Off the coast of Northern California, an underwater ecosystem collapse has been unfolding largely out of public view. This mini documentary tackles a fascinating ecological cascade: the disappearance of bull kelp forests and their replacement by lifeless "urchin barrens" — vast stretches of seafloor stripped bare by exploding populations of purple sea urchins.

The story hinges on a keystone species most people have never heard of: the sunflower sea star, once one of the largest and most voracious predators on the Pacific coast. A devastating sea star wasting disease wiped out roughly 90% of the population starting around 2013, removing the main check on urchin numbers. With no predators, urchins multiplied and ate the kelp down to the rock. Without kelp, the entire food web that depended on it — abalone, rockfish, otters — began to unravel.

What makes this worth watching is how clearly it connects the dots between marine disease, predator-prey dynamics, and ecosystem collapse. It's a textbook example of a trophic cascade, the kind of concept ecology students read about but rarely get to see illustrated with real footage and real stakes. The video also touches on restoration efforts, including urchin culling and sunflower star captive breeding programs.

Project Urchin has zero subscribers, which is a shame — this is exactly the kind of accessible, region-specific science communication that bigger nature channels tend to skip over.