Hard substrates

Gilson sample

The bed of the Belgian part of the North Sea is mainly made up of sand. Pebbles are found in a number of places between the sand banks and in the trenches. We are carrying out research into the creatures which live on these so-called gravel beds. Historical data that were gathered more than 100 years ago by Prof. Gustave Gilson, the Belgian pioneer of modern oceanography, show us that these areas are home to a particularly diverse community, but these days very little remains of them. The zones are intensively fished, which means the often fragile fauna which lives on the pebbles, is damaged and destroyed. Soon fishing will no longer be permitted in a part of the gravel beds. We will then investigate whether the communities can re-establish themselves and return to their historic biodiversity levels.

Hard substrate - Credit Alain Norro

Alongside this we are investigating life on so-called artificial hard substrates. There are increasing numbers of hard substrates such as harbour walls and groynes (or breakwaters) in the sea. Since 2008 new artificial hard substrates have been built in the sea, wind turbines. At the moment there are around 100 wind turbines in the sea, but in a number of years this figure will have risen to around 600.  This is why it is important to understand how these structures influence the functioning of the marine ecosystem.

Our research boat RV Belgica travels the wind farm to observe the creatures that live on the foundations. We also study the creatures who live among the stones that protect the foundations from erosion. Divers are then taken to the wind turbines in a small boat and there they take, at different depths, samples of the organisms living on the foundations and the stones surrounding them. The foundations are also filmed.

The communities on the wind turbines are fundamentally different from the creatures that live in the sandy seabed, which explains how their role within and their influence on the marine environment can be different. In this study we are particularly focusing on non-indigenous species.

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