. The Earth beneath the sea : History . « •"<• Fig. 33. 41° 18']Sr, 14° 'W. Depth 5341 m. Iberia abyssal plain. Area of picture 1 by 1 m. (Photo by ) Broad tracks (15 cm wide) in Globigerina ooze made by a mud-feeding animal on the surface. Note the regular indentations (5 cm apart) either side of the tracks and the transverse markings (top left) suggesting a mud-scooping action resulting in a central ridge. Smaller but more numerous tracks have been identified as having been made by smaller holothurians and sea-urchins (Fig. 34). Unidentified animals with long thin conical
. The Earth beneath the sea : History . « •"<• Fig. 33. 41° 18']Sr, 14° 'W. Depth 5341 m. Iberia abyssal plain. Area of picture 1 by 1 m. (Photo by ) Broad tracks (15 cm wide) in Globigerina ooze made by a mud-feeding animal on the surface. Note the regular indentations (5 cm apart) either side of the tracks and the transverse markings (top left) suggesting a mud-scooping action resulting in a central ridge. Smaller but more numerous tracks have been identified as having been made by smaller holothurians and sea-urchins (Fig. 34). Unidentified animals with long thin conical shells (resembling scaphopods), with two extended arms, have often been photographed at the end of thin and rather angular tracks (Fig. 35). Occasionally fish feeding near the bottom leave marks where the lower tip of the tail touches the sediment surface. The greatest contribution to the disturbance of the sediments is due, how- ever, to the galleries and dwelling holes of burrowing worms and other infauna which are visible to the camera only where they come to the surface. However, they are shown up well in cross-sections of cores in the region where the sedi- ment colour changes. Galleries bored in the lower material become filled subsequently with the upper material and this constitutes a mixing process. The only evidence of these galleries in underwater photographs is the sudden
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Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
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Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectoceanbottom
