Higher Plants
• Coastal zone incl intertidal: mangroves/salt marshes; seagrass vegetations: prevention of substrate removal, filtration of water, provision of habitat for animals.
Higher Plants
• Coastal zone incl intertidal: mangroves/salt marshes; seagrass vegetations: prevention of substrate removal, filtration of water, provision of habitat for animals.
• Not many 'true marine plants' (seagrasses); others 'surviving in marine environment‘.
Mangroves• Tropics! Optimal: evergreen forests; ecological stress (temperature,
salinity): shrubs.
At land-sea interface, salt tolerant forested wetlands.
Mangroves• Tropics! Optimal: evergreen forests; ecological stress (temperature,
salinity): shrubs.At land-sea interface, salt tolerant forested wetlands
• Requirements:
- tropical temps,
- fine-grained alluvium,
- no strong wave or tidal actions,
- salt water (><),
- large tidal range.
Mangroves• Tropics! Optimal: evergreen forests; ecological stress (temperature,
salinity): shrubs.At land-sea interface, salt tolerant forested wetlands.
• Requirements: tropical temps, fine-grained alluvium, no strong wave or tidal actions, salt water (><), large tidal range.
• Species-rich: SE-Asia >< species-poor: Africa, America.
Mangroves• Tropics! Optimal: evergreen forests; ecological stress (temperature,
salinity): shrubs.At land-sea interface, salt tolerant forested wetlands.
• Requirements: tropical temps, fine-grained alluvium, no strong wave or tidal actions, salt water (><), large tidal range.
• Species-rich: SE-Asia >< species-poor: Africa, America.
• Adaptations to environment:
Mangroves
Adaptations to environment:• Water stress: freshwater plants! energy in inverse
osmosis: slow growth, sensitive to extra stress (pollution).
Mangroves• Adaptations to environment• Water stress: freshwater plants! energy in inverse osmosis: slow
growth, sensitive to extra stress (pollution).
Adaptations:
- fleshy leaves,
Sonneratia alba: detail of a flower (stamens grouped in separate
packages); remark the fleshy leaves.
Mangroves• Adaptations to environment• Water stress: freshwater plants! energy in inverse osmosis: slow
growth, sensitive to extra stress (pollution).
Adaptations:
- fleshy leaves,
- thick cuticle + waxy layer,
Mangroves• Adaptations to environment• Water stress: freshwater plants! energy in inverse osmosis: slow
growth, sensitive to extra stress (pollution).
Adaptations:
- fleshy leaves,
- thick cuticle + waxy layer,
- stomata on lower leaf surface & sunken;
Left: fleshy leaf with thick cuticle, thick waxy layer, sunken stomata on lower leaf surface.Right: thin leaf with thick cuticle, peltate hairs and sunken stomata on lower leaf surface.
thick wax layercuticle
fleshy leaf
cuticlethick waxy layer
sunken stomate
peltate hairscuticle
thin, “dry” leaf
cuticlepeltate hairs
sunken stomate
Mangroves• Adaptations to environment• Water stress: freshwater plants! energy in inverse osmosis: slow
growth, sensitive to extra stress (pollution).
Adaptations:
- fleshy leaves,
- thick cuticle + waxy layer,
- stomata on lower leaf surface & sunken;
- thin leaves: peltate hairs.
Conocarpus (buttonwood) with thin, silvery leaves due to the hairy
surface (limitation of evaporation). (Bahamas).
Mangroves• Adaptations to environment• Water stress: freshwater plants! energy in inverse osmosis: slow
growth, sensitive to extra stress (pollution).
Adaptations:
- fleshy leaves,
- thick cuticle + waxy layer,
- stomata on lower leaf surface & sunken;
- thin leaves: peltate hairs.
- + drop roots: absorbing rainwater.
