Near the shores of Dallas Road in Victoria, diverse kelp forests thrive just below the water’s surface due to the consistently cold water, as explained by Brian Timmer, a PhD student at the University of Victoria (UVic). However, in various parts of British Columbia, specific areas are experiencing localized warming known as microclimates, causing the disappearance of once abundant kelp forests.
A recent study led by Timmer from UVic and published in Ecological Applications analyzed historical data on kelp and macroalgae communities in the northern Salish Sea dating back to 1972 through maps, scuba surveys, and aerial photographs. The team replicated these studies in 2023 to make direct comparisons.
The research revealed that extensive bull kelp forests once covered over 5.5 million square meters of the northern Salish Sea around the Comox and Denman Island region. This amount was ten times higher than the previously accepted baseline set around 2000. Sadly, none of these kelp forests exist today, with satellite imagery indicating a significant loss of bull kelp between 1972 and 1984.
Contrary to popular belief linking recent heatwaves to the disappearance of B.C.’s bull kelp forests, Timmer’s study suggests that the most substantial losses occurred decades earlier. The study highlighted a warm water pocket near Comox and Denman Island in the Strait of Georgia, representing one of the top 10% of global ocean warming temperatures.
Over the last 50 years, sea surface temperatures at the Chrome Island lighthouse, off Denman Island’s southern tip, have risen by 0.25 degrees Celsius per decade, totaling a 1.66-degree Celsius increase. Scientists emphasize that accelerated warming periods are detrimental to kelp populations.
Kelp, deemed a crucial foundation species and primary producer, plays a vital role in marine ecosystems by providing food and habitats for numerous sea creatures. Timmer’s research at UVic indicated significant declines in sugar kelp and red bladed algae populations since 1972, attributing this decline to the warming waters along the B.C. coast.
William Cheung, a professor at the University of British Columbia (UBC), emphasized the importance of establishing accurate baselines to understand environmental trends properly for effective conservation and climate adaptation strategies. Timmer now collaborates with the Kelp Rescue Initiative and local First Nations to restore kelp forests in British Columbia, aiming to protect suitable areas and reintroduce kelp species for long-term habitat restoration.
