‘Beware of the Sea! If thou hearest the cry of the gull on the shore, Thy heart shall then rest in the forest no more.’J.R.R. Tolkien: The Lord of the Rings (Galadriel to Legolas). 1954
Have you ever snorkelled in a forest? That sentence may look oxymoronic (at the very least), but it is in fact a perfectly valid question, as any local diver will confirm. Our shoreline waters in the Peninsula are lined with forests, and these dense offshore patches of green are both beautiful to observe and fascinating to investigate.
We are referring, of course, to ‘kelp’ forests, and these incredible stretches of underwater vegetation are found all around the world in temperate waters and polar coastal regions. You don’t have to own a mask and snorkel (or scuba gear) to be enthralled, either: our own Two Oceans Aquarium has an incredible 800 000 litre tank Kelp Forest that mimics the ocean perfectly, and through its (thick) glass front guests can watch the kelp ‘enchanted forest’ with its equally enchanting inhabitants sway back and forth, pushed by plunger that creates a surge and by pumping 70 000 litres of water per hour around the tank; also supplemented by ‘dump boxes’ that tip large volumes of water in at random intervals to stir up the nutrients. Open to the sky above to allow the natural sunlight to photosynthesize, the challenge is to keep the water to a steady 12 to 15 degree Celsius range; ideal for the kelp to thrive. This is achieved through chillers that combat the summer sun that tourists love so much.
What – apart from the beauty of the forests which are hidden from beach-bound humans – makes kelp special? Just to begin with, the Two Oceans Aquarium use the kelp tank as a natural water filter. Kelp thrive on the waste products produced by fish – mainly ammonia – as well as potentially harmful dead algae blooms, so the kelp tank actually has the best quality water in the aquarium. The forests also support many species of fish and other marine wildlife (more on this later): according to the Two Oceans website: ‘species such as southern mullet, strepies and hottentots, live permanently in kelp forests where they find food and shelter, while others, such as Cape salmon, giant kob and even yellowtail, move in and out of kelp forests in search of food.’ As far as the smaller organisms are concerned, more than 100,000 mobile invertebrates per square meter are found on kelp stipes in well-developed kelp forests. These in turn feed a wealth of other creatures, creating a living vibrant food chain that then assists in keeping our oceans healthy. Kelp munch enormous amounts of carbon too; yet another link in the chain that combats climate change.
Kelp is not a tree; in fact its not even a plant, fungus or animal – it’s a algae of the stramenopile order, and we are not going to even attempt to go down that road of eucaryote discovery; simply put it has been around since Miocene times, is related to diatoms (which are tiny) and has ‘blades’ that can grow up to half a metre a day up to 80 metres is length (which is very big). The name’ kelp’ is obscure; the best we can come up with is that it is based on the Middle English word for seaweed ‘culpe’, the origins of which nobody can trace any further. A kelp strand is divided into three distinct areas: the blade or stem, referred to above, which grows from a ‘stipe’, and the ‘holdfast’ that anchors it to the seabed or rock. Capetonians will be aware of the piles of kelp that wash up on beaches after storms have created surges that break the holdfasts from their positions. (Dried out, these holdfasts, with a little careful adaptation, can make amazing horns for those capable of blowing bugles or the benighted vuvuzelas.)
Kelp has been utilised by humans since we first started trundling along shorelines; the South African Strandlopers would settle around kelp areas, and middens excavated by researchers along the Cape coastline have shown that the bulk of their food was spawned in the kelp – abalone, limpets, and mussels. This is reflected on a worldwide scale: kelp forests around the Pacific Rim may have facilitated the dispersal of anatomically modern humans following a coastal route from Northeast Asia to the Americas – the Kelp Highway Hypothesis, for budding anthropologists to research. Rich in iodine and alkali, as a product, kelp has been used as a food, and in ash form in glass and soap production. You’ll find it in products such as ice cream, jelly, salad dressing, and toothpaste, as well as an ingredient in dog food and in manufactured goods, and it is also frequently used in general dentistry and orthodontic applications. Sadly, it also contributed to a considerable number of deaths during the wars that ravaged the world in the era of gunpowder: kelp was harvested extensively as a source of potash.
We haven’t even scratched the surface of this ocean wonder: we highly recommend a trip to the Two Oceans Aquarium on your way to a Waterfront Charters cruise; it’ll show you the stunning beauty of the underwater kingdom, forests and all before we show you the wonders of the Atlantic surface and the Cape mountains and scenery. With World Ocean Day coming up in April it’s also frightening to note that kelp forests that have remained unchanged for millennia are now being affected by overfishing, pollution and loss of habitat. It’s yet another aspect of marine conservation that will affect us here in the beautiful Cape, and we urge everyone to make themselves aware of the necessity of conservation. It’s time to turn the tables on destructive habits and ensure that our planet keeps its natural resources. We owe it to the future generations.