Along Dallas Road in Victoria, near the breakwater, vibrant kelp forests thrive just below the water’s surface due to the consistently cold water conditions. However, in various parts of British Columbia, there are localized areas of warming known as microclimates that have led to the disappearance of once abundant kelp forests. This revelation comes from a recent study conducted by Brian Timmer, a PhD student at the University of Victoria, and his research team, as published in Ecological Applications.
Utilizing historical data dating back to 1972, including maps, scuba surveys, and aerial photos, the team examined the status of kelp and associated macroalgae communities in the northern Salish Sea. In 2023, they revisited these locations to make direct comparisons with the past imagery.
The study revealed that the expansive bull kelp forests that used to cover over 5.5 million square meters in the northern Salish Sea, particularly around the Comox and Denman Island area, have vanished entirely. This loss contrasts starkly with the previous baseline estimate established around 2000, which was only a fraction of the actual coverage. Satellite data indicated that the majority of the bull kelp decline occurred rapidly between 1972 and 1984.
Contrary to popular belief linking recent heatwaves to the disappearance of B.C.’s bull kelp forests, Timmer’s research indicates that the most significant loss occurred several decades ago. The study pinpointed a warm water pocket near Comox and Denman Island within the Strait of Georgia, showcasing a top 10% increase in global ocean warming temperatures.
Sea surface temperatures near Chrome Island lighthouse have risen by 1.66 degrees Celsius over the past 50 years, with accelerated warming periods posing the greatest threat to kelp populations. Kelp, being a foundation species and primary producer, plays a crucial role in marine ecosystems by providing food and habitats for various sea creatures.
The decline in kelp populations, particularly sugar kelp and red bladed algae, is attributed to the warming waters along B.C.’s coast, according to the University of Victoria researchers. William Cheung, a professor at the University of British Columbia, emphasized the importance of establishing accurate baselines to inform conservation efforts and climate adaptations.
Timmer collaborates with the Kelp Rescue Initiative and First Nations to restore kelp forests in British Columbia by identifying suitable habitats for replanting kelp species. This initiative aims to protect and preserve critical marine ecosystems for future generations.