Lecture 8 –INTERTIDAL - ZONATION

PHYSICAL FACTORS

1. DESICCATION

Experiment (Frank, 1965. Ecol. 46: 831)

Barnacle

Fucus

Before artificial seep

1. DESICCATION

Experiment (Frank, 1965. Ecol. 46: 831)

After artificial seep

Barnacle

Fucus

Before artificial seep

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 CO2

O2

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

O2 consump-tion

100

50

100

2. TEMPERATURE

2. TEMPERATURE

2. TEMPERATURE

METABOLIC RATE

ºC

INTERTIDAL INVERTEBRATES

DEEPER WATER INVERTEBRATES

2. TEMPERATURE

Upper Lethal Temperature

Median lethal time (hrs)

40

35

30

Balanus crenatusS. balanoides

Chthalamus

1 2 5 10 20 50

2. TEMPERATURE

Upper Lethal Temperature

Median lethal time (mins)

45

40

35

30

50 100

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 cobblesolitary boulder

crowded boulder

High intertidal

Low intertidal

2. TEMPERATURE-effects of shading

Surface ºC

TIME

40

10

Canopy removed

Under canopy

2. TEMPERATURELatitudinal effects

Helmuth et al, Ecol. Monogr. 2006

2. TEMPERATURE-low temperature

2. TEMPERATURE-low temperature

Dendronotus frondosus(Gionet & Aiken, 1992)

%Survivorship

Temperature (4 hr exposure)

0 -4 -8 -10 -12

100

50

0

3. WAVE STRESS

a. Limitation of size

Water flow100%

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

-90 0 90 -90 0 90

>.5 m/s

Freq

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

F = 2 A Sd

area

surface tension

thickness

Theoretical adhesion = 600 kg/cm2

3. WAVE STRESS

b. Holding on - tenacity

What is “tenacity”?

2. AdhesionF 1

d

Tenacity(kg/cm2 to detach)

Weight of mucous

3. WAVE STRESS

a. Limitation of size- plants

Laminaria

3. WAVE STRESS

- How plants deal with it

currentMovement 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 kelpELWS

EHWS

Exposed Sheltered

Effects on limpet distributionTodgham et al, 1997

Effects on limpet distributionTodgham 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 distributionTodgham et al, 1997

Habitats

Exposed Protected

Effects on limpet distributionTodgham et al, 1997

Wave Velocity Recorder

Effects on limpet distributionTodgham et al, 1997

Lottia digitalis Lottia paradigitalis Lottia pelta

Tectura personna Tectura scutum

Effects on limpet distributionTodgham et al, 1997

At each site recorded:

1. Species

2. Size class - Small, Medium, Large

3. Microhabitata. Bare rockb. Bare rock with barnacles (Balanus)c. On/under algaed. Crevices

Effects on limpet distributionTodgham et al, 1997

Species Protected Exposed P-value

Lottia digitalis

50 ± 7.3 62.4 ± 6.44 NS

L. paradigitalis

18.6 ± 3.7 28.0 ± 2.7 NS

L. pelta 19.6 ± 3.33 18.7± 1.44 NS

Tectura scutum

25.4 ± 3.11 33.9 ± 2.88 0.009

T. personna 25.9 ± 3.8 Not found XXXX

Effects on limpet distributionTodgham et al, 1997

Low tideHigh tide

L. digitalis

L. paradigitalis

L. pelta

T. personna

T. scutum

Effects on limpet distributionTodgham 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 distributionTodgham et al, 1997

Distribution of size classes in all species

Effects on limpet distributionBlanchette, 1997

Growth and survival of Fucus gardneri

Effects on Fucus Blanchette, 1997

Growth and survival of Fucus gardneri

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 m2

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 PP to E

E to PE to E

P to PP to E E to P

E to E

Mean area

Maximum area

Mean area

Sept Sept

Effects on Fucus Blanchette, 1997

Transplants P to PP to E

E to PE to E

Reproductive Status(number of blades with

mature receptacles)

Effects on Fucus Blanchette, 1997

Next time

Intertidal Zonation - Biological Factors