. Elements of ecology. Ecology. 68 The Substratum examples of the control of bottom fauna and flora by the substratum in coastal water are given by Yonge (1949) and by Pratt (1953), and in fresh water by Krecker and Lancaster (1933) and by Wilson (1939). Farther offshore conditions cannot be so easily observed, but the modern quantitative dredge and the underwater camera have shown that the same selective action is being exerted by the nature of the bottom material. Samples dredged from mud and from coarse shell- gravel at locations only a few miles apart in the English Channel were shown by W
. Elements of ecology. Ecology. 68 The Substratum examples of the control of bottom fauna and flora by the substratum in coastal water are given by Yonge (1949) and by Pratt (1953), and in fresh water by Krecker and Lancaster (1933) and by Wilson (1939). Farther offshore conditions cannot be so easily observed, but the modern quantitative dredge and the underwater camera have shown that the same selective action is being exerted by the nature of the bottom material. Samples dredged from mud and from coarse shell- gravel at locations only a few miles apart in the English Channel were shown by Wilson (1951) to contain strikingly different animal types. Such differences influence fish populations feeding upon these ben- thonic species. Studies made with the underwater camera have the advantage that they reveal the nature of the bottom material and the organisms living on it in their undisturbed condition. The dimen- sions of bottom features such as ripples, and the spatial distribution of the inhabitants may then be examined quantitatively (Fig. ). In the abyssobenthic zone of the ocean the bottom material usually con- sists of a soft mud, and here only those animals with long legs, broad bases, or other special adaptation can move about without being smothered. At a depth of 1% miles the candid underwater camera caught a 60-cm "sea cucumber" as it cruised across the muddy bottom. Photo made with Eicing undersea camera by J. ;, H'uads Hole Oceanographic Institution Fig. A holothurian ("sea ciK;umber") moving over the mud at a depth of 2600 m {\Yj, miles) on the floor of the open oeean ofl:' the coast of New York. Note the imprint of the double row of tube Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Clarke, George L. (George Leonard), 1905-. New York, Wile
Size: 1709px × 1463px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookpublishernewyorkwiley, booksubjectecology
