odyssey expeditions - mangroves 1 noaa mangroves by dave cabrera

1Odyssey Expeditions - Mangroves

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MangrovesMangroves

By Dave Cabrera

2Odyssey Expeditions - Mangroves

IntroductionIntroduction

• Mangroves – Halophytic (salt tolerant) trees that live in areas predominantly saturated with salt water

• Found along coastlines between 32 degrees N and 38 degrees S.

• 16-24 families and 54-75 species (classification dependent)

• Highest diversity in Asia• New world has 12• US has 4 (species we will discuss)• 25% of Caribbean coastline• 75% of continental regions

3Odyssey Expeditions - Mangroves

Adaptations to Salt WaterAdaptations to Salt Water

• Salt pores – located on leaves, root and branches. Excess salt absorbed from soil secreted

• Salt exclusion – roots of some mangroves exclude salt

• Viviparity – seeds germinate while attached. Fully developed seedlings drop from tree.

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Adaptations to Low Oxygen in SoilAdaptations to Low Oxygen in Soil

• Prop Roots – roots exposed to air (red mangroves)

• Pneumatophors – pencil-like roots that stick up from the substrate (black mangroves)

• Lenticels – slits in the bark and roots

• Aerenchyma – air spaces that allow gas to reach underground roots

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Pneumatophors Lenticels

Prop roots Odyssey Expeditions

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Role of Mangrove EcosystemRole of Mangrove Ecosystem

• Mangroves as a Buffer– Protects coastline from wave action– Prevent erosion, and keep sediments from

reaching coral reefs– Collect and stabilize sediments

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6Odyssey Expeditions - Mangroves

Role of Mangrove EcosystemRole of Mangrove Ecosystem• It has been highly debated as to whether succession

occurs in mangroves. The evidence is inconclusive as to whether this happens and is considered hypothetical.

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Role of the Mangrove EcosystemRole of the Mangrove Ecosystem

• Mangroves as a nursery and a habitat– Detritus from leaves –

Bacteria feed off detritus– Bacteria – provide food for

planktonic organisms– Plankton – Serve as food

for larval and juvenile fish and invertebrates

– Shelter – protection from predators

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Odyssey Expeditions

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Roll of mangrove ecosystemRoll of mangrove ecosystem

• Diversity of species in mangroves– Trees – 54-75 species in 16-24 families– Poriferans – sponges grow on prop roots– Annelids – segmented worms live in mud and

among prop roots– Cnidarians – anemones occupy prop roots– Molluscs – Gastropods (periwinkles) and bivalve

(oysters) found on prop roots– Echinoderms – Sea cucumbers, sea stars– Urochordates – tunicates attach to roots– Birds – use tree tops– Fish – swim among roots– To name a few

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Odyssey Expeditions

9Odyssey Expeditions - Mangroves

Species of MangrovesSpecies of Mangroves• Red Mangrove (Rhizophora

mangle)– Location – found nearest to

water – Leaves elliptical and leathery.

Dark green on top, pale green underneath

– Prop roots – large aerial roots extend from tree into ground

– Roots submerged– Tolerant of low oxygen

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Odyssey Expeditions

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Red Mangrove DispersalRed Mangrove Dispersal

• Seedling dropped from tree

• Floats root down in water

• When it comes in contact with substrate it takes root and grows

• Can float around for over a year

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Red Mangrove DispersalRed Mangrove Dispersal

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Species of MangrovesSpecies of Mangroves

• Black Mangrove (Avicennia germinans)– Location – Shoreward of red

mangroves– Leaves – Oblong. Dark green on

top, pale grey to white underneath. Often encrusted with salt.

– Pneumatophores – Pencil-like root extensions that provide surface area for gas exchange

– Roots submerged only at high tide– Tolerant of low oxygen

NOAA

NOAA

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Species of MangrovesSpecies of Mangroves• White Mangrove (laguncularia

racemosa)– Location – Terrestrial side of

mangrove stands. Behind black mangroves.

– Leaves – Broad flattened and oval. Leaves branch out from stem opposite to each other

– Salt Pores – Present at base of leaves

– Soil fully saturated with water– Tolerant of salty soils– Less tolerant of high water

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NOAA

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Species of MangrovesSpecies of Mangroves

• Buttonwood (Conocarpus erectus)– Location – Terrestrial side of

mangrove stands, behind black mangroves. Not a true mangrove

– Leaves – Elliptical and leathery. Dark green on top, pale green underneath

– Salt Pores – Present at base of leaves

– Soil is damp, but not saturated– Tolerant of salty soils– Not tolerant of high water

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NOAA

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Threats to Mangrove EcosystemThreats to Mangrove Ecosystem

• Deforestation– Coastal development– Shrimp farming– Flooding– Charcoal and timber industry

Rice Shrimp and development

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Threats to Mangrove EcosystemThreats to Mangrove Ecosystem

• Pollution– Point source pollution – sewers, industrial

discharge, oil spills – Non-point source pollution – agriculture runoff

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Oil