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 populations thrive due to the consistently cold water in the area. However, as you move to different regions in British Columbia, such as Nootka and Esperanza inlets and Barkley Sound, there are localized areas experiencing warming trends, known as microclimates.
A recent study led by Timmer from UVic, published in Ecological Applications, revealed the disappearance of once-thriving kelp forests in these warmer pockets. The research team analyzed historical data on kelp and macroalgae communities in the northern Salish Sea dating back to 1972 through maps, scuba surveys, and aerial photos. In 2023, they conducted a follow-up study to compare the current status with the past findings.
The study uncovered that expansive bull kelp forests once covered over 5.5 million square meters in the northern Salish Sea, particularly around the Comox and Denman Island region. This area had ten times more kelp than the previously estimated baseline set around 2000. Sadly, none of these kelp forests exist today, with satellite imagery indicating a significant loss between 1972 and 1984.
Contrary to popular belief linking recent heatwaves to the disappearance of B.C.’s bull kelp forests, Timmer’s research suggests that the most substantial decline occurred several decades earlier. The study focused on a warm water pocket near Comox and Denman Island in the Strait of Georgia, ranking 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, have risen by 0.25 degrees Celsius per decade, totaling a 1.66-degree Celsius increase. These accelerated warming periods are detrimental to kelp populations, as experts emphasize their vulnerability to such changes.
Kelp plays a crucial role as a foundation species and primary producer in marine ecosystems, supporting diverse marine life with food and habitats. Timmer’s study highlighted a significant decline in sugar kelp and red bladed algae since 1972, attributing it to the warming waters along B.C.’s coast.
William Cheung, a professor at the University of British Columbia, emphasized the importance of establishing accurate baselines to understand historical changes and guide conservation efforts. He noted that revisiting the study in different regions of B.C. would likely reveal more lost kelp habitats.
Timmer collaborates with the Kelp Rescue Initiative and First Nations to restore kelp forests, focusing on protecting suitable areas and replanting kelp species. While the solution is complex, Timmer believes proactive conservation efforts are crucial to safeguarding these vital marine ecosystems.
