Zonation

What are the different zones on the shore?

What two species are dribble spawners and what does that mean?

• Fucus and Postelisa releases gametes onto the rock when the tide first returns

How do bands form?

• spores mix by crashing waves

• biotic and abiotic stressors prune back populations restricting their distributions

• leave behind banded zonation pattern

What defines the upper limit of speceis?

primarily abiotic

• high light

• high temperature

• low/freezing temperatures

• snow/ice

• high desiccation stress

• osmotic shock from rain

• limited access to nutrients

• wave action (higher upper limits where waves splash)

What defines the lower limit of a species?

primarily biotic:

• herbivore grazing

• competition

• fouling y other algae (diatoms, epiphytes)

• desiccation cleaning- get overgrown easier

some abiotic factors:

• light quality

When the tide recedes, how might algae resist light stress?

• adjust pigmentation

• calcification

• grow in the shade, crevice, or under another organism

When the tide recedes, how might algae resist desiccation stress?

• saccate morphology (halosaccion)

• turf morphology (corallina vancouveriensis)

• cell wall polysaccharides retain water

• — red: carrageenans and agarans

• — brown: alginates

• dry out then rehydrate

what does low tide (midday) in the summer expose algae to?

bright sun, desiccation, and thermal stress

what does low tide (midday) in the winter expose algae to?

low temperatures, osmotic stress, snow fall

What is the equation for measuring seaweed hight?

seaweed height = tide height + beam height - laser

How do Endocladia use desiccation to resist temperature stress?

leave behind “fairy rings”