The organisms that are found within the mangrove ecosystem have to be able to adapt to the different salinity levels that occur as a result of weather patterns and human impact.
The species that were mainly studied at Homebush Bay are halophytes, meaning that they are salt tolerant.
MANGROVES:
- Grey mangroves have leaves with glands that excrete salt
- Some species such as the Grey Mangrove can also tolerate the storage of large amounts of salt in their leaves. (discarded of when the levels are too high)
- Mangroves can restrict the opening of their stomata. Allows the mangrove to preserve fresh water, vital to survive in a saline environment.
- Able to turn their leaves to reduce exposure to the sunlight (reduces water loss as a result of evaporation)
- The pneumatophores allow the plant to breath, however also change in size to stop the intake of salt from the water.
- accumulation/storage—in some mangroves, salt accumulates in selected parts of the plant, for example in some leaves, until it reaches a certain concentration. That part of the plant is then shed.
- excretion— salt glands on the surface of their leaves (also called stomata), which release salt.
- exclusion—the membranes in the root system of some mangroves filter the sea water, allowing water to pass into the plant, but excluding most of the salt. (ROOT SYSTEMS HAVE STRUCTURES TO EXCLUDE THE SALT)
SEEDS:
- VIVIPAROUS: This means 'live birth'. The seeds are still attached to the parent tree to increase the chance of survival.
- PERICARP: a 'seed coat' that is thick and hairy, which traps the air and makes the seed 'buoyant'
- FAST ROOT GROWTH: a 'tap' or 'anchor' root grows in only 2 weeks. The seedling survives for two years and develops or dies.
LEAVES:
- WAXY CUTICLE: the waxy, coated upper layer of the leaf prevents water loss and extreme exposure to the sunlight (sunburn)
- PHOTOTAXIS: the leaves can turn 'edge on' to the hot sun, reducing burning. Means 'movement by light'
- SALT ELIMINATION: 5% of salt is eliminated through holes in the leaves
- WAXY CUTICLE: the waxy, coated upper layer of the leaf prevents water loss and extreme exposure to the sunlight (sunburn)
- PHOTOTAXIS: the leaves can turn 'edge on' to the hot sun, reducing burning. Means 'movement by light'
- SALT ELIMINATION: 5% of salt is eliminated through holes in the leaves
ROOT SYSTEM- PNEUMATOPHORES:
- PNEUMATOPHORE: acts like a snorkel channelling air to the respiring root cells.
- SALT EXCLUSION: 80-95% of salt is excluded whilst about 5% enters the roots
MANGROVE ANIMAL- THE SACRED IBIS:
- Lack of feathers on the neck and head of the ibis reduces water logging
---> as well as featherless legs for wading in shallow waters
- Long curved beak (can be 24 cm) for probing into mud for food
- Long Toes to spread body weight over the mud