Maybe there's hope for 'the dead fjord': Come with the researchers beneath the surface

At the bottom of the sandy shore, it is clearly visible the blue mussels.

Large areas in the green fjord water are covered by mussel banks. Here and there, a pale starfish emerges, spreads its arms, and a small fish swims by. On the mussel beds, the curled seaweed, sugar kelp, grows.

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> I want far from the cold fjord for death

> Timi Løvholt Banke, ph.d.-student at Biological Institute, University of Southern Denmark

Recently, DR was with a group of researchers from the Biological Institute at the University of Southern Denmark on a diving trip to check how it is going on the bottom of Vejle Fjord, located a few miles out in the fjord.

As part of the project Sund Vejle Fjord, they are working to restore a part of the nature in the fjord, among other things by planting mussel beds.

And what the researchers could see on the fjord bottom, is good news, says Timi Løvholt Banke, who is a ph.d.-student at the Biological Institute at the University of Southern Denmark. Mussel beds look stable, and the seaweed, which grows on them, is a really good sign, he says:

- In fact, there is enough light for them to grow there now.

- We get a little more structure and life there, because the large seaweed beds provide enormous good hiding places for marine life.

In the clip here, Timi Løvholt Banke shows the seaweed, which grows on the mussel beds:

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The fjord is far from dead

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Vejle Fjord has been called dead ( https://www.dr.dk/news/domestic/death-announcement-vejle-fjord-is-dead-and-will-be-buried-within-weeks-with-a-priest-present ) , and last year, the fjord was "buried" at a memorial service ( https://www.dr.dk/news/domestic/vejle-fjord-was-buried-by-hundreds-of-people ) . For marine and plant life in the fjord, the pressure comes from algae growth and oxygen depletion ( https://www.dr.dk/news/domestic/oxygen-depletion-killed-60-percent-of-mussels-on-an-island-in-vejle-fjord ) .

But if you ask Timi Løvholt Banke, there is hope for the hard-pressed fjord.

- I want far from the cold fjord for death. It has not been good, but it is not dead, he emphasizes.

The research project Sund Vejle Fjord has been in progress since 2020, and here they are trying to restore a part of the nature in the fjord among other things by planting eelgrass, establishing stone reefs and planting mussel beds.

According to Timi Løvholt Banke, the project is the largest marine nature restoration project in Denmark, and the researchers can see that it works.

- We can clearly see that it makes a difference exactly where we restore nature. The marine life comes back quickly. So definitely not dead. One just has to give it a hand to come back, he says.

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Stable mussel beds

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Researchers from the University of Southern Denmark have, in connection with the project, planted mussel beds in Vejle Fjord since 2020. Today, there are 52 hectares of mussels in the fjord.

Mussels do many good things for the nutrient-poor fjord, explains Timi Løvholt Banke. For one thing, they live by eating the algae in the fjord.

- They filter the water. A part of their life is to eat the algae from the water, exactly what is contributing to making the water cloudy and making the fjord in a bad condition, he says.

Mussel beds help biodiversity as well, because they create holes, cracks and small tunnels, which are habitats for crustaceans and fish, explains Timi Løvholt Banke.

Here are the mussel beds planted in Vejle Fjord. The mussel beds cover a total area of 52 hectares, which is almost 2000 tons. (Photo: © Biological Institute, University of Southern Denmark)

The researchers keep a close eye on how much the mussel beds grow. They use a metal ring, which measures a meter in diameter, place the ring on the bottom and see how much of the area in the ring, which is covered by mussels, explains Timi Løvholt Banke.

- And so we do it often enough, and then we have an idea of how the condition of the bank is. Are there more mussels, is there a decline or is it stable, in relation to how much is covered by living mussels, and have there been changes, since we last visited it.

- It sounds very simple, but the human eye is actually really good at evaluating these things, he says.

The preliminary status surveys of the mussel beds in the fjord show good signs.

- The banks are stable since last.

- We looked at them in the fall, and we have not had any significant winter losses, says Timi Løvholt Banke.

In the clip here, you can see how it works when the researchers measure the mussel beds:

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Nature restoration cannot stand alone

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A report from 2022 ( https://www.vejleaadalogfjord.dk/sites/vejleaadalogfjord.dk/files/2023-06/Modelaktivitet%20i%20Sund%20Vejle%20Fjord.pdf ) , which researchers from the Biological Institute at the University of Southern Denmark are behind, shows that more than half of the nutrient input to Vejle Fjord, which primarily flows into the fjord via Vejle River, comes from agriculture, including a smaller part, which comes from nature and is not due to human pollution.

According to the researchers, the pollution contributes to increasing algae growth in the fjord and reducing the ecological condition.

Even though nature restoration in Vejle Fjord seems to work, it does not put a stop to the real source of the problems, says Christian Fromberg, who is campaign leader for agriculture, forest and nature in Greenpeace:

- We think it is a fantastic effort that has been going on in Vejle for many years. A big thank you to Sund Vejle Fjord and the other initiatives there.

- It cannot stand alone. There is also a need for stopping the pollution of the fjord. Otherwise, we will just end up with a large oxygen depletion, which takes the life of the eelgrass and the mussels, which have been planted.

Biologist in the Danish Angling Association Kaare Ebert is excited about the results in the project Sund Vejle Fjord.

- It shows that despite the fact that the fjord has been bad and is under pressure, one can already begin the process of creating life again.

But if nature restoration is not to be wasted work, then he, too, thinks it depends on whether one can reduce the nutrient input to the fjord.

- Because if we get an oxygen depletion in the summer, and everything dies, then one has wasted at least something of it. And it is of course important to limit the loss of nitrogen primarily, but also phosphorus here in Vejle Fjord.

© Asger Ladefoged/Ritzau Scanpix

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Project Sund Vejle Fjord

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The project Sund Vejle Fjord is financed by Velux Foundation and Vejle Municipality.

Velux Foundation has recently granted money for the project to continue until further notice up to 2029. The project Sund Vejle Fjord consists of the following interventions:

*1* : Scientific studies of the fjord's problems

*2* : Marine nature restoration with planting of eelgrass, laying of mussel beds, fishing of crabs and establishment of new stone reefs

*3* : Mobilization and involvement of local citizens, associations and researchers

*4* : Communication about the fjord's condition and progress, among other things in films and exhibitions

Source: Vejle Municipality

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It is not a solution, it is a help

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According to Timi Løvholt Banke, the researchers choose their nature restoration areas with care exactly to avoid the areas where oxygen depletion can become a problem.

At the same time, he agrees that nature restoration cannot stand alone.

- We are forced to reduce the nutrient input from the countryside. That is what has made it bad to start with. If we do not remove it, then it will probably remain bad.

- But by restoring, we can help the system to turn. We can help with pushing it in the right direction. It is not a solution, it is a help, emphasizes Timi Løvholt Banke.

Warning: This article was translated by a Large Language Model, in case of doubt, you can always visit the original source.