Graveyard Seamounts

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Graveyard Seamounts
Summit depth 750 to 1,000 m (2,461 to 3,281 ft)[1]
Height 100 to 400 m (328 to 1,312 ft)[1]
Summit area 140 km2 (54 sq mi)[1]
Location
Location Chatham Rise, east of New Zealand[1]
Coordinates 42°45′S 180°0′W / 42.750°S 180.000°W / -42.750; -180.000Coordinates: 42°45′S 180°0′W / 42.750°S 180.000°W / -42.750; -180.000
Country New Zealand
Geology
Age of rock Late Cenozoic

The Graveyard Seamounts are a series of 28 small seamounts (underwater volcanoes) and ediffices located on the Chatham Rise, east of New Zealand. They cover about 140 km2 (54 sq mi), and stand out from the surrounding oceanic plateau that measures several hundred kilometers. They are named after various morose figures, and the most prominent among the group are Ghoul Seamount, Diabolical Seamount, Voodoo Seamount, Scroll Seamount, Hartless Seamount, Pyre Seamount, Gothic Seamount, Zombie Seamount, Mummy Seamount, Headstone Seamount, Morgue Seamount and Graveyard Seamount (ordered roughly by size).[1]

Geography and geology[edit]

The seamounts are the site of volcanism from the late Cenozoic era. The seamounts are 100 to 400 m (328 to 1,312 ft) high, stand 1,050 to 1,200 m (3,445 to 3,937 ft) deep at their base and 750 to 1,000 m (2,461 to 3,281 ft) at their summit. Many of the seamounts bears marks of tidal scour from water erosion, the result of millions of years of wear by a current moving at 1 to 2 cm (0.4 to 0.8 in) per second.[1]

Ecology[edit]

The Graveyard Seamounts are a home to over 50 species of fish, dominated by the orange roughy (Hoplostethus atlanticus), black oreo (Allocyttus niger), and cardinalfish (Apogonidae). Orange roughy in particular aggregate on the Graveyard seamounts for spawning, and their visits here have supported a commercial fishery since the mid-1990s. A number of the seamounts are also home to extensive deep water coral forests, made up of Solenosmilia variabilis and Madrepora oculata, both species not known to be of wide extent near New Zealand until camera surveys of Graveyard Seamounts in 2001 revealed their and extent. These forests offer a home to a diverse invertebrate community that includes squat lobsters, seastars, brittlestars, polychaete worms, and crabs. In contrast, the seamounts in the group that are affected by bottom trawling are mostly barren, with few coral and a completely different ecosystem.[1]

In 2001, witnessing the damage of bottom trawling to seamount communities, 19 seamounts off the coast of New Zealand were closed off to bottom trawling, three of them from the Graveyard group. Timed surveys of the seamounts over the years are being used to examine how well a seamount coral community recovers from the effects of dredging over time.[1]

See also[edit]

References[edit]

  1. ^ a b c d e f g h Malcolm R. Clark, Ashley A. Rowden, Ian Wright, Mirelle Consalvey. "Spotlight 7: Graveyards Seamounts" (PDF). Oceanography (Oceanography Society). Retrieved 26 July 2010.