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Lecture 8 – INTERTIDAL - ZONATION PHYSICAL FACTORS. Studies of intertidal ecology. Descriptive phase. Understand process. Understand interactions. Investigate physiological/genetic/cellular mechanisms. Studies of intertidal ecology. Effects of physical factors. Organism A.
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Lecture 8 – INTERTIDAL - ZONATION PHYSICAL FACTORS
Studies of intertidal ecology Descriptive phase Understand process Understand interactions Investigate physiological/genetic/cellular mechanisms
Studies of intertidal ecology Effects of physical factors Organism A Distribution on the intertidal Effects of physical factors Organism B Distribution on the intertidal
Physical Factors on the Intertidal Emersion time Immersion time Temperature & desiccation Wave action
1. Desiccation Barnacle cyprids 100 50 0 Percentage water loss mortality 0 3 6 9 12 15 18 Time (hours) Foster 1971. Mar. Biol. 8: 12-29
1. Desiccation 12 10 8 6 4 2 0 Balanus crenatus Basal diameter (mm) Elminius modestus Semibalanus balanoides 0 20 40 60 80 100 120 140 Median lethal time (hours) Foster 1971. Mar. Biol. 8: 12-29
Why are larger animals more resistant to desiccation? 1 cm Surface area = 6 cm2 Ratio = 6:1 Volume = 1 cm3 1 cm 1 cm 2 cm Surface area = 24 cm2 Ratio = 3:1 Volume = 8 cm3 2 cm 2 cm
1. DESICCATION A second kind of experiment (Foster ‘71, J. Anim. Ecol. 40:33)
1. DESICCATION A second kind of experiment (Foster ‘71, J. Anim. Ecol. 40:33)
1. DESICCATION Avoiding drying -seeking refuge (Kensler, 1967, Carefoot, 1977) Outer Region Inner Region Middle Region Gravel, shells, coarse sand Clay, fine silt, sand Transient species Very few inhabitants Highest diversity
1. DESICCATION Avoiding drying 1. Barnacles - trap water CO2 O2 2. Mussels - Airgape - open valves repeatedly during low tide
1. DESICCATION Coping with oxygen depletion Fucus resubmerge 100 Percentage of initial water retained O2 consump-tion 50 100 Percentage of initial water lost
2. TEMPERATURE DEEPER WATER INVERTEBRATES METABOLIC RATE INTERTIDAL INVERTEBRATES ºC
2. TEMPERATURE Chthalamus 40 35 30 Upper Lethal Temperature S. balanoides Balanus crenatus 1 2 5 10 20 50 Median lethal time (hrs)
2. TEMPERATURE 45 40 35 30 Ilyanasa Upper Lethal Temperature Uca Arbacia Ophioderma Asterias 50 100 Median lethal time (mins)
2. TEMPERATURE -effects of substrate and crowding solitary cobble High intertidal crowded cobble TISSUE ºC solitary boulder crowded boulder solitary cobble Low intertidal crowded cobble solitary boulder crowded boulder EXPOSURE TIME
2. TEMPERATURE -effects of shading 40 Canopy removed Surface ºC Under canopy 10 TIME
2. TEMPERATURE Latitudinal effects Helmuth et al, Ecol. Monogr. 2006
2. TEMPERATURE Tolerances within genera 19 species of Petrolisthes 45 40 35 30 25 20 • • • • • • • • P. cinctipes LT50 • • • • • P. cinctipes • • • P. eriomerus LT50 = MHT 10 20 30 40 50 P. eriomerus Mean Habitat Temperature (MHT) Somero. 2002. Int.Comp. Biol. 42:780
2. TEMPERATURE Tolerances within genera L. sctulata L. keenae T. funebralis T. brunnea T. montereyi Somero. 2002. Int.Comp. Biol. 42:780
Temperature and Aggregation Chapperon & Seuront. 2012. J. Therm. Biol 37: 640
Temperature and Aggregation Chapperon & Seuront. 2012. J. Therm. Biol 37: 640
Temperature and Aggregation Chapperon & Seuront. 2012. J. Therm. Biol 37: 640
Desiccation and Aggregation No significant differences Coleman 2010. J.Exp.Mar.Biol.Ecol. 386:113
Desiccation and Aggregation No significant differences Coleman 2010. J.Exp.Mar.Biol.Ecol. 386:113
2. TEMPERATURE -low temperature
2. TEMPERATURE -low temperature Dendronotus frondosus (Gionet & Aiken, 1992) 100 50 0 % Survivorship 0 -4 -8 -10 -12 Temperature (4 hr exposure)
3. WAVE STRESS a. Limitation of size Water flow 100% 90% Boundary layer
3. WAVE STRESS a. Limitation of size Water flow
3. WAVE STRESS b. Holding on Keyhole limpet
3. WAVE STRESS b. Holding on - body orientation Water flow
3. WAVE STRESS b. Holding on - body orientation <.5 m/s >.5 m/s Freq -90 0 90 -90 0 90 Orientation (º to flow)
3. WAVE STRESS b. Holding on - tenacity What is “tenacity”? 1. Suction? Atmospheric pressure ≈ 1 kg/cm2 Patella ≈ 5 - 7 kg/cm2
3. WAVE STRESS b. Holding on - tenacity What is “tenacity”? Patella
3. WAVE STRESS b. Holding on - tenacity What is “tenacity”? 2. Adhesion area 2 AS d surface tension F = thickness Theoretical adhesion = 600 kg/cm2
3. WAVE STRESS b. Holding on - tenacity What is “tenacity”? 2. Adhesion 1 d F Tenacity (kg/cm2 to detach) Weight of mucous
3. WAVE STRESS • Limitation of size - plants Laminaria
3. WAVE STRESS - How plants deal with it current Movement of plant – dissipates E Inertial force Reaction force
3. WAVE STRESS -can extend intertidal zones Exposed Sheltered EHWS Upper limit of barnacles Upper limit of mussels Upper limit of fucoids ELWS Upper limit of kelp
Effects on limpet distribution Todgham et al, 1997
Effects on limpet distribution Todgham et al, 1997 HYPOTHESES 1. Greater density of limpets the wave-exposed site. 2. Limpets will be found more frequently in habitats with refuges. 3. Limpets will be found less frequently in wave protected habitats with refuges.
Effects on limpet distribution Todgham et al, 1997 Habitats Exposed Protected
Effects on limpet distribution Todgham et al, 1997 Wave Velocity Recorder
Effects on limpet distribution Todgham et al, 1997 Lottia digitalis Lottia paradigitalis Lottia pelta Tectura personna Tectura scutum
Effects on limpet distribution Todgham et al, 1997 At each site recorded: Species 2. Size class - Small, Medium, Large • Microhabitat • Bare rock • Bare rock with barnacles (Balanus) • On/under algae • Crevices
Effects on limpet distribution Todgham et al, 1997