Section 44. Bottom Ice 



Bottom ice is a variation of deep ice, formed in shallows, and in certain cases is more sig- 

 nificant than deep ice. 



Bottom ice in the sea is an extremely widespread phenomenon not only in northern but also in 

 southern seas . * 



Similar cases were also known in the Baltic Sea. Thus, in some years at the beginning of 

 winter, ships found themselves surrounded by ice which had suddenly risen from the bottom of the 

 sea, this was proved by sand and bottom objects that had floated up along with the ice. 



It is known, for example, that bottom ice along the rocky shores of Greenland, Labrador, and 

 Spitzbergen often raise chunks of rocks and bottom with themselves to the surface of the sea. Along 

 the shores of Newfoundland, bottom ice has been encountered at depths of 20 to 30 meters. 



Rodman notes a case when a box of instruments was carried to the surface of the sea by bot- 

 tom ice. It happened that this box had belonged to a ship that had gone down many years ago in 

 Hudson Strait, several hundred miles north of where it was found. 



In separate regions along shallow shores, the sea freezes to the bottom and the ice fuses 

 solidly with the bottom. When melting begins, the upper layers of this ice are covered with water, 

 which preserves the ice from the direct action of solar radiation and heat exchange with the air. 

 Aside from this, fragmented shore material is gradually deposited on the ice, which protects the 

 remnants of the ice not only from the heat but also from the erosive action of water. 



It is clear that under such conditions the ice frozen to the bottom is preserved for a very long 

 time. Thus, Samoilov notes that in Khatangskii Gulf ice islets frozen to the ground were disclosed 

 during the low tide on 27 July, 1937, 1.5 km from the shore. 



In Biruli's opinion, who had observed the same phenomenon on the southern shore of the 

 Taimyr Strait, spring bottom ice can remain for many years if the winters are especially harsh and 

 if the sea is at a low level. 



As spring bottom ice melts, parts of it break loose and float up to the surface of the sea, 

 along with particles of the bottom and underwater stones which have frozen to it, and with products 

 of spring-shore run-off which have been deposited on its upper surface. 



During exceptionally warm years, chunks of old bottom ice, whose upper surface has not only 

 bottom deposits but also marine organisms which have developed on it during the time it was under 

 water, can float up to the surface in the same manner. 



*Thus, according to announcement by Snezhinskii, the fishermen of the Dilzhanskii station on 

 the Azov Sea indicate bottom ice forms annually along the western side of the Dolgaia sand pit. 

 They assert that if a 40-centimeter rod is driven into the bottom, leaving one-tenth of the rod 

 above the surface of the bottom, coarse bottom ice will begin to form on the rod in such dimensions 

 that finally the rod will pull out of the bottom and along with the ice will rise to the surface of the 

 sea. It is characteristic that on the eastern side of the sand-spit bottom ice does not form. The 

 formation of bottom ice was also observed during certain years on the western side of the 

 Berdianskiya sand-spit; this happened only when the sea was open. 



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