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The Nazare Canyon:
A virtual tour
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The Nazare Canyon lies between 39° and 40° N and is a relatively simple canyon system that extends from the coast of Portugal to the Iberian Abyssal Plain at more than 5000 m water depth. Although the canyon head is almost in contact with the beach, It does not connect with a river, but still acts as a major conduit of sediment because it intersects the continental shelf almost completely and therefore captures all along-slope sediment transport.
The Nazare Canyon is one of a series of canyons along the Portuguese margin, including the Setubal Canyon.
Right: 3D map of the Portuguese canyons.
Click on image to enlarge.
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Mapping of the canyon has revealed highly variable topography. The upper slope, for instance, between 700 and 1400m, is characterised by steep slopes, gullies, terrace-like features and a V-shaped canyon floor profile. Deeper, the canyon floor broadens out to about 100 to 200m. Below about 4000m the canyon is about 5 to 6 km wide with a central channel evident about 100 to 200m across, resembling in many ways a river valley.
Above: Bathymetric image of the Nazare Canyon. The colours indicate water depth - green is shallow (coastal); dark blue-purple is deep sea.
Land is coloured yellow and orange. Image courtesy NOCS.
The images presented below were taken using a digital camera mounted on the ROV Isis during research cruise JC10 aboard RRS James Cook in June-July 2007. All images are copyright NOCS. Click on the images to view a larger version.
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Nazare Canyon, 800m water depth
Dumbo Octopus resting on sediment with small rock outcrops nearby
Image: ROV Isis (NOCS JC10 cruise, summer 2007)
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Nazare Canyon, 1130m water depth
Gorgonian corals extending out from a solid, vertical rock face
Image: ROV Isis (NOCS JC10 cruise, summer 2007) |
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Nazare Canyon, 1180m water depth
Brisingella resting on sediment that also shows evidence (in the form of holes) of bioturbation by animals living in the sediment.
Image: ROV Isis (NOCS JC10 cruise, summer 2007)
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Nazare Canyon, 1220m water depth
Soft corals extending out from a vertical rock face to capture particles in the water column. The steepness of the rock face can be clearly seen.
Image: ROV Isis (NOCS JC10 cruise, summer 2007) |
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Nazare Canyon, 1300m water depth
Bright red anemone attached to rock
Image: ROV Isis (NOCS JC10 cruise, summer 2007)
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Nazare Canyon, 1300m water depth
Coral and seastars on rocky outcrop, demonstrating a typical filter-feeding community.
Image: ROV Isis (NOCS JC10 cruise, summer 2007)
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Nazare Canyon, 1300m water depth
Echinothurid (sea urchin) on rocky outcrop. These types of sea urchin have a shell that is flexible whereas in most sea urchins the shell is rigid.
Image: ROV Isis (NOCS JC10 cruise, summer 2007)
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Nazare Canyon, 1440m water depth
Anemone on rocky outcrop. This anemone is hanging down from a small overhang in the rock face.
Image: ROV Isis (NOCS JC10 cruise, summer 2007) |
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