Kelp Forest

Scotlands Living Landscapes

• Foreword
• Introduction
• What is kelp and where is it found?
• Why kelp forests are important in Scottish coastal waters
• Scottish kelp plants
• Light – the critical factor
• Oarweed forests
• Cuvie forests
• Kelp parks
• Beyond the kelp zone
• Kelp productivity
• Uses of Kelp
• Kelp harvesting
• Afterword

Why kelp forests are important in Scottish coastal waters

In many ways, kelp forests are the Scottish equivalent of tropical coral reefs; both are found in shallow coastal waters, and both perform similar functions in the marine environment.

Kelp forests and coral reefs provide three-dimensional ‘living space’ for animals and plants. Small animals such as worms and crustaceans live in gaps in the branching kelp holdfasts, while the plant surfaces support a diverse range of colonial animals (such as sea mats and sponges) and red seaweeds. Animals and plants also live on the rock surface between kelp plants, and small fish shelter from predators in the shade of the blades.

A column of water in which a giant kelp plant grows can support several thousand times as many animals as a column of water stretching above a barren ocean floor. Although an equivalent figure cannot be given for Scottish kelp plants, it is known that large numbers of animals live in the forests in comparison to areas devoid of kelp.

A second important function of both kelp forests and coral reefs is the production of organic material. In a similar way to land plants, kelps and the other seaweeds found in kelp forests grow by fixing carbon dioxide through the process of photosynthesis. The resulting vegetation eventually dies, producing flakes of rotting plant material and dissolved chemicals derived from plant material, both of which act as food sources for bacteria and single-celled animals. These, in turn, provide food for larger animals such as fish and lobsters. This is similar to a forest on land, where rotting leaf-litter enriches the soil and encourages the growth of mites and insects which are eaten by birds, hedgehogs and badgers.

In a coral reef, the organic material is produced by millions of tiny one-celled plants which live in association with the coral, and by a range of other seaweeds living on the reef.

Fringing reefs around coral islands protect the islands from oceanic storms, and prevent these vulnerable, low-lying outcrops of coral sand from being washed away by the waves. In a similar way, it is believed that kelp forests reduce the erosive impact of Atlantic waves on some Scottish shores, in particular those of the Outer Hebrides and Northern Isles.