Imagine the Grand Canyon, submerged underwater. Now multiply that by 10,000. That’s how many underwater canyons have been identified in the global ocean over the last decade. But while the scientific exploration of canyons advances, so does the human footprint. Increased demand for energy, minerals and fisheries makes it all the more urgent for us to understand and protect these dynamic ecosystems before they are altered or damaged by these human impacts.
This summer, an international community of submarine canyon scientists gathered in Victoria, British Columbia to present state-of-the-art research and discuss new technology, marine policy and conservation. From 25-27 July, Ocean Networks Canada hosted the third INCISE International Submarine Canyon Symposium, the first to be held in North America.
Studying and mapping submarine canyons
Francis Parker Shepard is considered to be the father of marine geology, a gentleman scientist whose love of the sea was inspired through his father’s company, the Shepard Steamship Line in the early 20th century. The opening keynote speech focused on Shepard’s achievements, delivered by his close friend Dr. H. Gary Greene, a distinguished marine geologist who has dedicated his life to studying and mapping submarine canyons.
To date, less than 100 canyons—only 1%—have been studied in any detail. Marine geoscientist Peter Harris has been leading an international program aimed at mapping the oceans geomorphologic features—such as submarine canyons, seamounts, escarpments, ridges, abyssal plains, and trenches. With a goal of marine spatial planning and conservation of marine biodiversity, this project has successfully mapped close to 10,000 submarine canyons worldwide, and fulfills the United Nations Environment Program mandate for ocean stewardship and conservation.
An ocean of biodiversity
Submarine canyons are biodiverse hotspots that provide a unique habitat for a variety of never before seen life forms, such as deep-water corals that rely on hard seafloor surfaces to grow. INCISE co-organizer Veerle Huvenne is a marine geoscientist at the UK’s National Oceanography Centre, where works with post-doctoral fellow and former University of Victoria master’s student Katleen Robert on habitat mapping projects, such as CodeMap. Robert led a presentation on three dimensional habitat mapping methods used to quantify marine animals living on submarine canyons' cliffs and vertical walls. Robert’s and Huvenne’s findings (see figure below) provided insights into the habitat preferences of many invertebrates that live in these steep-walled submarine canyons.
ONC visiting scientist Pere Puig organized a special session on sediment transport through submarine canyons, and a follow-up workshop dedicated to the challenges of monitoring active turbidity currents. Turbidity currents are one of the most important processes for moving sediments from land, across continental margins and into the deep ocean.
Protecting submarine canyons
Derek Fenton, a biologist with Fisheries and Oceans Canada, gave a presentation on the history and challenges of managing marine protected areas. The Gully Canyon, located off Canada’s east coast, is the only protected submarine canyon in Canadian waters and Fenton’s knowledge is helping to build the roadmap for canyon protection on the Pacific coast. Barkley Canyon was identified as a strong candidate to receive special protection against human uses, particularly the destructive bottom trawling fishing methods.
A special session dedicated to Barkley Canyon highlighted research using ONC’s observatory infrastructure. Despite its high biological productivityfrom tiny zooplankton species to large jellyfish and tanner crabssome areas in the canyon contain few species due to low oxygen concentrations. Other studies reveal that Barkley Canyon is the main conduit for the transport of organic materials to the deep sea during winter phytoplankton blooms.
INCISE co-organizer and ONC staff scientist Fabio De Leo delivered a presentation on never-seen observations showing zooplankton layers aggregating deep in the canyon, using ONC’s seafloor cameras. This provided evidence of a higher flux of organic materials channeled through the canyon.
The David Suzuki Foundation recently reached a successful agreement with Canada’s West Coast Fishing Association, resulting in a ban on bottom trawling activities below a depth of 800 m. Jay Ritchlin, Suzuki Foundation Director General, Western Canada, revealed how this will protect a large portion of key habitats, such as glass sponge reefs and deep-sea corals. As part of this unprecedented agreement, fishers now have coral and sponge catch quotas and will be required to report any ‘incidents’ when trawling these and other 'habitat-structuring' species.
Other notable presentations were given by Dr. Susan Allen (University of British Columbia), Dr. Craig R. Smith (University of Hawaii), Dr. Charlie Paull (Monterey Bay Aquarium Research Institute) with support from the following sponsors: National Oceanic and Atmospheric Administration, SubC Imaging, the David Suzuki Foundation and the Deep Sea Biology Society.
“The symposium was a great venue to showcase ONC’s research and infrastructure capabilities to a much larger audience of experts on submarine canyons,” comments ONC staff scientist and INCISE co-organizer Fabio De Leo. "Based on feedback, and on new emerging collaborations, we hope to grow our user community in Barkley Canyon.”
The next INCISE symposium will be held at the Ocean University of China in Qingdao in 2018.