1. Intertidal Ecology

2. What is the Intertidal Zone? Zone between highest and lowest tide lines Immersed and Emersed Rocky and soft intertidal zones

3. Review: Tides What causes tidal movements? What does it mean to be: Diurnal Semidiurnal Mixed How do tidal movements vary by area? What causes tidal movements? What does it mean to be: Diurnal Semidiurnal Mixed How do tidal movements vary by area?

4. Pattern: Vertical Zonation

9. Processes: What causes the pattern? Upper limit determined by physical factors Exposure Wave shock Lower limit determined by biological factors Competition Predation Recruitment Varies by location and often not totally clear cut

10. Exposure Problems due to emersion: Physical: Dessication Temperature and salinity fluctuation O 2 availability UV radiation Wave shock Biological: Feeding restrictions Inability to hide from predators

11. Dessication Water loss to the air Strategies: “Run and Hide” - crevices, tide pools, moist algae, subtidal, burrowing (soft only) “Clam up” - protective cover seals in moisture (mussels, periwinkles, barnacles) Allow drying out - massive water loss until next tide (seaweed, limpets)

13. Temperature Variation Air vs. Water Adaptations: Higher tolerance Seek shade and moisture Morphology Clumping (ex. Mussels)

14. Other Issues Salinity variation due to rain, evaporation Respiration Gills reduced and/or protected to reduce drying Organisms slow down metabolism Feeding Active when tide is high (reduces risk of exposure)

15. Wave Action Varies based on shoreline F=ma (Where does the force go?) Wave shock and shearing

16. Dealing with Wave Action Shelter Permanent anchorage Holding on Morphology Compact and streamlined Hardened bodies Flexibility

17. Competition - The Battle for Space Open space quickly colonized Strategies: Fast dispersal and settlement Evict competitors Grow on or over competitors

18. Connell experiment Very little difference at settlement Chthamalus range reduced by competition Transplant/Exclusion experiment results: Balanus high = dies Chthamalus low = thrives

19. Eating and Not Being Eaten

21. How are limits set?

23. Rocky Upper Intertidal “Splash zone” Lichens, cyanobacteria, and some algae Periwinkles and limpets Terrestrial predators

24. Rocky Mid-Intertidal Upper areas - gray and rock barnacles Lower limit set by competition and predation Lower areas - mussels and brown algae Lower limit set by predation from sea stars and spiny lobsters

25. Ecological Succession

27. Rocky Lower Intertidal Mostly immersed Dominated by seaweeds Food for grazers, protection from predators Compete with each other Sea urchins, stars, anemones, nudibranchs, fishes

29. Soft-Bottom Intertidal ZSediment accumulation ZUnstable bottom - what kinds of organisms cannot live here? ZSediment composition based on wave mixing ZGravel, sand, mud

34. Importance of Grain Size ZBurrowing (Infauna) or living between grains (Meiofauna) ZWater circulation ZLess dessication ZNeeded for O 2 (no photosynth) ZAmount and type of detritus (coarser has less) ZDual problem with mud: Less water + more detritus to decay = less O 2

35. Feeding