No permit is required. At the edge of a low tidepool, a colony of tube-dwelling worms has created a new mound of calcareous tubes and cemented sand. Bioconstruction adds structure and mass to rocky shores. The raised mounds that mark colonies are rock-like to the touch.
Below, at the edge of the same small pool, more bioconstruction. I imagine these mounds are the work of Dodecaceria, but there are alternatives, other colonial polychaete builders.
Lest you think the construction takes place on the sheltered edges of tranquil pools, behold the scene below. The view from the pool’s seaward rim reveals the backdrop within which the worms do their work.
It’s a wonder tiny worms can build their mounds in such a high-energy, erosive environment. But then again, we see plants, algae, mussels, and barnacles making a living on the rocks and each other in the full force of the surf. So in that sense, Dodecaceria isn’t exceptional.
I updated this post on November 3, 2022.
theoutershores 
Very unique and interesting！Beautiful photo. Thank you so much for sharing. ：）
Thank you Amy, I couldn’t have done it without you.
🙂 🙂 See you soon!
Wow. VERY unique. Well done.
One thing I noticed after I posted this is that while the worms build the reef, the urchins erode it. They scour out depressions in the rock. You can see it, to an extent, in the images. There’s balance for you! Thank you for your nice words.
Your description or lesson is truly enhanced by the very artistically presented images. Super post! Truly.
It’s a mystery to me how to balance photo(s) v. words on photo challenges, so I appreciate your feedback. Thanks!
I’m with Gunta, you’ve found the perfect blend. Very interesting post about a unique construction project!
I’ll take any tip I can get! Seriously, I appreciate you having a look. Thank you!
Wonderful 🙂
Thanks for taking the time to mention it. I appreciate it a lot.
You’re welcome 🙂
Amazing. Do the Dodecaria (or other inhabitants of this zone) use tidal power for various activities?