Sugar wrack

Grows during the winter

The leaf´s growth occurs at the part of the leaf that is attached to the stalk. As new leaf material grows, the older parts are "pushed forward". The stalk and holdfast live for several years. Sugar wrack can be up to 3,5 years old.
Growth of sugar wrack
The sexless variety of sugar wrack is born during the spring and has grown a few centimetres by the summer. During the following year, it grows in length during the winter, in width during the spring and increases in thickness during the summer. It reproduces and creates many sexed plants during the autumn and winter, thereafter the leaf is usually broken apart.

For an alga to grow it needs light to photosynthesise, and nutritive substances. An important nutritive component is nitrogen. Variations in the supply of these substances are great. During the swedish winter months, light is in shortage, but nitrogen is abundant and the opposite situation exists during the summer months. This is a problem for Marine algae, as the ideal situation would be that both components should be abundant at the same time. The next page describes how kelp copes with these variations and how it grows during the winter and summer.
Previous page Page 2 of 9 Next page
Two types
Grows during the winter
Blown asunder
Swaying forests
Animal protection
Three specie of kelp
Lots of kombu
Cures goitre
Used in ice cream

Sugar kelp     More facts     Other names

Home    Contents    Inspiration    Facts    Collaboration   

Aquascope © Aquascope 2000   Tjärnö Marine Biological Laboratory, Strömstad, Sweden
Bo Johannesson | Martin Larsvik | Lars-Ove Loo | Helena Samuelsson