Scientists are diving into Monterey Bay every week to watch kelp face down a “super El Niño”

UC Santa Cruz researchers are diving into Monterey Bay’s kelp forests every week this fall to watch, in real time, how giant kelp holds up against a forecasted “super El Niño.” The effort is led by Joshua Smith, an assistant professor of ecology and evolutionary biology who runs the campus’s Nearshore Ecology Research Group, working alongside a graduate student, three undergraduates, and partners at the California Ocean Protection Council, the Seaver Institute, and Monterey Bay National Marine Sanctuary. The dives began in September 2026, as sea surface temperatures climbed toward levels not seen since the marine heatwave of 2014 to 2016, and the team plans to keep diving through the peak of the warm event and into the recovery period that follows.

The urgency comes from what happened last time Pacific waters warmed this much. During the 2014-2016 heatwave, warm water suppressed kelp growth and nutrient availability along much of the West Coast, and sea urchin populations that would normally be kept in check exploded, grazing entire kelp forests down to bare rock in what ecologists call urchin barrens. Northern California lost the vast majority of its bull kelp canopy and still has not recovered. Giant kelp forests like the ones in Monterey Bay are separately among the most productive ecosystems on Earth, supporting thousands of species and underpinning fisheries and kelp-derived products that Smith’s team estimates contribute roughly $500 billion a year to the global economy, so a repeat collapse would ripple well beyond the kelp itself.

What makes this project different from most kelp research is timing: rather than documenting a collapse after the fact, the team is trying to catch one as it unfolds, or catch its absence. On weekly dives, researchers measure kelp growth and canopy cover, track water temperature and nutrient levels, and watch for the early signs of urchin population shifts that have preceded past die-offs, generating a dataset that updates in near real time instead of arriving in a paper years later. Smith frames the project’s value simply: for once, researchers get to watch a shift happen in real time, rather than reconstruct one years later from what’s left behind.

Whether this El Niño repeats the 2014-2016 story is still an open question, and part of the point of the project is that no one yet knows how a mature, actively monitored kelp forest responds to this kind of acute warming when scientists are watching from the very first week. The team’s monitoring will continue through the warm event and into the water’s return to normal temperatures, when they hope to document whether Monterey Bay’s kelp rebounds on its own or needs help. For a marine sanctuary that has already invested heavily in kelp restoration, the answer could shape how, and how urgently, that work continues in the years ahead.

Further reading: UC Santa Cruz News, “UC Santa Cruz researchers launch real-time study on kelp resilience as a super El Niño unfolds” (2026).