2005 - Whitby Naturalists

magically calmed the weather and the waves-hence the term haicyon
days. The zoologists of two hundred years ago who namcd the genus
were steeped in classical lore, and thought the colonial masses of
,\Icyonium rcsemhled the descriptions of the tangled nest of the fabled
bird, and in fond conceit namcd the genus so. They did redeem
themseives, however, in providing the apt digitatum as the trivial
epitlret, so that thc speciesl name in f'rll is Alcyaniwn diEtatu"tn.
Deacl Men's Fingers form cpntinuous mats with their colonial lobes
projecring from rocks, or any hard substrates, including man-made
structures such as piers or drllllng rigs. They can accclerate corrosicn
on metal structures, and as fouling organisms they increase drag in
moving vessels. The colonies are found from just bclow the lowest tide
leve1s to depths clf 50 metres ot morc. The colonies arc usually pale
veilow or white, and as th"ey waft and sway in the currents look for all
the world like fore sts of cadaverous hands. Each colony consists of sea
anemone-like polyps, called zooids, linked togcther in a gelatinous
mass supported by a loose skclcton of lirnestone spicules. Each zooid
has eight feathery tentacles, which collect detritus falling through the
sea. Alcyonium is a soft coral allicd to the sea pens and sea fans. Unlike
the tropical corals it does ltc)t folm reefs since it is unable to concfetc
its spicuies together to form a massive, rocky skeleton.
Alryonirnn colonics are an important part of the marine fauna as they
form a large part of the biomass of suspension ' feeding cornnunitics'
They play a role in trapping carbon, by cxtracting carbonic acid
(dissolved carbon dioxidc) from the watcf and using it in reaction with
calcium to build up their skeleton, In this way they contribute to
reducing levels of frcc carbon dioxide, and reducc *re acidity of the se a
water. They are sensitive to high temperatures, and die away if the
water becomes too warm. This is, of course, a "double whammy" since
their loss io the environment meatls that less carbon dioxide is trappcd
and the greenhotrse effcct of the increased carbon dioxide leads to
further global warming which in turn reduces the populations of the
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