Diarmuid Breatnach
(Reading and viewing time: 3 mins)
On a sunny but windy day in Greystones, lá grianmhar ach gaofar, nature put on an abstract art show. The sunshine brought out intensely the yellow of the lichen on the limestone rocks, while the black lichen encrustation on some rocks contrasted sharply with a neighbouring section of bare grey. Some trick of the camera and light brought out a gorgeous blue in the rock-shadowed sea which had not been visible to the eye.
Lichens are an amazing life form, being an integrated symbiosis of an alga and a fungus. A cross between a frog and a goose would not be more bizarre in concept – fungi are not even plants, while algae are. The fungus provides a relatively strong skeleton while through photosynthesis the alga produces sugars to feed the fungus.
Although not all are easy to distinguish, there are over 1,165 species of lichen in Ireland, varying from the common to the rare. The yellow-orange one, Xanthoria parietina, is one of the common ones in Ireland. The white and often off-white or grey Ochrolechia parella can be mistaken for bird excreta at a distance, or even as the ground-in chewing gum that costs Dublin City Council so much to remove from street surfaces every week. The black one, Verrucaria maura if I am identifying it correctly, covers rocks that are wave-lapped or hit by sea-spray on a daily basis.
These are all hardy adventurers, extremophiles, living in zones exposed to great variations of temperature, all even in one day, as the sun beats down between rain showers or windy spray. And they are very tolerant of salinity, without at the same time being dependent upon it. Perhaps not these species but their ancestors, or other forms like them, were the early colonisers of the land on our planet. Terraformers too, as they slowly abrade the rock upon which they cling, helping to create soil, while black lichen attracts heat to warm up surfaces and the alga in the symbiotes releases oxygen into the atmosphere.
Lichens can live attached to rock, wood and metal, some species even inside stone and on snow.
No plaque or monument celebrates these hardy adventurers but down on the harbour wall was a plaque to another hardy life-form, celebrating the 1910 confrontation there of Chief Secretary Birrell, one of the Crown’s main representatives in Ireland, by Hannah Sheehy-Skeffington and Hilda Webb. They were kick-starting the militant Votes for Women campaign which was later brought into conflict with the Irish Parliamentary Party too but influenced the 1916 Proclamation’s advanced and stirring address: “Irishmen and Irishwomen ….”. That Rising six years after the Greystones confrontation would shock Birrell and sadly, would see Hannah’s pacifist husband Francis murdered by a British Army officer during that momentous week.
Earlier, in a Dublin train station, I photographed a wall of varied limestone, where algae and moss, also terraformers, had made an abstract art collage.
End.
REFERENCES
http://www.biology.ie/species.php?m=lichens-ie&s=2140
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