Trial with eelgrass in the Wadden Sea is unexpectedly successful

A trial with the planting of eelgrass in the Wadden Sea is unexpectedly successful. Scientists speak of a breakthrough, because the plants spontaneously spread to (far) outside the trial area at Griend, between Harlingen and Vlieland and Terschelling.

“The field is now expanding. Also outside our trial plots”, says Laura Govers of the University of Groningen at Omrop Fryslรขn. “That’s a fantastic development. We now want to see if it can sustain itself without sowing extra.”

Scientists have been trying for years to get the eelgrass back into the Wadden Sea. The plant used to be omnipresent, but disappeared due to plant diseases after the construction of the Afsluitdijk. The plant is still growing in the German and Danish Wadden area

Injecting with a kit gun

A number of years ago, Dutch scientists began to take seed from Germany to experiment at Griend, the uninhabited island around which the ferry to Terschelling and Vlieland sails with a wide bow. Earlier, some success was achieved in injecting the seed into the soil with a kind of kit gun. The processing of seed with copper sulphate also seemed to have a positive effect.

But last year it suddenly goes really fast. In spring the plant appeared to have spontaneously sown itself to an area of 100 hectares. now it is over 170 hectares. There are now about 100 thousand plants growing at Griend’s and that makes it by far the largest eelgrass field in the Dutch part of the Wadden Sea.

Prawns stick

The project will run for another year. During that time, the researchers want to make the ‘plots’ that are sown larger. “What we also want here, is small eelgrass. Large eelgrass, what we have now, is one year. So that disappears every winter. It retains a lot of silt, but in winter it releases it again because the plants die. If you have a lot of small eelgrass, the mudflats can also catch more silt and are more resistant to rising sea levels. That’s a long-term effect”, says Govers.