Browsing by Author "Frans, Rene"

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    Of dead man's fingers, cord weed and hanging wrack: common brown seaweeds of the Cape Peninsula
    (Botanical Society of South Africa, 2000) Maneveldt, Gavin; Frans, Rene
    In this, the second in the series on common intertidal seaweeds of the Cape Peninsula, we look at the brown seaweeds common to our rocky shores, with the exception of kelp, which will be covered in the next issue of Veld & Flora. Unlike the green seaweeds mentioned in the previous issue, these brown seaweeds are generally slower growing and are less tolerant of salinity and temperature extremes and thus more prone to desiccation stress. They therefore tend to occur lower down on the shore than the green seaweeds.
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    Of dinner plate, cochlear and pacman corallines: seven common intertidal encrusting red seaweeds of the Cape Peninsula
    (Botanical Society of South Africa, 2001) Maneveldt, Gavin; Frans, Rene
    In the fifth and final part of this series of articles on common intertidal seaweeds of the Cape Peninsula, we look at encrusting coralline algae. These encrusting coralline and red seaweeds are widespread in shallow waters in all the world’s oceans, where they often cover close to 100% of rocky substrates. Nowhere are they more important than in the ecology of coral reefs. Not only do encrusting coralline algae help cement the reef together, but they make up a considerable portion of the mass of the reef itself and are important primary products and food for certain herbivores.
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    Of purple laver, tongue weed and hedgehog seaweed: common red seaweeds of the Cape Peninsula
    (Botanical Society of South Africa, 2001) Maneveldt, Gavin; Frans, Rene
    The fourth part of our series on the common intertidal seaweeds of the Cape Peninsula looks at the red seaweeds, which form by far the largest group of seaweeds on the Peninsula and dominate the mid to lower intertidal area to a large extent. Like the brown seaweeds many of the reds are fleshy and bulky and generally occur lower down the shore because they are less tolerant of salinity and temperature extremes than some of the common green seaweeds.
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    Of sea bamboo, split fan kelp and bladder kelp: three common kelp species of the Cape Peninsula and West Coast
    (Botanical Society of South Africa, 2001) Maneveldt, Gavin; Frans, Rene
    The third part in our series on the common intertidal seaweeds of the Cape Peninsula looks at the kelps, the giant brown seaweeds that occur in the subtidal and intertidal gullies of the Cape Peninsula and the west coast. Like trees an ancient forest, kelp dominate the canopy of the subtidal zone in the cool, nutrient-rich waters of the South African west coast. Kelp is the largest and fastest growing of the seaweeds, growing as much as 13 mm in a day. Some of these seaweeds as the giant kelp (Macrocystis pyrifera) of central and southern California are known to grow to over 30 m in length.
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    Of sea lettuces and green sea intestines: common intertidal green seaweeds of the Cape Peninsula
    (Botanical Society of South Africa, 2000) Maneveldt, Gavin; Frans, Rene
    Most of us know seaweed as that slippery stuff growing on the rocks or lying strewn along the beach at low tide making the beach smell. But do we really know much about them? Although not entirely true, seaweeds (or marine algae) are generally considered to be plants because they use solar energy to produce carbohydrate food from carbon dioxide and water (photosynthesis). They are simpler than land plants as they have no roots or shoots. Seaweeds absorb nutrients directly from the seawater; and therefore have no need for roots or complex conductive tissue. Some large seaweeds do however have root-like structures called holdfasts and leaf-like fronds that act like shoots. The photosynthetic pigments they possess reflect certain colours of light, producing what appear to be green, brown and red seaweeds, and thus they are divided into three main groups: green brown and red. In this article we examine some of the green seaweeds that occur in the Cape Peninsula.