Rocky shores! Flashcards
What is the intertidal section of a rocky shore?
Shoreward fringe of the seabed between highest and lowest extent of the tide.
Define coastal geomorphology
The study of the development and evolution of the coast as it
acts under the influence of interacting physical processes.
Give an example where interactions of different key physical features interact to affect the biota living on rocky shores
Rock type affects temp (dark gets hotter) yet at the same time the height of the tide affects temp too which in turn decides which biota can live there.
Two geological factors of rock deciding what lives there?
rock type - colour (affects temp) and hardness (less hard rocks have more cracks offering refuge from dessication and predation
What causes bio-erosion?
Radula of molluscs and limpets can scratch away rock while feeding or to make firm seal with rockas well as seaweed that can anchor to rock only to be pulled away in strong drag along with rock chunks (Durvillasa Antarctica)
Organisms can also prevent erosion too (Neptunes Lecklace) pads out rocky shore.
How does dessication, temp and salinity change around a rocky shore?
Increases vertically and further from the sea!
Why does drag occur?
Speed of water movement and pressure inversely related.
hence area infront of object has water slowed right down (high press) water swooshing round means low pressure and hence it moves from high to low. Acts PARALEL TO WATER FLOW
Existing body forms to get around drag?
Limpet shell, reduces surface area facing water therefore reducing amount of water being slowed.
Flexible forms - macroalgae, sponges
Weigh up seen in seaweed leading to morphological change?
Larger surface area allows more photosynthesis but greater drag. Hence sheltered areas see fatter ruffled ribbon leaves and exposed are blades.
Why does lift occur?
Water is moving above organism faster than movement below if there is more distance to cover. This means there is movement of particles from the higher pressure slower water to lower pressure faster water. ACTS PERPENDICULAR TO WATER FLOW
How and why does a shark use lift?
Larger fin on top so water has to travel further hence moving at faster speed than water running below. Sharks do not have swim bladder so this allows them to be constantly moving upward.
Why are intertidal zones considered nutrient rich?
Recieve coastal phytoplankton as well as terrestrial run off.
Definition of a keystone species?
Species whose presence greatly decides the presence of other species (either as they provide a habitat - mountain ash, or limit species with predation)
Specialities of higher intertidal animals compared to lower?
Higher - greater tolerance of dessication and extreme temps (eg barnacles) Lower - better at absorbing wave shock (soft bodied anenomes.
Advantage of high and low SA:VOL ratio
Why most higher intertidal organisms go with low (smaller in size)
High - less water loss low - able to release heat
Most have shells so desication is not a problem hence heat loss is most important.
