Along the breakwater on Dallas Road in Victoria, rich kelp forests thrive just below the water’s surface. Brian Timmer, a PhD student at the University of Victoria (UVic), highlighted the success of these kelp forests due to the cold water. However, he noted that other areas in British Columbia are experiencing warming microclimates, leading to the disappearance of once abundant kelp forests.
Timmer spearheaded a recent study at UVic, published in Ecological Applications, that examined historical data on kelp and associated macroalgae communities in the northern Salish Sea. By analyzing maps, scuba surveys, and aerial photos dating back to 1972 and replicating these assessments in 2023, the research team found alarming changes.
The study revealed that 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. Satellite imagery indicated that most of the bull kelp decline occurred between 1972 and 1984.
Contrary to popular belief that recent heatwaves caused the disappearance of B.C.’s bull kelp forests, Timmer’s research suggests that the most significant loss occurred decades earlier. Focusing on a warm water pocket near Comox and Denman Island in the Strait of Georgia, which falls in the top 10% of global ocean warming temperatures, the study noted a concerning trend.
Over the past five decades, sea surface temperatures near Chrome Island lighthouse off Denman Island have increased by 1.66 degrees Celsius, with accelerated warming periods posing a severe threat to kelp populations. Kelp, considered a foundation species and primary producer, plays a crucial role in supporting marine ecosystems by providing food and habitats for various sea creatures.
William Cheung, a UBC professor, emphasized the importance of understanding shifting baselines to inform conservation efforts. UVic researchers observed significant declines in sugar kelp and red bladed algae populations since 1972, attributing the trend to warming waters along the B.C. coast.
To address the decline, Timmer collaborates with the Kelp Rescue Initiative and First Nations to restore kelp forests in the region. Protecting suitable areas and replanting kelp species are crucial steps in combating this environmental challenge.