Intertidal zonation

Question 1

who are TA & A stephenson (1949)

Answer 1

they began noticing the pattern of zonation on a global level.

Question 2

what species makes up the upper black banding?

Answer 2

Verracaria

Question 3

What are the three min divisions of the intertidal (littoral) zone?

Answer 3

• supralittoral fringe (upper limit of barnacles to upper limit of periwinkles
• midlittoral zone (middle, broadest in extent, upper limit barnacles, lower is larger kelps)
• infralittoral fringe (lowest low tide, to upper limit of large kelps. limited exposure to air)

Question 4

what is the upper tide limit set by?

Answer 4

strictly by temperature and desiccation, not competition.

Question 5

which acorn barnacle is more dominant in competition in intertidal?

Answer 5

Semibalanus balanoides.

Question 6

How are biological factors more complex than physical factors for causes of zonation? (5 factors)

Answer 6

• competition
• predation
• grazing (herbivory)
• positive interactions
• larval settlement (recruitment)

Question 7

Payne (1966) was best known for what work?

Answer 7

very important coastal ecologist

• barnacle research, sea star research
• coined the term ‘keystone spp’
• uni of washington
• tested his theory in nzealand and chile.
• re-establishing communities.

Question 8

bet hedging, def’n and an example

Answer 8

• change your morphology based upon what your environment looks like
• crustose (upper tidal zone) and foliose (lower tidal zone) kelp.

Question 9

what are algal defenses?

Answer 9

• bet hedging
• reproductive defenses (r-selected, k-selected)
• life history strategies (ie porphyra with two growth forms associated to season)
• geographic dependence

Question 10

what are ‘r-selected’ and ‘k-selected’ reproductive defenses?

Answer 10

r-selected: quick maturity, high output, colonization

k-selected: slower growing, perennial, long lived

Question 11

what are the two growth forms of porphyra, in association to life history strategies

Answer 11

• winter: low grazing, fast growing, highly palatable sheet like morphology
• summer: high grazing, stage that bores into CaCO3 shells to avoid grazers.

Question 12

what are some positive interaction of group living for kelp?

Answer 12

• temperature
• desiccation
• same species or different species
• palatable species can hide under a canopy of unpalatable species.