These are the fastest growing and largest algae, growing up to 13mm in one day. The enormous sporophyte plants have a long life span and form commodious underwater forests. They possess root-like anchorings with long stripes or stalks which act as support to the blades. The tissues of the kelps are specialized for photosynthesis, reproduction, support and for the transport of nutrients. Numerous minute spores are released from the blades and form small gametophyte plants (male & female). Kelps are harvested for the extraction of algenic acid which is used as a gel in food products, paint, ink and toothpaste. It is also used to waterproof cement and to stabilize earth embankments. It has great importance as a fertiliser with good water-holding capabilities, a natural fungicidal action and it is rich in certain mineral salts. Fresh kelp contains growth hormones that increase the produceof crops such as wheat. A unique ecosystem is created within the kelp forests in that they break the force of waves and form a sheltered habitat. Many animals also rely on the kelps as a source of food (they either consume the soup of fine particles that frequently erode from the tips of the fonds or they graze the plants).