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 cold water. However, in various regions of British Columbia, such as the Nootka and Esperanza inlets and the Barkley Sound, there are warming microclimates that have led to the disappearance of once dense kelp forests.
According to a recent study led by Timmer from UVic and published in Ecological Applications, historical data on kelp and associated macroalgae communities in the northern Salish Sea were gathered using maps, scuba surveys, and aerial photos dating back to 1972. In 2023, the research team replicated these surveys to make direct comparisons.
The study revealed that expansive bull kelp forests, covering over 5.5 million square meters in the northern Salish Sea near the Comox and Denman Island region, have vanished. This is ten times more than the previously accepted baseline established around 2000. Satellite imagery indicates that the majority of bull kelp loss occurred between 1972 and 1984.
While previous research attributed the disappearance of B.C.’s bull kelp forests to recent heatwaves, Timmer’s study suggests that the most significant losses occurred decades earlier. The study focused on a warm water pocket within the Strait of Georgia near Comox and Denman Island, which falls within the top 10% of global ocean warming temperatures.
Over the past 50 years, sea surface temperatures at the Chrome Island lighthouse, off Denman Island’s southern tip, have increased by 0.25°C per decade, totaling a 1.66°C rise. Experts warn that accelerated warming periods are particularly detrimental to kelp populations.
Kelp is considered a foundation species and primary producer crucial for marine ecosystems, offering food and habitats for various sea creatures. The UVic study emphasizes the importance of establishing accurate baselines to inform conservation efforts and climate adaptations.
Researchers observed a significant decline in sugar kelp and red bladed algae since 1972, attributing it to warming waters along B.C.’s coast. Timmer collaborates with the Kelp Rescue Initiative and First Nations to restore kelp forests by identifying suitable areas for replanting kelp species.
Cheung, a professor at the University of British Columbia, highlighted the urgency of protecting these habitats to prevent further losses of kelp forests in B.C.
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