Surfacing on ice of frozen-in marine bottom materials
Journal of the Fisheries Research Board of Canada 31(7): 1195-1200
In late winter and early spring, benthic materials have been observed in patches (maximum size 400 m × 10 m) on the surface of thick fast ice. They parallel the shores of estuaries and are commonest in the southern Gulf of St. Lawrence. Materials in the patches are often in strikingly natural postures and include layers of bottom sediment and plants and animals (eelgrass, shellfish [infauna and epifauna] starfish, flounders, and sticklebacks). Apparently these are frozen to the lower surface of the ice in early winter at low tides, when ice comes in direct contact with them. When the tide rises, the ice floats and raises frozen-on materials with it. Thereafter, the floating ice is thickened by freezing of water to its lower surface, and the bottom materials are thus frozen in between two layers of ice. At the same time the ice above the frozen-in materials is thinned by ablation (sublimation and melting) at its upper surface. Eventually the benthic materials are exposed on the surface ofthe ice. Allied phenomena have been observed in the Bay ofFundy region. Antarctica is the only other place where this has been reported to occur regularly. These phenomena and conditions favoring their occurrence in the two areas are compared.