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 Organism A Distribution on the intertidal Effects of physical factors Organism B Distribution on the intertidal Effects of physical factors

Immersion time Emersion time Temperature & desiccation Wave action Physical Factors on the Intertidal

Barnacle life cycle Nauplius Cyprid Settle Adult Benthic Pelagic

1. Desiccation Barnacle cyprids Foster Mar. Biol. 8: Time (hours) Percentage mortality water loss

1. Desiccation Foster Mar. Biol. 8: Median lethal time (hours) Basal diameter (mm) Balanus crenatus Semibalanus balanoides Elminius modestus

Why are larger animals more resistant to desiccation? 1 cm Surface area = 6 cm 2 Volume = 1 cm 3 2 cm Surface area = 24 cm 2 Volume = 8 cm 3 Ratio = 6:1 Ratio = 3:1

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) Inner Region Middle Region Outer Region Transient species Highest diversity Very few inhabitants Clay, fine silt, sand Gravel, shells, coarse sand

1. DESICCATION Avoiding drying 1. Barnacles - trap water CO 2 O2O2 2. Mussels - Airgape - open valves repeatedly during low tide

1. DESICCATION Coping with oxygen depletion Fucus resubmerge Percentage of initial water retained Percentage of initial water lost O 2 consump- tion

2. TEMPERATURE

METABOLIC RATE ºC INTERTIDAL INVERTEBRATES DEEPER WATER INVERTEBRATES

2. TEMPERATURE Upper Lethal Temperature Median lethal time (hrs) Balanus crenatus S. balanoides Chthalamus

2. TEMPERATURE Upper Lethal Temperature Median lethal time (mins) Asterias Ophioderma Arbacia Uca Ilyanasa

2. TEMPERATURE -effects of substrate and crowding TISSUE ºC EXPOSURE TIME solitary cobble crowded cobble solitary boulder crowded boulder solitary cobble crowded cobble solitary boulder crowded boulder High intertidal Low intertidal

2. TEMPERATURE -effects of shading Surface ºC TIME Canopy removed Under canopy

2. TEMPERATURE Latitudinal effects Helmuth et al, Ecol. Monogr. 2006

Weather for St. Andrews 19 Jan – 1 Feb

2. TEMPERATURE Tolerances within genera LT P. eriomerus P. cinctipes LT 50 = MHT 19 species of Petrolisthes Mean Habitat Temperature (MHT) Somero Int.Comp. Biol. 42:780 P. cinctipes P. eriomerus

2. TEMPERATURE Tolerances within genera Somero Int.Comp. Biol. 42:780 T. funebralisT. brunneaT. montereyi L. sctulataL. keenae

Temperature and Aggregation Chapperon & Seuront J. Therm. Biol 37: 640

Temperature and Aggregation Chapperon & Seuront J. Therm. Biol 37: 640

Temperature and Aggregation Chapperon & Seuront J. Therm. Biol 37: 640

Desiccation and Aggregation Coleman J.Exp.Mar.Biol.Ecol. 386:113 No significant differences

Coleman J.Exp.Mar.Biol.Ecol. 386:113 Desiccation and Aggregation No significant differences

2. TEMPERATURE -low temperature

2. TEMPERATURE -low temperature Dendronotus frondosus (Gionet & Aiken, 1992) % Survivorship 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 Orientation (º to flow)

3. WAVE STRESS b. Holding on - tenacity What is “tenacity”? 1. Suction? Atmospheric pressure ≈ 1 kg/cm 2 Patella ≈ kg/cm 2

3. WAVE STRESS b. Holding on - tenacity What is “tenacity”? Patella

3. WAVE STRESS b. Holding on - tenacity What is “tenacity”? 2. Adhesion F = 2 A S d area surface tension thickness Theoretical adhesion = 600 kg/cm 2

3. WAVE STRESS b. Holding on - tenacity What is “tenacity”? 2. Adhesion F 1d1d Tenacity (kg/cm 2 to detach) Weight of mucous

3. WAVE STRESS a.Limitation of size - plants Laminaria

3. WAVE STRESS - How plants deal with it current Movement of plant – dissipates E Reaction force Inertial force

3. WAVE STRESS -can extend intertidal zones Upper limit of barnacles Upper limit of mussels Upper limit of fucoids Upper limit of kelp ELWS EHWS ExposedSheltered

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 ExposedProtected

Effects on limpet distribution Todgham et al, 1997 Wave Velocity Recorder

Effects on limpet distribution Todgham et al, 1997 Lottia digitalisLottia paradigitalis Lottia pelta Tectura personnaTectura scutum

Effects on limpet distribution Todgham et al, 1997 At each site recorded: 1.Species 2. Size class - Small, Medium, Large 3.Microhabitat a.Bare rock b.Bare rock with barnacles (Balanus) c.On/under algae d.Crevices

Effects on limpet distribution Todgham et al, 1997 SpeciesProtectedExposedP-value Lottia digitalis 50 ± ± 6.44NS L. paradigitalis 18.6 ± ± 2.7NS L. pelta19.6 ± ± 1.44NS Tectura scutum 25.4 ± ± T. personna25.9 ± 3.8Not foundXXXX

Effects on limpet distribution Todgham et al, 1997 Low tideHigh tide L. digitalis L. paradigitalis L. pelta T. personna T. scutum

Effects on limpet distribution Todgham et al, 1997 Wave protected L. digitalis frequency Habitat frequency Bare rock Rock/Barnacle Cover Crevice Bare rock Rock/Barnacle Cover Crevice Wave exposed Lottia digitalis

Effects on limpet distribution Todgham et al, 1997 Distribution of size classes in all species

Effects on limpet distribution Blanchette, 1997 Growth and survival of Fucus gardneri

Effects on Fucus Blanchette, 1997 Growth and survival of Fucus gardneri

Effects on Fucus Blanchette, 1997

Growth and survival of Fucus gardneri Effects on Fucus Blanchette, 1997

Growth and survival of Fucus gardneri March August February Planiform area m 2 Exposed Protected Effects on Fucus Blanchette, 1997

Growth and survival of Fucus gardneri March August February Mean Length Exposed Protected Effects on Fucus Blanchette, 1997

Growth and survival of Fucus gardneri March August February Mean Mass Exposed Protected Effects on Fucus Blanchette, 1997

Transplants Effects on Fucus Blanchette, 1997

Transplants P to P P to E E to P E to E P to P P to EE to P E to E Mean area Maximum area Mean area Sept Effects on Fucus Blanchette, 1997

Transplants P to P P to E E to P E to E Reproductive Status (number of blades with mature receptacles) Effects on Fucus Blanchette, 1997

Next time Intertidal Zonation - Biological Factors