Chalk and sand seabed off the Sussex coast, about 60 feet down, flat in every direction.
A steel monopile comes out of it carrying a wind turbine, one of more than a hundred on this site.
Around the base of this particular one sits a heap of pale concrete blocks, roughly 1,900 short tons of them.
They were not put there for the wildlife, whatever the headlines say.
They went in because the seabed was leaving.
The hole was 6 to 10 feet deep.
Why a current digs a hole around a pile it cannot move
Water flowing past a vertical cylinder does not simply part and rejoin. It wraps around the front and rolls into a horseshoe shaped vortex at the base.
That vortex is faster than the surrounding flow, and faster water lifts more sediment, so the sand immediately around the pile leaves first.
The hole that forms is self deepening for a while. A deeper pit exposes more pile, which strengthens the vortex, which digs further.
Left alone it changes the structure underneath the machine. The buried length shortens, the point where the pile is effectively fixed moves downward, and the whole tower’s natural frequency drifts.
Frequency drift is the part that matters, because a turbine tower is tuned to avoid resonating with its own rotor, and a moving fixity point walks it toward the thing it was designed to dodge.
The current takes the sand. The tower loses its tuning.
What went in and what the coverage gets wrong
The usual answer is rock armour, quarried stone dropped around the base until the flow gives up. It works and it is ecologically inert.
Here the fix was about 75,100 cast blocks instead, and they are not rock. They are concrete, made from 98 percent recycled material and free of plastic, cast in Cornwall.
They are also not all hollow, which is the detail most reports flatten. Roughly half the mix is solid cubes about 6 inches across.
The rest are larger, around 14 inches, and those carry internal passageways and chambers running through them.
That mix is the design rather than a compromise. The small solid blocks give the mass and the packing that actually stops the scour, and the large hollow ones supply the holes for anything that wants to live in them.
Small ones hold the seabed. Large ones hold the animals.
How the blocks got down there
Placement used a fall pipe, a long tube lowered from a vessel so material lands where it is aimed rather than scattering through 60 feet of moving water.
That matters here because the target is a pit a few yards across, not a general apron.
The installation ran in October of last year, after a trial that put down about 23 short tons to see how the blocks behaved on the way down and where they settled.
Scaling from that to roughly 1,900 short tons is a factor of more than eighty on a single rehearsal.
The turbine chosen was the one with the problem, not the one most convenient for divers.
The trial was 23 tons. The job was eighty times that.
What is actually known about the marine life so far
This is where the story needs slowing down, because the claim in circulation is running ahead of the evidence.
Ecological surveys on this installation are scheduled for this year, then 2028, then 2030. The first of them has not produced a published result.
So the honest position is that the cubes are in place, they are performing an engineering function, and whether starfish, brown crab and oysters take to them is an open question with a survey date attached.
The expectation is reasonable. Hard structure in a sandy plain does attract animals that need somewhere to hide, and that is well established.
Dropped steel does it too, as New York found when it sank subway cars and counted 400 times more sea life on them.
The cube counts, the two sizes and the survey years are set out by the developer.
The blocks are installed. The biology is unmeasured.
Why the answer may not come from the cubes at all
There is a confounder sitting over the whole experiment and it is worth naming.
Bottom trawling is generally excluded from the water between turbines, for the practical reason that nets and buried cables do not mix.
That exclusion alone changes a seabed. Anything that grows on the bottom gets left standing instead of being scraped off a few times a year.
So a survey in 2028 finding more life around this turbine has two candidate explanations, and separating the cubes from the absence of a trawl needs a control that nobody has described.
The same exclusion has already turned up shark and ray traces in Dutch farms where trawling stopped.
The pilot, the partners and the wind farm are described by a wind title.
A scour pit got filled properly, and the nature headline is a forecast rather than a finding.
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