You would think that dropping huge wind turbines into the ocean would scare away all the wildlife.
That’s not what happened in the North Sea. It was the opposite.
After the trauma of the installation, marine life was scarce. But slowly, the organisms started returning. First, it was mussels and barnacles. Then, seagulls claimed the surface sector.
Finally, seals arrived and thrived in the superb hunting conditions.
What drew these ocean predators to this specific man-made island?
How nature moved in to claim human infrastructure
We know how brutal the North Sea environment is with its wild weather and water currents.
The open ocean offers minimal shelter for marine life.
But when humans dropped brand-new structures into the waves, nature moved in.
Over a relatively short space of time, the structures transformed in distinct stages.
The pioneers underwater are microscopic larvae that settled on the frames. These grew into thick colonies of barnacles and mussels.
It’s the solid anchor points that changed the game.
At the surface, the flat floating platforms offered a dry and stable spot to rest in the wide open sea. Seagulls were thrilled with the artificial island life.
The industrial sites became sanctuaries of thriving sea life in just months.
The explosion of life under the waves couldn’t remain covert for long. Larger animals were attracted by the commotion and moved in to exploit the situation.
How did the local sea life clock on to this brand-new territory so quickly?
Offshore wind platforms have something seals want
Researchers wanted to know exactly what was attracting seals to two specific North Sea wind farms. These were Alpha Venus near Borkum Island, Germany’s first ever wind farm, and Sheringham Shoal off the coast of England.
Dr. Deborah Russell and a team of researchers from the University of St. Andrews decided to figure it out.
Tracking two kinds of seals, namely harbor and gray seals, took some doing. First, they were caught with specialized nets.
Then they had GPS units attached to the fur on the back of their necks. The device attaches with a safe adhesive that eventually releases itself.
Three distinct behaviors were modeled from the data: resting, foraging, and traveling.
There was nothing ambiguous in the results: seals were actively changing their routes to visit the man-made installations.
The structures function like artificial reefs. And marine wildlife has a fondness for solid objects, foreign or not.
There’s an ongoing debate in the marine biology world. Do these sites encourage population growth or simply concentrate fish in one area?
Whatever the case, seals think it’s a winning situation all around, according to Ocean Oculus.
But what is it about these specific offshore farms that makes them so irresistable to these apex predators?
The unintended positive consequences of green energy farming
The question at the heart of the situation is what features of the turbine installations attracted the marine life.
The physics of the ocean has a lot to do with it, says the study “Offshore wind farms become magnets for hungry seals,” published in Science.
When humans drop infrastructure into the ocean, it acts like an anchor in a desert. The open ocean is mostly empty space.
Life can take root on something solid, starting with the mussel and barnacle biofouling.
A living underwater wall of food
Small fish will soon be attracted by the buffet and plants and smaller organisms. Naturally, bigger fish follow, and so on.
This brings us back to the St. Andrews study of Alpha Ventus and Sheringham Shoal. The data is clear that these clean energy sites act as artificial reefs.
They concentrate the entire food chain in a single grid, and the smart seals worked it out.
As we gather more renewable energy at sea, we are shifting marine ecosystems. Are we saving these predators, or just making them lazy hunters?