As a foundational species, giant kelp (Macrocystis pyrifera) is vital to the ecosystem of the temperate, shallow, nearshore waters where it grows. When the kelp flourishes, so do the communities that rely on the fast-growing species for food and shelter.

Giant kelp has proven resilient (so far) to some stressors brought on by climate change, including severe storms and ocean heatwaves — an encouraging development for those interested in the alga’s ability to maintain the legions of fish, invertebrates, mammals and birds that depend on it for their survival. But in a recent study(link is external) published in the journal Oikos, UC Santa Barbara researchers reveal that giant kelp’s ability to take a temperature hit may come at the cost of its nutritional value.

“The nutritional quality, or the amount of nutrients in the kelp tissue seems to be changing,” said the study’s lead author Heili Lowman(link is external), a biogeochemist with the University of Nevada, Reno, who conducted this research as a Ph.D. student in the Department of Ecology, Evolution and Marine Biology at UC Santa Barbara. “We found that those changes were associated or correlated with changing seawater temperatures. From a big-picture standpoint, that’s pretty important because there are a lot of things that rely on kelp as the primary food source.”