Seafloor communities in general depend on food supplied from the water column above. It is the food supply and not the cold water temperatures per se that appear to restrain growth and survival of the seafloor animals in the Arctic. Specific habitats can be formed by the mineral of substrates as well as free-living (not attached to the substrate) organisms such as coralline algae in the Order Corallinales, which can form Rhodolith reefs. Such reefs are e.g. found in the Kongsfjord in Northern Norway.