|Bioturbation, geotechnics and microbiology at the sediment-water interface in deep-sea sediments|
Meadows, P.S.; Tait, J. (1985). Bioturbation, geotechnics and microbiology at the sediment-water interface in deep-sea sediments, in: Gibbs, P.E. (Ed.) Proceedings of the 19th European Marine Biology Symposium, Plymouth, Devon, UK, 16-21 September 1984. pp. 191-200
In: Gibbs, P.E. (Ed.) (1985). Proceedings of the 19th European Marine Biology Symposium, Plymouth, Devon, UK, 16-21 September 1984. Cambridge University Press: Cambridge. ISBN 0-521-30294-3. 541 pp., more
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A series of deep-sea sediment samples (water depth 995-2200m, sediment depth 0-0.5m) have been taken in the Rockall Trough area, N.E. Atlantic, using a spade-box corer from which vertical cores were obtained. Microtopographical changes in various biological and geotechnical parameters have been measured. Eb, bacteria, and shear strength have been correlated with depth and with burrow systems. Measurements have shown important small-scale differences within 1 mm to 1 cm at the sea-sediment interface and around burrows. Shear strength increased from ca. 4 9 cm-2 at the sediment surface to 250gcm-2 at 20cm, and Eh decreased from ca. +340mV to ca. +225mV. Heterotrophic bacteria (c.f.u.) fell exponentially from 102-105/g dry weight at the surface to ca. 1/ 9 dry weight at 20 cm. Sediment-surface heterotrophic bacterial numbers and the maximum slopes of the Eb profiles decreased with increasing water depth. Bioturbation was of ten marked (burrow diameter 1 mm to 1 cm) and occurred to a depth of ca. 33 cm. Heterotrophic bacterial numbers in burrow faecal pellets, and burrow Eh and shear strength, were much higher than in surrounding sediment. Bioturbation therefore has dramatic effects on the properties of deep sea sediments.