1. Lecture 7 ROCKY INTERTIDAL

2. RELATIVE TIDE LEVELS

3. -EFFECT OF SLOPE MHWS MHWN MTL MLWN MLWS ZONES CAN BE SEVERAL TENS OF METRES WIDE ZONES CAN BE LESS THAN A METRE WIDE

4. RELATIVE TIDE LEVELS -EFFECT OF SLOPE

5. Slope and Substrate SSlope Substrate Size Wave Action If you know any two factors, you can determine the third.

6. Slope and Substrate Steep slope Strong wave action Coarse substrate Water drains at low tide Gradual slope Weak wave action Fine substrate Water retained at low tide

7. Slope and Substrate Decreasing sediment size

8. Slope and Substrate High wave/ steep slope

9. Slope and Substrate Low wave/ gentle slope

10. Stephenson and Stephenson Classification of Rocky Intertidal Shores EHWS ELWS Infralittoral Upper limit - Laminaria Mytilus Ascophyllum Barnacles Upper limit - Barnacles Upper limit - Littorina Infralittoral fringe Midlittoral Supralittoral fringe Supralittoral After Stephenson & Stephenson (1949)

11. Stephenson and Stephenson Classification of Rocky Intertidal Shores a. Supralittoral Zone Xanthoria

12. Stephenson and Stephenson Classification of Rocky Intertidal Shores b. Supralittoral Fringe Calothrix Verrucaria Littorina

13. Stephenson and Stephenson Classification of Rocky Intertidal Shores b. Supralittoral Fringe Bottom of zone Fucus spiralis Semibalanus balanoides

14. Stephenson and Stephenson Classification of Rocky Intertidal Shores c. Midlittoral - begins at upper limit of barnacles

15. Stephenson and Stephenson Classification of Rocky Intertidal Shores c. Midlittoral 4 dominant species Semibalanus balanoides -northern rock barnacle Ascophyllum nodosum - knotted wrack

16. Stephenson and Stephenson Classification of Rocky Intertidal Shores c. Midlittoral 4 dominant species Mytilus edulis -blue mussel Fucus vesiculosus - bladder wrack

17. Stephenson and Stephenson Classification of Rocky Intertidal Shores c. Midlittoral Other common species Acmaea -limpet Littorina littorea -periwinkle

18. Stephenson and Stephenson Classification of Rocky Intertidal Shores c. Midlittoral Other common species Thais -whelk

19. Stephenson and Stephenson Classification of Rocky Intertidal Shores c. Midlittoral On stalks of Ascophyllum Sertularia Flustrellidra Polysiphonia

20. Stephenson and Stephenson Classification of Rocky Intertidal Shores c. Midlittoral Lower midlittoral Porphyra Palmaria

21. Stephenson and Stephenson Classification of Rocky Intertidal Shores d. Infralittoral Laminaria - kelp

22. Stephenson and Stephenson Classification of Rocky Intertidal Shores d. Infralittoral Strongylocentrotus droebachiensis Ulva

23. Stephenson and Stephenson Classification of Rocky Intertidal Shores d. Infralittoral Asterias vulgaris

25. Critical Tide Levels (Doty, 1946. Ecology 27: 315-328 ) Length of maximum submergence Tide level Critical tide levels

26. (Doty, 1946. Ecology 27: 315-328 ) Doty – Algal distributions

27. Druehl & Green, 1982. Mar.Ecol. Prog Ser. 9: 163 More realistic data on submergence

28. Druehl & Green, 1982. Mar.Ecol. Prog Ser. 9: 163

29. Next time Intertidal Zonation – Physical Factors