coastal ecosystems - of the world Flashcards
what is an ecosystem?
An ecosystem is a community of plants and animals which interact with each other and their none living environment.
what is biodiversity?
biodiversity is the number and variety of living species found in a given area or ecosystem.
4 types of ecosystems we have looked at:
- Coral reefs
- mangroves
- salt marshes
- sand dunes
information about coral reefs:
where are they found?
what are they made off?
coral reefs are built up entirely from living organisms, resulting in huge deposits of calcium carbonate (limestone).
Their global distribution is between the tropics (23.5 north and south of the equator)
what are 4 factors that control GLOBAL coral reefs distribution?
- temperature - minimum temp. of 18 C°. Best grow in 23C°and 25C°.
- Light - needed for coral to grow, therefore live in shallow water.
- Water Depth - because of the need of light corals grow where the sea is less than 25m deep.
- Salinity - they can only live in salt water as they are marine creatures.
3 LOCAL factors that are also important in coral reefs:
- Wave action - corals need well oxygenated water, this occurs in areas of wave action.
- Exposure to air - corals cant be exposed to too much oxygen for too long if not they will die.
- sediment - corals need clean clear water, any sediment in the water will block their normal ways of feeig and reduces the amount of light.
information about Mangroves:
where are they found:
Adaptations:
- mangroves are most common in SE Asia, mostly within 30° latitude of the equator.
- mangroves literally live on the coastline in the intertidal zone. they are regularly flooded by the sea and during periods of high rainfall (fresh water)
ADAPTATIONS - they need to with stand brackish water
- they must tolerate great heat and choking mud
- they range in size from little shrubs to trees over 60m iin height.
- they use complex filtration system to keep excess salt out .
- the root system is adapted to the intertidal zone
buttress roots help stabilize the plants. - fruits and seedlings float in the water and are transported by wind and currents. they are then trapped by mud, where they start to grow.
what is brackish water?
brackish water is a mixture of salty water and fresh water
what is the intertidal zone?
the intertidal zone is the area between the high tide and low tide mark.
information about salt marshes:
where are they found?
info:
salt marshes are fond between mud flats (permanently under water) and land (terrestrial) vegetation (above the high tide mark)
- they are also found in the intertidal zone
- coastal salt marshes develop in sheltered areas eg. behind a spit or in an estuary)
- in a bay (behind a spit) the water will be salty
- in an estuary the water will be brackish
TYPES OF ANIMALS AND PLANTS FOUND DETERMINE BY: - salinity levels
- frequency of flooding
- extent (amount) of flooding
salt marshes often contain meandering creeks (streams), which allows the marsh to easily drain tidal water in and out. the creeks and vegetation slow down wave energy, which allow silt and mud to be deposited. consequently, over time, the salt marsh extends sea wards.
what are sand dunes?
coastal sand dunes are accumulation of sand, shaped into hills and ridges by the winds.
where do sand dunes best develop?
they best develop in wide beaches with large amounts of sand. - prevailing wind is onshore
how sand dunes form?
when a beach dries out at low tides, the wind blows some sand into the back of the beach by inshore wind. then sand accumulates around a small obstacle.
accumulation grows and small sand dune is formed. +
continuous to grow and becomes more stable. +
over time vegetation grows on sand dunes and the vegetation fixes the sand dune.
what conditions do plants that grow on sand dunes have to deal with?
salinity
lack of moisture
wind
temporarily submerged by wind-blown sand.
what is PLANT SUCCESSION?
this is when some plants have become well established, environmental conditions will improve and other plants begin to appear. eventually in some areas, dune heath (small bushes) will be established. this whole sequence is known as PLANT SUCCESSION.
