Shore ecosystems Intro Flashcards
Biggest Stress of Intertidal Communities
The wet to dry gradient
Environmental Variables in the shore (2)
Sediment Size and wave exposure
The wet to dry gradient (and the cycles of submersion and emersion by the tides)
Sediment size and classification (9)
Boulders: 256mm and up Cobbles: 64-255mm Pebbles: 4-64mm Granules: 2-4mm Coarse sand:0.5-2mm Medium Sand: 0.25-0.5mm Fine Sand: 0.06-0.25mm Silt: 0.004-0.06mm Clay: <0.004mm
Why are middle substrate sizes not suitable for life?
They are too coarse to burrow into, and they shift and move too much to attach to
Relationship of particle size to water velocity
Faster water velocity and more wave exposure brings in larger particles
Sheltered beaches have smaller particle sizes
Mixed semi-diurnal tides
These have 2 high tides and 2 low tides every tidal cycle, but the size of the high and low tides differ
Major problems for organisms caused by tidal cycle (4)
Temperature fluxes
Desiccation
Oxygen deprivation
Cause items to move
Intertidal temperature fluctuations (5)
Day vs Night Seasonal cycles Latitudinal gradients Long term temperature fluctuations (El-Nino/La-Nina) Climate Change
Q10 Rule
Metabolic rate doubles or triples with every 10 degrees C in temperature
Temperature Problems (3)
As temperature increases, the scope of growth is reduced
At supra-optimal temperatures, enzymes begin to fail
At low temperatures: severe energy limitation and growth reduction, risk of freezing
Strategies for dealing with temp. fluctuations (3)
Behavioural: short-term behavioural or ecological change to maintain the internal temperature
Physiological/Biochemical acclimation: A short-term physiological response to changes in temperature
Adaptation: Morphological or physiological feature that evolved to minimize temperature fluctuation
Shell morphology for temp. fluctuations
Light coloured shells reflect heat, ridges on shells enhance the ability to radiate heat
