

Photo of eelgrass: Pekka Tuuri. Photo of LOCUS artists Thale Blix Fastvold ja Tanja Thorjussen: Ole Løvold – Thale Fastvold

Imagining a utopian future for common eelgrass at Helsinki BIennial 2025

Helsinki Biennial is an international art event that brings outstanding contemporary art to Helsinki’s archipelago nature. The John Nurminen Foundation is a partner of the event and supports the artwork production of LOCUS / Thale Blix Fastvold and Tanja Thorjussen.

In their work, the LOCUS artists envisage a hopeful, speculative, utopian future for common eelgrass, which they imagine as blooming and thriving in the Baltic Sea.

The work of LOCUS can be experienced at Helsinki Biennial in Vallisaari and HAM Helsinki Art Museum.

meriajokasta
Event
Helsinki Biennial 2025
lähikuva Itämeren meriajokkaasta
News
Envisaging a utopian future for common eelgrass at Helsinki Biennial 2025
Itämeren vedenalainen maisema, jossa meriajokasta kasvaa hiekkapohjalla.
Press release
The John Nurminen Foundation is working with Metsähallitus to restore seagrass meadows to new areas
meriajokas
News
Changing the unsustainable use of marine resources

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