Mangroves By Dave Cabrera Odyssey Expeditions Mangroves 1

Mangroves By Dave Cabrera Odyssey Expeditions - Mangroves 1 NOAA

Introduction • 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 Odyssey Expeditions - Mangroves 2

Adaptations 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. Odyssey Expeditions - Mangroves 3

Adaptations to Low Oxygen in Soil • Prop Roots – roots exposed to air (red mangroves) • Pneumatophors – pencillike 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 Prop roots Pneumatophors Odyssey Expeditions Lenticels NOAA Odyssey Expeditions - Mangroves 4

Role 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 NOAA Odyssey Expeditions - Mangroves 5

Role 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. Odyssey Expeditions - Mangroves 6

Role 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 Odyssey Expeditions - Mangroves Odyssey Expeditions NOAA 7

Roll 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 Odyssey Expeditions - Mangroves Odyssey Expeditions NOAA 8

Species 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 Odyssey Expeditions - Mangroves NOAA Odyssey Expeditions 9

Red 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 Odyssey Expeditions - Mangroves 10

Red Mangrove Dispersal Odyssey Expeditions - Mangroves 11

Species 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 Odyssey Expeditions - Mangroves NOAA 12

Species 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 NOAA Odyssey Expeditions - Mangroves 13

Species 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 Odyssey Expeditions - Mangroves NOAA 14

Threats to Mangrove Ecosystem • Deforestation – Coastal development – Shrimp farming – Flooding – Charcoal and timber industry Rice Odyssey Expeditions - Mangroves Shrimp and development 15

Threats to Mangrove Ecosystem • Pollution – Point source pollution – sewers, industrial discharge, oil spills – Non-point source pollution – agriculture runoff Oil NOAA Odyssey Expeditions - Mangroves 16