Along the Dallas Road breakwater in Victoria, kelp forests thrive beneath the cold waters, as explained by Brian Timmer, a PhD student at the University of Victoria (UVic). While these areas are flourishing due to the cool environment, other regions in British Columbia are experiencing warming microclimates where kelp forests have vanished.
A recent study led by Timmer from UVic and published in Ecological Applications examined historical data on kelp and macroalgae communities in the northern Salish Sea. By analyzing maps, scuba surveys, and aerial photos dating back to 1972, the research team compared the past kelp coverage with present conditions.
The study revealed that the expansive bull kelp forests that once spanned over 5.5 million square meters in the northern Salish Sea, particularly around the Comox and Denman Island area, have drastically declined. This loss is ten times greater than the previously established baseline around 2000.
Satellite imagery confirms that the majority of bull kelp disappearance occurred between 1972 and 1984. Despite the common belief that recent heatwaves were causing the decline, Timmer’s research suggests that the most significant loss occurred decades ago.
Timmer’s study focused on a warming pocket of water near Comox and Denman Island, which is among the top 10% globally in terms of ocean warming temperatures. Over the past 50 years, sea surface temperatures at the Chrome Island lighthouse have risen by 0.25°C per decade, totaling a 1.66°C increase.
Kelp, considered a foundation species and primary producer, plays a crucial role in marine ecosystems by providing food and habitat for various sea creatures. The decline in kelp populations, especially accelerated by warming waters, poses a threat to marine biodiversity.
Experts emphasize the importance of establishing accurate baselines to understand ecological trends and inform conservation efforts. Timmer’s research highlights the urgent need to protect and restore kelp forests in British Columbia by identifying suitable habitats and reintroducing kelp species through initiatives like the Kelp Rescue Initiative.
In collaboration with First Nations, Timmer aims to address the decline in kelp populations and mitigate the impacts of warming waters on marine ecosystems.