Once oil rigs, wind turbines and other large ocean installations outlive their usefulness, it is typically mandated that they be removed from the site. Yet a team of international researchers is appealing to environmental officials to keep the large installations in place because the structures serve another vital function as artificial reefs.
Publishing an article in the international journal Frontiers in Ecology and the Environment, the research team found through the lens of a submerged camera that an aged oil rig no longer in use is now home to flatfish, cod and a variety of bottom fauna — all of which are not usually found in the section of the North Sea where the team conducted research.
"We also see many more porpoises around oil rigs than in the surrounding sea," said senior researcher Jonas Teilmann from Aarhus University. "It's easy to understand why the porpoises enjoy the area. One can't throw a fish hook without catching one of the many cod around the legs of the oil rig."
With a 20 to 30 year presence at sea, many of these installations — the bars, concrete bricks, tubes and other submerged material — become environments for adhering plants and animals, according to the researchers. However, it is generally common practice the world over to remove such installations as soon as they outlive their usefulness.
Now, the team, made up of over 30 international researchers, is asking environmental officials to reconsider the practice of decommissioning such structures.
"We have observed a significantly increased biodiversity around the old facilities and encourage the authorities to consider, in each individual case, whether an exemption from the demand for removal can be granted. When making the assessment, the environmental conditions must, of course, be of sufficient quality," explained Teilmann.
With over 7,000 oil and gas platforms and roughly 10,000 to 20,000 wind turbines on the verge of eventual removal, the team is urging politicians and officials all over the world to temporarily halt the decommissioning of such structures.
“By leaving the rig in place, we may ensure greater biodiversity in the sea. The physical structures also ensure that the areas will not be trawled. The heavy trawls turn the seabed into a uniform desert with poor biodiversity," said Teilmann.