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Submarine canyons harbour rich biodiversity owing to their complex geomorphology and hydrological regimes. They also exhibit large bathymetric gradients in temperature, oxygen, food supply, and sedimentation rates, making submarine canyons excellent case studies for adaptation and tolerance of marine organisms to ocean change. Barkley Canyon is a submarine canyon located off the west coast of Vancouver Island, British Columbia, ranging from 200m where the apex meets the upper slope, down to 2200m on the continental rise. Much of the canyon sits in the core of the Northeast Pacific (NEP) Oxygen Minimum Zone (OMZ), where oxygen concentrations are as low as 0.2 mL/L. Recent research has demonstrated a startling 15% overall decline in dissolved oxygen in the upper 3000m of the NEP over the past 60 years, faster than the global average, with concurrent deepening and shoaling of the OMZ’s hypoxic boundary. Furthermore, a recent marine heatwave in 2013-2015 (“The Blob”) wreaked havoc on the NEP, leading to mass die-offs of seabirds, range shifts and topicalization of zooplankton, fisheries closures, and an unprecedented harmful algal bloom. However, the effects of the warm blob on the benthic megafauna in the NEP is largely unknown.

Ocean Networks Canada’s NEPTUNE cabled observatory node at Barkley Canyon collects continuous, high-resolution environmental data and high-definition video at the seafloor from the upper slope (400m) to the Cascadia basin (2200m). We are utilizing instruments at the Upper Slope and in the Axis (1000m) of the canyon to study the effects of ocean change over time on benthic megafauna in and around Barkley Canyon. This work will provide insight into how regular environmental variation influence benthic megafauna over time, and the role of extreme climate events in structuring seafloor communities.