No, they are frozen to continental ice sheets.
Sea ice contains frozen minerals, such as salt, that is not frozen into freshwater ice.
If the ice shelves are on land, then, yes, when they melt, sea levels will rise. If they are floating, then sae levels will not rise.
Floating ice can be found in polar regions such as the Arctic and Antarctic oceans, where sea ice forms from frozen seawater. This ice can form large ice shelves, icebergs, and sea ice cover, depending on the region and conditions.
The centre of Antarctica has had snow falling on it for about 100,000 years. This snow doesn't melt but becomes ice with the weight of more snow on top. This is 7 million cubic miles (30 million cubic km) of ice.This huge weight of ice forces the ice outwards radially all round the coast in the form of ice shelves that float out on the surface of the ocean. Some of these shelves rest on the sea bed. The ocean is warming and the warmer water melts the ice underneath the shelves, so the shelves become thinner and break off to form icebergs.
Ice shelves in Antarctica are melting at an accelerating rate due to warming ocean temperatures and increased melting from the bottom. This can lead to the destabilization of the ice shelves and contribute to rising sea levels as more ice flows into the ocean. Scientists are closely monitoring these changes to understand their impact on the stability of the Antarctic ice sheet.
The frozen sea is a sea that has become so cooled as to allow ice to form on the surface.
Ice glaciers contribute to sea level rise because they are land-based ice that, when melted, adds water to the ocean. In contrast, melting ice shelves, which float on the ocean, do not directly raise sea levels since they are already displacing water. The melting of ice shelves can indirectly influence sea level rise by allowing glaciers to flow more rapidly into the ocean, but their direct contribution to sea level change is negligible compared to that of land glaciers.
The frozen sea is a sea that has become so cooled as to allow ice to form on the surface.
You may be thinking of ice shelves, one of which, the Ross Ice Shelf, is about the size of France. Ice shelves are attached to the Antarctic continent, but float in the sea and do not count in the total square kilometer measurements of it.
Antarctica's ice sheet rests on 98% of the continent. It has been said that the ice is so heavy, ". . . In East Antarctica, the ice sheet rests on a major land mass, but in West Antarctica the bed can extend to more than 2,500 m below sea level." Quoted from the Antarctic Ice Sheet entry in Wikipedia. This is some, not most of the ice sheet. Ice shelves exist mostly below sea level.
Icebergs (drifting ice) in Antarctica have broken off from the glaciers and ice shelves that stretch out over the sea at the continent's coastline.
extremely low tempuratures.