Kelp beds are the equivalent of underwater forests. Kelp can be useful in many ways to the diver. It allows a good estimate of clarity of the water by assessing the length of plant seen from the surface. The kelp blades indicate the direction of the prevailing current. In kelp beds there is usually an abundance of marine life, and the kelp offers other benefits such as dampening wave action both in the area and the adjacent beach. Kelp can be used as an anchor chain for people to use when they are equalizing their ears, as well as to attach other objects such as floats, diver’s flags, surf mats, specimen bags and so forth.
Giant members of this large brown algae or seaweed may grow in clear water to depths of 30 metres. The growth is less in turbid or unclear water. Kelp usually grows on hard surfaces, e.g. a rocky bottom, a reef or, for more romantic divers, a Spanish galleon. It is of interest commercially because it is harvested to produce alginates, which are useful as thickening, suspending and emulsifying agents, as well as in stabilizing the froth on the diver’s glass of beer (après dive, of course).
Kelp has caused many diving accidents, often with the diver totally bound up into a ‘kelp ball’ that becomes a coffin. The danger of entanglement is related to panic actions and/or increased speed and activity of the diver while in the kelp bed. Twisting and turning produce entanglement.
Divers who are accustomed to kelp diving usually take precautions to ensure that there is no equipment that can snag the strands of kelp; i.e. they tend to wear knives on the inside of the leg, tape the buckles on the fin straps, have snug quick-release buckles and not use lines. Divers descend vertically feet first to where the stems are thicker and there is less foliage to cause entanglement. The epitome of bad practice in kelp diving is to perform a head first roll or back roll because it tends to result in a ‘kelp sandwich with a diver filling’.
The kelp is pushed away by divers as they slowly descend and ascend; i.e. they produce a clear area within the kelp, into which they then move. They ensure that they do not run out of air because this situation will produce more rapid activity. If they do become snagged, divers should avoid unnecessary hand and fin movements. Kelp can be separated either by the use of a knife or by bending it to 180 degrees, when it will often snap (this is more difficult to achieve while wearing gloves). It is unwise to cut kelp from the regulator with a knife without first clearly differentiating it from the regulator hose. Some divers have suggested biting the strands with one’s teeth. This may be excellent as regards dietary supplementation, kelp being high in both B vitamins and iodine, but it does seem overly dramatic.
Kelp does float, and it can often be traversed on the surface by a very slow form of dog paddling or ‘kelp crawl’, in which one actually crawls along the surface of the water, over the kelp. This can be done only if the body and legs are kept flat on the surface, thus using the buoyancy of both the body and the kelp, and by using the palms of the hands to push the kelp below and behind as one proceeds forward. Any kicking that is performed must be very shallow and slow.