Fucus serratus is a seaweed of the north Atlantic Ocean, known as toothed wrack, serrated wrack,
Description and reproduction
Fucus serratus is a robust alga, olive-brown in colour and similar to
Fucus vesiculosus and
Fucus spiralis. The species is one of many algae that are multicellular. It grows from a discoid holdfast up to long. The
fronds are flat, about wide, bifurcating, and up to long including a short stipe. It branches irregularly and dichotomously. The flattened blade has a distinct midrib and is readily distinguished from related taxa by the serrated edge of the fronds. It does not have air vesicles, such as are found in
F. vesiculosus, nor is it spirally twisted like
F. spiralis. Male and female receptacles are on different plants.
The lamina shows cryptostomata – small cavities which produce colourless hairs.
The reproductive bodies form in conceptacles sunken in receptacles towards the tips on the branches. In these conceptacles Oogonium and antheridia are produced and after meiosis the oogonia and antheridia are released. Fertilisation follows and the zygote develops, settles and grows directly into the diploid sporophyte plant. The fertilization in the Fucus serratus would be associated with egg activation.
Distribution
Fucus serratus is found along the Atlantic coast of Europe from
Svalbard to
Portugal, in the
Canary Islands.
It was introduced to the shores north-east
Americas over 140 years ago, is presence described first at
Pictou Harbour in the late 1860s by George Upham Hay and Alexander Howard McKay, it's introduction to
Iceland and the
Faroe Islands could date
Viking expansion, within the last 1000 years and was first noted in a phycological survey in 1900.
Ecology
Fucus serratus grows very well on slow draining shores where it may occupy up to a third of the area of the entire seashore.
It often dominates the rocky parts of the lower shore, exposed or immersed in rock pools, on all but the most exposed shores.
"...the
littoral zone is characterised especially by such
Phaeophyta (brown algae) as
Pelvetia,
Ascophyllum,
Egregia,
Fucus and
Laminaria, particularly when the shore is rocky".
It is considered an invasive species in the
The Maritimes, particularly on Prince Edward Island, Nova Scotia and the Northern coastline of New Brunswick. In Northern Europe and Iceland it is known to hybridize with
Fucus distichus.
Uses
Fucus serratus is used in
Ireland and
France for the production of
cosmetics and for
thalassotherapy. In the
Outer Hebrides of
Scotland, it is harvested for use as a liquid fertiliser.
Since the organism contains triacylglycerols and fatty acids.
