Intertidal zone

Question 1

Why is the intertidal zone studied?

Answer 1

• smallest area of the world’s oceans
• narrow fringe
• accessible
• variation
• diversity

Question 2

What are physical aspects affecting the intertidal zone?

Answer 2

• tides
• temperature ranges
• wave action
• salinity ranges

Question 3

Define ‘tide’

Answer 3

periodic, predictable rise and fall of sea level over a given time interval

Question 4

Where are some areas of the ocean which do not experience tides?

Answer 4

• mediterranean
• black sea
• baltic sea

Question 5

Describe the gravitational attraction of tides

Answer 5

the tides are attracted to the gravitational pull of the sun and the moon. The moon has 2x more of an attraction than the sun.

Question 6

heliocentrism

Answer 6

means ‘sun center’. Revolve around the sun, not the earth.

Question 7

explain how the gravitational and centrifugal forces work with tides and the earth

Answer 7

• grav. force on the moon side of the earth. Water at ocean basins pulled into bulges. makes high tide.
• centri. force on the opposite side. pulls the water into a bulge away from the earth, creating a high tide.
• gf>cf moon side of earth, gf

Question 8

are there always four tides per day?

Answer 8

nope. there are different angles and magnitudes.

Question 9

What are the ecological effects of tides?

Answer 9

• length of exposure (desiccation, feeding)
• time of day (exposure to air, lethal)
• predictability (rhythms, spawning times)
• temperature (extremes)

Question 10

what are physical parameters affecting the intertidal zone?

Answer 10

• temperatures (extremes, from 0-40 ish. fluxuates way more than the ocean)
• mechanical effects (smashes and tears, loose sediments, adaptations, brings in /takes out food)
• wave action (extends intertidal)
• salinity (exposed at low tide, flooded by heavy rains)

Question 11

How does wave action affect the intertidal zone?

Answer 11

• smashes and tears
• moves loose sand and gravel
• organisms need to adapt
• brings in food, oxygen, others

Question 12

how do organisms adapt to the intertidal?

Answer 12

• water loss resistance: move, find refuge (density, canopy), thick outer cells
• reduction mechanisms: impermeable shells, opercula, close shells at low tide, home scars, mucus, burrow

Question 13

How do intertidal organisms protect themselves against tempertature?

Answer 13

• color of shell (light/dark, hot/cold)
• shape (sculpted/smooth)
• large body size (tropical)
• hold extra water, limpet scars, mantle.

Question 14

how do organisms protect themselves against the mechanical stress in the intertidal zone?

Answer 14

• flexible
• size and shape (squat bodies)
• strong foot
• permanent attachment
• strong temporary (byssal threads)
• behavioral.

Question 15

Respiratory in the intertidal

Answer 15

• gills are thin walled body extensions
• enclosed in a protective cavity
• reduced gills in high intertidal organisms
• behavioral adaptations (close operculum, clamp down)

Question 16

how do intertidal organisms feed?

Answer 16

• restricted by tides, often nocturnal

- must expose fleshy body parts to feed, desiccation

Question 17

Tide synchronized reproduction: Mytilus
______ tide maturation
_______tide broadcast

Answer 17

spring=maturation

neap=broadcast

Question 18

Which coast is older? which has more diversity?
what is its dominant shore-type?
temperature range?

Answer 18

Atl. older, less variation, eroding sediment, lower range 0-25C
Pac younger, more variation, dominated by rock, higher range 20-40cC

Question 19

which coast has older organisms? why?

Answer 19

pac has older organisms, they migrated south. atl has annual ice kills, often spp are mass extinction