If we regard as seaweeds the larger, attached marine species of the red, brown and green algae, slightly over 500 different kinds occur in Ireland.

 

	Reds	Browns	Greens	Total
Ireland	274	147	80	501
Scotland	208	137	70	415
England & Wales	311	181	85	577
France	368	193	128	689
North Atlantic	620	329	256	1205

Numbers of seaweed species (red, brown and green) occurring in selected areas and in the whole of the North Atlantic. Data from Guiry (1996, AlgaeBase).

Although more species occur in England and Wales (taken together) than in Ireland, less are found in Scotland, and, considering smallness of the island, we have a remarkably high proportion of the marine algae of the whole of the North Atlantic basin. Many of these algae are relatively obscure species, known only to a handful of experts world-wide. Since 1979, our knowledge of Irish seaweed biodiversity has increased considerably (see Table above), due largely to more widespread subtidal investigations. Extensive taxonomic revisions have resulted in a seeming decrease in the total numbers of green algae, but the large increase in the red algae is mainly due to discoveries of previously unknown species, particularly in the subtidal of the west coast. Further taxonomic studies of our marine algae are needed, particularly of some of the supposedly well-known genera such as Fucus.

• Biomass

Last modified: October 11 2020