1. Rocky Intertidal Zone Community

2. Intertidal Zone Area of the shore between the highest high tide and lowest low tide

8. Mixed Semi-diurnal Tidal Regime Two tides per day Tidal heights not equal

9. neap spring FullHalfNewHalf Zero datum (MLLW)

10. A B C Position on Shore

11. Physical Factors Affecting Distributions Physical Tolerances Temperature (average and extreme) Moisture/Desiccation Light Gasses (respiration) Wave shock Sand scouring

12. Biological Factors Biological Interactions Predation Grazing Competition Symbioses

13. Summary Upper distributions of intertidal organisms tend to be determined by physical factors – tolerances Lower distributions of intertidal organisms tend to be determined by biological interactions

14. Intertidal Zonation

17. Factors Affecting Height of the Intertidal Zone Slope of the shore Wave exposure Local geomorphology Tidal flux

27. Behavioral Adaptations

47. Morphological Adaptations Color Shells

53. Physiological Adaptations Quiescence Acclimation Anaerobic Respiration/O 2 Debt Aerial Respiration

56. Latitudinal Submergence

58. Biological Factors Competition Predation Symbioses

59. J. Connell Competition between Balanus balanoides and Chthamalus stellatus

60. Balanus balanoides DISTRIBUTIONS

61. Chthamalus Balanus Transplant TRANSPLANT ADULTS

62. Transplant adults Both Chthalamus and Balanus survive

63. Chthamalus Balanus Clearance BEFORE CLEARANCE EXPERIMENTS

64. Chthamalus Balanus Clearance RESULTS CLEARANCE EXPERIMENTS

65. Clear both Balanus and Chthalamus Both Chthalamus and Balanus recolonize

66. Chthamalus Balanus Clearance CONTINUOUS REMOVAL AND CONTROLS Chthamalus removed CLEARANCE EXPERIMENTS

67. Continuous removal of Chthalamus from both heights Ex. Balanus recolonizes and Chthalamus does not C. Both species recolonize Chthamalus has no effect on Balanus in lower zone

68. Chthamalus Balanus Clearance CONTINUOUS REMOVAL AND CONTROLS Balanus removed CLEARANCE EXPERIMENTS

69. Continuous removal of Balanus from both heights Ex. Chthalamus colonizes in Balanus zone C. Both species recolonize zones Balanus cannot survive in upper zone Chthamalus can survive in lower zone in the absence of Balanus

70. Chthamalus stellatus Balanus balanoides

71. Chthamalus Balanus Clearance

73. Conclusions Balanus exclusion determines lower distribution bound for Chthamalus Competitive interaction responsible Exclusion mechanism is crushing Upper distribution of Balanus determined by physical tolerance

74. R. Paine Predation by Pisaster ochraceus on Mytilus californianus

79. Mytilus californianus Algae Pisaster ochraceus

80. Remove Pisaster No removal BEFORE

81. Remove Pisaster No removal

82. AFTER

83. Conclusions Pisaster determines the lower distribution bound of Mytilus by predation The upper limit of Mytilus distribution determined by physical tolerances