The second type are the seaweeds, which are large algae. The largest seaweeds grow low in the intertidalzone and extend out into the subtidal zone. These are the kelps, large brown seaweeds that are glued to the rocks with their holdfast. Their long blades float at or near the surface of the water where they get sunlight to make food, which allows them to grow very fast. Their holdfast glue is very strong, and it can keep the huge kelp in one place even when strong currents and waves occur during storms.