New research from the University of Victoria has revealed climate change is severely impacting fragile populations of pink sea urchins off the south coast of Vancouver Island.
The specific pattern of climate change also known as the “Blob,” is a marine heatwave that persisted in the Pacific Ocean off North America from 2013 to 2016.
As a result of these long-standing weather patterns, researchers have found pink sea Urchins are moving into shallower waters as food sources and oxygen levels at lower depths decline due to a warming ocean.
Over the course of seven years, the research team analyzed physicochemical and video imagery data collected at Barkley Canyon Upper Slope within ONC’s NEPTUNE observatory,
The data from NEPTUNE’s Barkley Canyon Upper Slope platform (depth 396 metres) included video cameras, oxygen sensors, and tools that monitor water currents and water physical properties.
By analyzing data before, during, and after the Blob marine heat wave, they found that, on average, the pink urchins moved up to 49 vertical metres into shallower water at a rate of 3.5-metres per year.
Rylan Command UVic Faculty of Science alumni, says as a result of recent heat waves along the BC coast, kelps have been slow to recover, posing a challenge to many species, such as bottom-dwelling sea urchins, which rely on decaying kelp to survive.
“Marine organisms can tolerate variability in dissolved oxygen within a certain range. But as the oxygen minimum zone expands, habitat that was previously suitable may no longer have enough oxygen for some organisms to survive,” he says.
In the long-term, researchers expect that pink urchins will continue to migrate to shallow waters as the northeast pacific oxygen minimum zone expands, and marine heat waves become more frequent as a result of climate change.
According to researchers this adaptation by sea urchins may have long-lasting effects on the wider coastal ecosystem as well as economic impacts.
The pink sea urchin also contributes to the cycling of nutrients in the water by stirring up the ocean floor through bioturbation, as well as feeding on decayed organic materials.
Changes in the density and distribution of this species may directly affect sediment turnover rates and nutrient cycling on the continental margin, with consequences for the surface and coastal productivity of other sea life.