Near the Dallas Road breakwater in Victoria, the waters are abundant with lush kelp forests just below the surface. Brian Timmer, a PhD student at the University of Victoria (UVic), mentioned that these kelp forests thrive due to the consistently cold water. However, in various parts of British Columbia, there are localized areas of warming known as microclimates, where kelp forests have disappeared over time.
A recent study conducted by Timmer from UVic, published in Ecological Applications, utilized historical data dating back to 1972 to analyze the decline of kelp and associated macroalgae communities in the northern Salish Sea. The research team compared past images and surveys with those from 2023 to assess the changes over time.
The study revealed that once expansive bull kelp forests, covering over 5.5 million square meters in the northern Salish Sea around the Comox and Denman Island region, have vanished. This loss is ten times greater than the previously established baseline around 2000. Notably, satellite imagery indicated that the majority of the bull kelp decline occurred between 1972 and 1984.
Contrary to popular belief linking recent heatwaves, like the “Blob” heatwave from 2014 to 2016, to the disappearance of B.C.’s bull kelp forests, Timmer’s research suggests that the most significant losses occurred decades earlier. The study focused on a warm water pocket near Comox and Denman Island, within the top 10% of global ocean warming temperatures.
Over the past five decades, sea surface temperatures near Chrome Island lighthouse off Denman Island have risen by 0.25°C per decade, totaling a 1.66°C increase. Accelerated warming periods are identified as the primary cause of damage to kelp populations.
Kelp, recognized as a foundation species and primary producer, plays a crucial role in supporting marine life by offering food and habitats for various sea creatures. Timmer’s study emphasized that the decline in bull kelp and other algae species is likely due to the warming coastal waters in British Columbia.
William Cheung, a professor at the University of British Columbia (UBC), highlighted the importance of establishing accurate baselines to understand ecological trends properly for conservation and climate adaptation efforts. Cheung suggested that historical baselines may differ significantly from current perceptions, leading to a shifting baseline issue.
Timmer collaborates with the Kelp Rescue Initiative and First Nations to restore kelp forests in British Columbia by identifying suitable habitats and replanting kelp species. Protecting these areas is crucial in combating the decline of kelp populations and preserving marine ecosystems for future generations.
