Giant Kelp’s Survival Could Depend On Where It’s From

Nov 18, 2019

Researcher Jordan Hollarsmith arrived at UC Davis as a graduate fellow in 2014 with the main goal of studying kelp forests in Northern California. 


But then the region was hit with a marine heatwave known as “the blob.”

“All the kelp in Northern California felt like it disappeared rapidly,” Hollarsmith recalls. “So that made me change my plans, clearly, because the system I was going to study was no longer there and it wasn't coming back.”

Hollarsmith took to the lab. Her research — recently published in Journal of Experimental Marine Biology and Ecology — show that giant kelp from Northern California isn’t as resilient to external stressors, like heat or acidity, as the same species from Southern California or Chile.

“We could tell that [giant kelp] are growing in some conditions in Southern California and not in Northern California, but it hadn't been tested in a lab yet. This was the first step to show that something is causing differences in these populations. For some reason, they are more robust. It opens exciting questions for what is driving that difference.”

The answer, she says, could lie in genetics.

“It could be that because the adults were exposed to higher temperatures in the water and so they preconditioned the offspring to survive under them,” Hollarsmith says. “That's something called transgenerational plasticity, where what the parents survive affects the offspring.”

That could mean that giant kelp forests in warmer climates might have a higher survival rate as temperatures across the world increase with global warming. If kelp populations continue to disappear off Northern California’s coast, other organisms will likely go along with them.

“These giant forests of algae provide habitat for so many fish that humans rely on both economically and culturally,” Hollarsmith says.

Hollarsmith is now studying bull kelp, a different species that is also struggling to survive off Northern California’s coast.