Hypnea spicifera, commonly called
green tips, occurs as dense green and
purple clumps on the lowest parts of
the shore and is often only visible during low water of spring tides. The
upper parts of the clumps are covered
with numerous short green fleshy
spines. The colour in this species is
characteristically purple-brown at the
base and a luscious translucent green
at the tips. The chlorophyll completely masks the red pigment near the
upper surface of the seaweed. This
seaweed is able to form extensive
mats on the lowest reaches of the
shore because of its rhizomatously
spreading holdfast.
Green tips, Hypnea spicifera, is a common seaweed of the low
shore.
Economic value and use
Of all the seaweeds, the reds are
probably the most economically
valuable. The genus Porphyra in
particular makes at least 80 % of all
seaweed harvested all over the
world. In Asia, it is known as nori
and is eaten as a whole seaweed
either dried or in soups, or as tasty
wrappings for sushi and rice. The
iodine, and high vitamin and protein content of nori makes it popular, as does the relative simplicity of
its mariculture (sea farming), which
began more than 300 years ago in
Japan.
fore excellent as stabilizing and gelling agents. The main phycocolloids derived from red seaweeds are
carrageenan and agar. Carrageenan is important in the dairy industry – milkshakes, cheese, joghurts
and powdered milk (including baby
formula) all possess red seaweed
extracts. Carrageenan is even used
in pet food, cosmetics, shampoos,
paints and toothpaste. A number
of carrageenophyte seaweeds are
being investigated in South Africa,
including H. spicifera and various
species of Gigartina, Sarcothalia
and Aeodes.
Red seaweeds are also important
for their phycocolloid extracts,
which cause particles to remain suspended in solution and are there-
Agar on the other hand, has its
most important use as a medium
on which to culture fungi and bacteria in microbial and medical
pathological research. In food for
human consumption agar can be
found in baking and confectionary
products and is also widely used to
clarify wine, juice and vinegars because of its excellent protein binding properties. In larger industries
agar is used to make adhesives and
capsules for tablets. South African
agarophytes include the seaweed
genera Gracilaria (which was harvested extensively in Saldanha Bay)
and Gelidium.
What does that mean?
Stoloniferous: After stolon (often
called runners), a horizontal
branch from the base of a plant
that produces new plants from
buds at its tips.
Further Reading
Maneveldt G.W. 2014. You use seaweeds for that? Agri-Kultuur/Culture 17(Aug): 34-37. http://www.joomag.com/
magazine/agri-kultuur-augustus-august-2014/0879370001407230054.
Maneveldt G.W. 2015. Between the tides and a hard place. Agri-Kultuur/Culture 25(May): 76-78.
http://www.joomag.com/magazine/agri-kultuur-may-mei-2015/0281153001432115597?short.
Maneveldt G.W. 2015. Common green seaweeds of the Cape Peninsula. Agri-Kultuur/Culture 27(July): 48-49.
http://www.joomag.com/magazine/agri-kultuur-july-julie-2015/0965897001437655565.
Maneveldt G.W. 2015. Common brown seaweeds of the Cape Peninsula. Agri-Kultuur/Culture 30(October): 60-63.
http://www.joomag.com/magazine/agri-kultuur-october-oktober-2015/0680220001445836697?short
Maneveldt G.W. 2015. Common kelps of the Cape Peninsula. Agri-Kultuur/Culture 31(November):
https://www.joomag.com/magazine/agri-kultuur-november-november-2015/0090737001448432884