[This feature originally appeared in our April 2017 Issue, “Evolution,” on newsstands and available for download now.]

On wind-torn days from San Diego to Crescent City, California surfers have always had an unsung ally in kelp forests. Those large accumulations of kelp you see floating outside the lineup have the ability to groom and comb waves as they make their way toward shore, which is why those of us obsessed with riding clean, glassy lines tend to flock to kelp-protected breaks on blustery days.

But surfers aren't the only creatures reliant on these forests. Kelp supplies food for herbivorous sea creatures, prevents coastal erosion, and provides protection for fish and other marine life against larger predators. Kelp even produces alginate, a carbohydrate used to thicken toothpaste and, more importantly, that glorious tubful of Ben & Jerry's ice cream you probably have sitting in your freezer right now.

Unfortunately, this past century hasn't been kind to many of our brown-leaved friends. In spots around Orange and Los Angeles counties, giant kelp have declined by 75 percent over the last 100 years, mainly due to things like coastal development, sewage discharge, power plant effluent, and the overfishing of sea urchin predators (a sea urchin diet comprises mainly kelp, so when predators don't keep the number of sea urchins in check, those spiny devils go crazy and wolf down healthy kelp forests).

Remember the cult-classic sci-fi movie The Blob, in which an amorphous, amoeba-like creature descends to Earth and swallows everything in its path? That's pretty much what kelp in Northern California is facing at the moment. A couple of years ago, a viral outbreak killed a huge amount of sea stars (the primary sea urchin predator in Northern California), which allowed the sea urchin population to run amok on the bull kelp forests in Sonoma, Mendocino, and Humboldt counties. If you were to venture out into the frigid waters of these areas and look beneath the surface, you'd see spiny purple urchins crawling through an aquatic graveyard of barren stalks of kelp.

"We saw more than 60 times the numbers of purple urchins than we've ever seen before," explains Cynthia Catton, an environmental scientist with the California Department of Fish and Wildlife. "We've been surveying the reefs since the 1990s and we've never seen anything near this number. In some places it was 100 times the amount of normal sea urchins."

Kelp forests in parts of Southern California dealt with a similar horror story in the past. Storm-water runoff and sea urchins plowed down forests in Palos Verdes and Malibu, but thanks to organizations like Los Angeles Waterkeeper and The Bay Foundation in Santa Monica, water quality has improved, the urchins are under control, and the kelp has been reforested. But some California kelp beds are facing a new threat as well.

In addition to battling pollution and booming predator populations, kelp is locked in a fight for resources with an invasive alga called Sargassum horneri (try reading that aloud while keeping a straight face). The oddly named insurgent came over in a transoceanic crossing of Korean and Japanese shipping containers in 2003, and it spread up and down the coast. You've probably seen the brown, lace-like organism floating around the lineup or stuck in your hair. Now it's competing with kelp for space and nutrients and has spread like wildfire in places like Catalina Island and Crystal Cove.

According to L.A. Waterkeeper dive program manager Ian Jacobson, these threats may diminish California kelp forests, but environmental organizations like his will continue fighting to preserve local kelp beds, and it's unlikely that we'll lose our lineup-grooming pals completely. And that's good news for surfers, because if the natural balance of the ocean gets that out of whack, then we'll probably have much bigger concerns than whether or not our favorite reefbreak stays glassy on onshore days.

[Title Photo: Photo by Chachi]