Ice scour is a geological term for long, narrow ditches in a seabed

Seabed

The seabed is the bottom of the ocean.- Ocean structure :Most of the oceans have a common structure, created by common physical phenomena, mainly from tectonic movement, and sediment from various sources...

, created by the collision of fast ice

Fast ice

Fast ice is sea ice that has frozen along coasts along the shoals, or to the sea floor over shallow parts of the continental shelf, and extends out from land into sea. In Antarctica, fast ice may also extend between grounded icebergs...

 and pack ice and the grounding of iceberg

Iceberg

An iceberg is a large piece of ice from freshwater that has broken off from a snow-formed glacier or ice shelf and is floating in open water. It may subsequently become frozen into pack ice...

s. Synonyms include ice gouging, ice ploughing, ice score and keel scour. This phenomenon is common along the northern coast of Alaska and in the Bering Sea along its costal waters.

It may also refer to ice sheet

Ice sheet

An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² , thus also known as continental glacier...

s in the intertidal, which upon movement of the ice, creates physical abrasion and possible dislodgment of marine organisms.

Regions of the seabed reshaped by ice scour have been linked to the formation of black pools, seabed depressions filled with anoxic

Hypoxia (environmental)

Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...

high-salinity water which are death traps for small marine organisms.