Biodiversity & Conservation

Ruppia maritima in reduced salinity infralittoral muddy sand



Image Anon. - Ruppia maritima in reduced salinity infralittoral muddy sand. Image width ca 40 cm.
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Distribution map

SS.SMp.SSgr.Rup recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

Recorded distribution in Britain and Ireland

Ruppia beds have a scattered distribution, dependant on available habitat, with concentrations in the Cromarty Firth, the Fleet, and lagoonal habitats of west Scotland, Orkney and Shetland. This biotope was not recorded in Ireland.

Habitat preferences

Temperature range preferences - 10 -30 °C (see additional information).

Water clarity preferences - Very high clarity / Very low turbidity
High clarity / Low turbidity

Limiting Nutrients - Nitrogen (nitrates)
Phosphorus (phosphates)

Other preferences - See additional information.

Additional information

Ruppia communities, as IMS.Rup were reported as uncommon in the MNCR (Connor et al., 1997a). However, the MNCR may have under recorded its occurrence, since more records are given, as NVC SM2, by Rodwell (2000).

Habitat preferences

  • Wave sheltered soft sediments with weak tidal streams.
  • Ruppia spp. occur at depths between 0-4.5m depending on turbidity and the tendency for the substratum to be re-suspended, i.e. only occurring at shallow depths (<1.5m) on fine, clay sediments but 2.0m or more on sand or shell substratum.
  • Ruppia spp. require high levels of light when compared to eelgrass, and therefore, require clear water, e.g. turbidities <25-55 ppm suspended sediment were recommended for wetland management of Ruppia beds while Ruppia spp. have been reported in waters with 17.5-42.5 ppm suspended sediment.
  • Ruppia spp. survive water temperatures of 0 -38 °C but grow exponentially between 10-30°C.
  • Ruppia spp. tolerate the widest range of salinities of any aquatic angiosperm and Ruppia maritima can occur in waters of 0.6 to 390g /l dissolved solids but grows best in culture between 4.7 -22.6 psu.
  • Ruppia spp. occur in water of pH 6.0 -10.4 but may have an affinity for waters of pH 7.7 -9.4.
Data from Verhoeven (1979) and Kantrup (1991).

This review can be cited as follows:

Tyler-Walters, H. 2001. Ruppia maritima in reduced salinity infralittoral muddy sand. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 27/11/2015]. Available from: <>