Maerl
Maerl is the pink (live) and white/grey (dead) stuff you can see among the burrowing anemones (Cerianthus lloydii). It is a coralline algae (Phymatolithon calcareum) which increases the complexity of the substratum (sandy seabed) by creating lots of nooks and crannies for other animals to live in, thereby dramatically increasing the biological diversity.
It is considered
uncommon around the British Isles, and is listed on the EC Habitats Directive
Annex Vb (Connor et
al., 1997)*. Maerl beds are currently one of only six soft sediment
biotope complexes under review by the UK Marine SACs Project. This means that
they are considered to be of high conservation interest at the European level,
and a priority feature of candidate marine ‘special areas of conservation’
(SACs).
*Connor, D W,
Dalkin, M J, Hill, T O, Holt, R H F, and Sanderson, W G. (1997). Marine Nature
Conservation Review: marine biotope classification for Britain and Ireland.
Volume 2. Sublittoral biotopes. Version 97.06. No. 230. JNCC Report,
Peterborough. 448 pp.