Biodiversity & Conservation

Green seaweeds (Ulva spp. and Cladophora spp.) in upper shore rockpools



Image Dale Cartlidge - Green seaweeds (Enteromorpha spp. and Cladophora spp.) in upper shore rockpools Image width ca 1m.
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Distribution map

LR.FLR.Rkp.G recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats
  • UK_BAP

Text page icon Habitat description

Map icon Distribution of biotope in Britain and Ireland On rocky coasts around Britain and Ireland.
National importance Widespread

Text page icon Description of biotope

For a full description of this biotope including characterizing species, distribution, survey information and references visit JNCC

Rockpools in the supralittoral, littoral fringe or upper eulittoral which are subject to variable salinity and widely fluctuating temperatures are characterized by the ephemeral green alga Ulva spp. or the filamentous green alga Cladophora spp. Due to the physical stress imposed on these upper shore pools, grazing molluscs are generally in lower abundance than eulittoral pools, allowing the green algae to proliferate under reduced grazing pressures. The rock surface is often covered by the black lichen Verrucaria maura. On more exposed shores crevices in the rock may contain small Mytilus edulis. The bright orange copepod Tigriopus fulvus is tolerant of large salinity fluctuations and may also occur in large numbers in these upper shore pools. (Information taken from the Marine Biotope Classification for Britain and Ireland, Version 97.06: Connor et al., 1997a, b).

Additional information icon Additional information

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This review can be cited as follows:

Budd, G.C. 2002. Green seaweeds (Ulva spp. and Cladophora spp.) in upper shore rockpools. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/11/2015]. Available from: <>