The rocky shore is home to many many many species of seaweed. Most of which we people usually just move out of our way to find the ‘cooler’ for interesting animals. But seaweeds as a group are not to be overlooked, they are ecologically important primary producers, they are homes, food and sunshades for a diverse group of rocky shore critters. But if that doesn’t immediately interest you, well then this species should because it also used to make beer and ice creams!
Irish moss is harvested for its Carrageen which has gelling properties. This is super useful in a wide varieties of industries and the list of products its used in is not short, including milk products, canned pet food, mouses, beer clarification, soap, leather, printing, linen, toothpaste and some medicines. So regardless of whether you like rocky shore (which I am assuming yo also do by reading this post) you should like Irish Moss, because it’s very very useful!
Irish Moss under a microscope light showing iridescence.
On the rocky shore your likely to find it on the mid to lower shore, although it can also be found occasionally on the upper shore. Its colour and frond width can vary from shore to shore or even within one shore. When exposed to high levels of sunlight (so higher up the shore) it can turn greeny/brown, but is usually a deep red/brown. Another awesome thing about the colour of Irish Moss is that in rock pools, and this often catches your eye whilst scrambling through pools, is that the frond tips are iridescent. There have been suggestions that this helps protects the seaweed for UV, or it confuses predators but so far is not yet known why this species does this. It however, is very pretty, and its one of the more ‘fun’ seaweeds to go out and hunt on the rocky shore!
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