Photo by Alan David Robb
A sweeping new scientific review has laid bare the long-lasting and system-wide impacts of the 2014–2016 marine heat wave that engulfed the northeast Pacific Ocean. Described by researchers as the most extensive assessment of its kind, the study reveals how rising ocean temperatures are not only bleaching corals and warming waters—but fundamentally rewriting marine ecosystems from the seafloor to the open ocean.
Led by researchers from the University of Victoria’s Baum Lab, the study synthesises hundreds of reports and peer-reviewed studies to tell the story of a three-year heat wave that pushed ocean temperatures up to 6°C above average. As reported by Phys.org, the event decimated keystone species, collapsed kelp forests, disrupted whale migrations, and sent over 240 marine species into new and often unstable territory.
Kelp forests and seagrass beds—critical habitats for biodiversity and coastal stability—were among the hardest hit. The disappearance of sunflower sea stars (Pycnopodia helianthoides), one of the kelp forest’s top predators, triggered unchecked urchin grazing, further accelerating kelp collapse. In their place, fast-growing turf algae took hold, reducing the ecosystem’s complexity and shifting food web dynamics.
As warm waters spread, animals moved. Whales, sea slugs, and dolphins were recorded far north of their usual ranges. The northern right whale dolphin and the sea slug Placida cremoniana, for instance, were both observed more than 1,000 km beyond their known habitats. At the same time, food sources became scarce. Forage fish such as anchovies and sardines declined in both abundance and nutritional value—placing enormous stress on seabirds, marine mammals, and the fisheries that depend on them.
Offshore productivity dropped. Seabird and whale strandings surged. Commercial fisheries in British Columbia, Washington, and California collapsed in some areas, with the economic toll of the heat wave estimated in the hundreds of millions of dollars. The review makes clear that these weren’t isolated impacts—they were part of a tightly connected ecological unravelling.
Perhaps most sobering is the implication that this is only the beginning. “As heat waves become more frequent and intense under climate change, the 2014-16 Northeast Pacific marine heat wave provides a critical example of how climate change is impacting ocean life, and how our future oceans may look,” said Baum. The event—nicknamed “The Blob”—now serves as a warning for what climate-changed oceans could look like on a global scale.
The full review, published in Oceanography and Marine Biology: An Annual Review, urges a shift toward ecosystem-based, adaptive marine conservation. That means kelp restoration, early warning systems, and management that accounts for the increasing instability of marine systems—not just preserving what exists, but preparing for what’s to come.