Transcript 028-Mangroves

A diverse group of trees that are salt tolerant
(halophyte) and are viviparous .
• shallow and protected tropical and subtropical
regions
• restricted to intertidal and adjacent marine
habitats
• temperature range: 10oC to 20oC
Open ocean <50 g C/m2/year
Coral reefs 1000 g C/m2/year
Mangroves 500 g C/m2/year
Continental Shelf:
Nonupwelling 200 g C/m2/year
Coastal upwelling 300 g C/m2/year
Seagrass beds 1000 g C/m2/year
Estuaries and salt marshes 800 g C/m2/year
Upwelling 300 g C/m2/year
Salt Tolerance:
What would happen if you watered your
garden with salt water?
A few mangrove species can survive in freshwater, but are
not good competitors with other species.
Mangroves have a high salt tolerance. They can survive
well in 90%o soil salinity. The ocean averages 35 %o.
They need to prevent water loss by either:
1. excrete salt at leaves
2. exclude salt at roots
3. salt excretion and abscission (remove of salt laden
organs)
Physical Factors that Effect Growth and Development:
wave action: windward (more tidal flush) vs. leeward
(get more anoxic conditions, stagnation, algae blooms)
nutrients
tidal flush
riverine flow
canopy cover
soil: low oxygen (anaerobic), high hydrogen sulfide, fine
grain soils (muddy)
anaerobic sulfur reducing bacteria
calcareous shells of mollusks are acted upon
sulfur bacteria--- in turn get Ca++ nutrients that the
mangrove and other animals need, also raises the
alkalinity of the soil.
Stresses:
1. Channelization, drainage, and siltation
2. Hurricane
3. Herbicides and defoliants
4. Pesticides and pollution
5. Thermal loading (heat)
Physiology:
Most mangrove are viviparous, they drop propagules
from branches, which are carried away by waves.
No resting seed stage: fruiting body (propagule) is a
seedling.
Prop roots help support the
tree, also the root system
can be very spread out.
Pneumatophores have a respiratory function. The
soil is very anaerobic, so the pneumatophores stick
out of the surface and take in O2. They also function
by pushing nutrients to the upper soil layer.
Ecological Role of Mangroves:
1. Stabilize sediment
2. Accumulate detrital or other foreign material
3. Habitat for epiphytes
4. Fish and invertebrate nursery
5. Nesting/roosting sites for birds
6. Limited role as a direct food source
7. Major contributor to detrital food chain
Mangrove Use:
• fish and shrimp cultivation
• natural buffers against hurricanes
• major detrital source
• nursery for many different animals
• food for: people, crabs, fungi, bacteria, other animals
• coal
• tanning material
• finest honey