Submarine canyons as ‘underground rivers’

New Zealand is surrounded by more than 270 deep submarine canyons, which vary in shape and physical characteristics.

The Submarine canyons project uncovered surprising differences in how canyons connect coastal and deep-sea ecosystems (down to 2000 metres depth), using forensic chemistry to track the transport of organic materials derived from watersheds into two contrasting canyons: Kaikoura Canyon, one of the most productive deep-sea habitats in the world, and Hokitika Canyon, which has low productivity.

These results show that our environmental footprint goes (much!) further into the EEZ than previously thought, reaching fragile deep-sea ecosystems which are often assumed to be too remote to be affected by human activities.

Daniel Leduc is a marine biologist at NIWA, and studies the biodiversity and ecology of seabed organisms in deep-sea ecosystems of the New Zealand region.