|Basic Information||Biotope classification||Ecology||Habitat preferences and distribution||Species composition||Sensitivity||Importance|
Image Sarah Fowler - Maerl bed in Loch Gairloch, Highland. Image width ca 2 m in foreground.
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SS.SMp.Mrl.Pcal.Nmix recorded () and expected () distribution in Britain and Ireland (see below)
Temperature range preferences - 10-20 °C.
Water clarity preferences - High clarity / Low turbidity
Very high clarity / Very low turbidity
Limiting Nutrients - Calcium
Other preferences - See additional information.
Growth of Phymatolithon calcareum ceases at 5 degrees C and is optimal at 15 degrees C (typically higher than water temperatures found around the British Isles). Growth of Phymatolithon calcareum is impaired at salinities below 24 psu (King & Schramm, 1976) so the species is absent from areas with variable or reduced salinity. Distribution of maerl is dependent on several factors. Living maerl has poor tolerance of desiccation and so is typically found subtidally (Hall-Spencer, 1998). As a photosynthesising organism there is a requirement for light which restricts the species to depths shallower than 32m in the relatively turbid waters of northern Europe (Hall-Spencer, 1998). Some shelter from wave action is required to prevent physical damage, dispersal or burial although some degree of water movement is important to ensure that silt does not smother the maerl bed. King & Schramm, (1982) report that ionic calcium concentration is the main factor affecting growth of maerl in culture experiments rather than salinity per se (although this has not been shown in the field). Uptake of calcium carbonate occurs optimally at 30 psu.
This review can be cited as follows:
Jackson, A. 2006. Phymatolithon calcareum maerl beds with hydroids and echinoderms in deeper infralittoral clean gravel or coarse sand. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 07/10/2015]. Available from: <http://www.marlin.ac.uk/habitatpreferences.php?habitatid=64&code=2004>