The Shore Thing Project

www.marlin.ac.uk/shore_thing

ROCKY SHORE ECOLOGY

ROCKY SHORE ECOLOGY

• Tides are caused by the gravitational pull of the moon and sun

• There are generally two tidal cycles in 24 hrs

• The rise and fall of the tide varies depending on whether it is a neap or spring tide

• Tidal range varies around the UK coast.

TidesTides

The Rocky Shore EnvironmentThe Rocky Shore Environment

• All species specially adapted• Marine and terrestrial• Exposure high• Changing conditions• Different zones on the shore• Location important for

identification

Upper shore

Lower shore

Desiccation

Salinity variation

Temperature variation

Light

Exposure

Feeding time

Environmental VariationsEnvironmental Variations

‘‘Splash’ ZoneSplash’ Zone

•Extremely exposed•Salt spray•Conditions extremely variable•Dominated by lichens•Rarely submerged

Upper shoreUpper shore

•Very exposed•Conditions very variable•Diversity low dominated by

channelled wrack and small periwinkles

•Submerged for short periods•Exposed for long periods

Middle shoreMiddle shore

• Moderately exposed• Conditions moderately

variable• Dominated by fucoids,

barnacles, molluscs and gastropods

• Species depends on exposure

• Submerged and exposed every tide

Lower ShoreLower Shore

• Less exposed

• Conditions relatively stable

• High diversity of specially adapted marine species

• Dominated by kelps, red algae, sea squirts and sponges

• Submerged most of the time, only exposed on low spring tides

Major groups/phylum of species are:• Algae (seaweeds)• Lichens• Marine Invertebrates (animals without backbones)

• Porifera (sponges)• Cnidaria (anemones/jellyfish/hydroids)• Crustacea (crabs/barnacles)• Mollusca (top shells/limpets)• Echinoderms (sea urchins/starfish)

• Marine Chordates (animals with backbones)• Tunicates (sea squirts)• Fish

Rocky Shore IdentificationRocky Shore Identification

•Brown – Wracks and Kelps•Green •Red – includes encrusting algae•Flowering plants such as seagrass

Marine AlgaeMarine Algae

• Fungus and algae living together in symbiosis• Often an encrusting layer on rocks • Found in the splash zone

LichensLichens

•Porifera - Sponges– Attached to surfaces– Very simple animals, covered with pores– Rounded or branched forms– Often need microscope to identify them

Marine InvertebratesMarine Invertebrates(animals without backbones)(animals without backbones)

• Cnidaria - Anemones, corals, hydroids and jellyfish– ‘Mouth’ surrounded by tentacles– Attached and free swimming forms– Sometimes forming large colonies

• Crustacea - Crabs, lobsters, shrimps etc.– Segmented body covered in hard plates– Divided into three segments– Jointed limbs– Adapted to live in every marine environment

• Mollusca - Snails, bivalves, chitons, limpets, sea slugs etc. – Largest most diverse group– Gastropods have large muscular foot– Bivalves body surrounded by two shells held together with

a hinge

•Echinoderms - Starfish, sea urchins, sea cucumbers and brittlestars

–Tube-feet, internal skeleton of bony plates–Often external skeletons

• Tunicates – Star of ascidian and sea squirts– Larval stage has a backbone– Two openings body covered in ‘tunic’ of jelly– Colonies sometimes confused with sponges

Marine ChordatesMarine Chordates(animals with backbones)(animals with backbones)

• Fish – Shanny, blenny, rockling, clingfish etc.– Divided into two main groups, elasmobranchs (sharks, rays etc)

and teleosts (bony fish)– Elasmobranchs have a skeleton of cartilage– Teleosts skeleton is bony

Key FeaturesKey Features

Cone shaped shell, up to 2.5 cm high

Tooth on inside of mouth opening

Shell grey-green

Shiny ‘mother of pearl’ inside shell opening

Bushy brown seaweed

Covered in what looks like small leaves and tiny round floats

Very dense, feels coarse and wiry

May form long lengths (like a washing line)

1

Prominent midrib

Pairs of almost spherical gas bladders

Dark olive brown

Up to 1 m long

Large round hole on underside of the shell

Dull greenish in colour with reddish-purple broad diagonal stripes

Small top shell 1.6 am high. 2.2 cm across

2

3 4

• Cone shaped shell, up to 2.5 cm high• Tooth on inside of mouth opening• Shell grey-green • Shiny ‘mother of pearl’ inside shell opening

H

Osilinus lineatus

Species No. 1Species No. 1

• Bushy brown seaweed• Covered in what looks like small leaves and tiny round

floats• Very dense, feels coarse and wiry• May form long lengths (like a washing line)

D

Sargassum muticum

Species No. 2Species No. 2

• Prominent midrib• Pairs of almost spherical gas bladders• Dark olive brown• Up to 1 m long

F

Fucus Vesiculosus

Species No. 3Species No. 3

• Small round hole on underside of the shell• Dull greenish in colour with reddish-purple

broad diagonal stripes• Small top shell 1.6 cm high. 2.2 cm across

C

Gibbula umbilicalis

Species No. 4Species No. 4