rocky intertidal

ROCKY INTERTIDAL

RELATIVE TIDE LEVELS

RELATIVE TIDE LEVELS

-EFFECT OF SLOPE

MHWS

MHWN

MTL

MLWN

MLWS

ZONES CAN BE SEVERAL TENS OF METRESWIDE

ZONES CAN BE LESS THANA METRE WIDE

RELATIVE TIDE LEVELS

-EFFECT OF SLOPE

Slope and Substrate

SSlope

Substrate Size Wave Action

Slope and Substrate

Steep slope

Strong wave action

Coarse substrate

Water drains at low tide

Gradual slope

Weak wave actionFine substrate

Water retained at low tide

Slope and Substrate

Stephenson and Stephenson Classification of Rocky Intertidal Shores

Stephenson and Stephenson Classification of Rocky Intertidal Shores

a. Supralittoral Zone

Xanthoria

Stephenson and Stephenson Classification of Rocky Intertidal Shores

b. Supralittoral Fringe

Calothrix

Verrucaria

Littorina

Stephenson and Stephenson Classification of Rocky Intertidal Shores

b. Supralittoral Fringe

Bottom of zone

Fucus spiralis Semibalanus balanoides

Stephenson and Stephenson Classification of Rocky Intertidal Shores

c. Midlittoral

- begins at upper limit of barnacles

Stephenson and Stephenson Classification of Rocky Intertidal Shores

c. Midlittoral

4 dominant species

Semibalanusbalanoides-northern rock barnacle

Ascophyllum nodosum - knotted wrack

Stephenson and Stephenson Classification of Rocky Intertidal Shores

c. Midlittoral

4 dominant species

Mytilus edulis-blue mussel

Fucus vesiculosus- bladder wrack

Stephenson and Stephenson Classification of Rocky Intertidal Shores

c. Midlittoral

Other common species

Acmaea-limpet

Littorina littorea-periwinkle

Stephenson and Stephenson Classification of Rocky Intertidal Shores

c. Midlittoral

Other common species

Thais-whelk

Stephenson and Stephenson Classification of Rocky Intertidal Shores

c. Midlittoral

On stalks of Ascophyllum

Sertularia

Flustrellidra

Polysiphonia

Stephenson and Stephenson Classification of Rocky Intertidal Shores

c. Midlittoral

Lower midlittoral

Porphyra

Palmaria

Stephenson and Stephenson Classification of Rocky Intertidal Shores

d. Infralittoral

Laminaria- kelp

Stephenson and Stephenson Classification of Rocky Intertidal Shores

d. Infralittoral

Strongylocentrotusdroebachiensis

Ulva

Stephenson and Stephenson Classification of Rocky Intertidal Shores

d. Infralittoral

Asterias vulgaris

Critical Tide Levels(Doty, 1946)