Mangroves• Adaptations to environment
- Water stress: freshwater plants! energy in inverse osmosis: slow growth, sensitive to extra stress (pollution)
- Anoxic environment: soil water-saturated -> respiratory roots:
Mangroves• Adaptations to environment
- Water stress: freshwater plants! energy in inverse osmosis: slow growth, sensitive to extra stress (pollution)
- Anoxic environment: soil water-saturated -> respiratory roots:
1. Rhizophores + lenticels + aerenchyma.
Lenticle of an Avicennia-pneumatophore on transverse section: the outer cork tissue (c) is torn apart due to increased cell division of cambial and phelloderm cells: gas exchange is hereby made possible but (salt) water cannot intrude (scale bar = 300 µm).
Transverse section through a pneumatophore of Avicennia: the outer periderm (p) = cork cells, cortex (c) = threedimensional network of cells and air spaces, surrounding the central stele (s = vascular system) (scale bar = 300 µm).
Mangroves• Adaptations to environment
- Water stress: freshwater plants! energy in inverse osmosis: slow growth, sensitive to extra stress (pollution)
- Anoxic environment: soil water-saturated -> respiratory roots:
1. Rhizophores + lenticels + aerenchyma
2. Pneumatophores on cable roots + +
Avicennia: radiating cable roots under the sand surface, bearing the negative
geotropic pneumatophores (pencil roots).
Avicennia: at high tide the tips of the pneumatophores (provided with
lenticles) remain above water.
Mangroves• Adaptations to environment
- Water stress: freshwater plants! energy in inverse osmosis: slow growth, sensitive to extra stress (pollution)
- Anoxic environment: soil water-saturated -> respiratory roots:
1. Rhizophores + lenticels + aerenchyma
2. Pneumatophores on cable roots + +
3. Knee roots + +
Mangroves• Adaptations to environment
- Water stress: freshwater plants! energy in inverse osmosis: slow growth, sensitive to extra stress (pollution)
- Anoxic environment: soil water-saturated -> respiratory roots:
1. Rhizophores + lenticels + aerenchyma
2. Pneumatophores on cable roots + +
3. Knee roots + +
4. Buttress roots + +
Mangroves• Adaptations to environment
- Water stress: freshwater plants! energy in inverse osmosis: slow growth, sensitive to extra stress (pollution)
- Anoxic environment: soil water-saturated -> respiratory roots:
1. Rhizophores + lenticels + aerenchyma
2. Pneumatophores on cable roots + +
3. Knee roots + +
4. Buttress roots + +
+ epiphytic macroalgae.
Sonneratia alba: healthy, raher shaded pneumatophores with thick cushions of mainly red algal epiphytes.
Plunging view on the epiphytic algae: they don’t exclusively cover the pneumatopho-res, but they also spread on the sandy substrate!
Mangroves• Adaptations to environment
- Water stress: freshwater plants! energy in inverse osmosis: slow growth, sensitive to extra stress (pollution)
- Anoxic environment: soil water-saturated -> respiratory roots: rhizophores + lenticels + aerenchyma, pneumatophores on cable roots + +,
knee roots + +, buttress roots + +, + epiphytic macroalgae.
- Muddy substrate/tidal effect: vivipary (propagules)
Bruguiera gymnorhiza: flowers; in the upper flower the corolla and stamens are gone, the calyx and pistil are visible.
Rhizophora: flowers of the new season and propagules of the previous season (the pale part is the stem growing while still attached in the fruit).
Mangroves
• Associated fauna: crabs!! Snails.
• Niche diversity!! Canopy; lower part of stems and aerial roots; muddy substrate around roots >< between trees.
Mangroves
• Associated fauna: crabs!! Snails.
• Niche diversity!! Canopy; lower part of stems and aerial roots; muddy substrate around roots >< between trees.
• Ecological roles of mangroves• - soil formation by trapping debris (aerial roots!! + filamentous algae);
• - filter land run-off -> removing terrestrial organic matter;
The intricate rootsystems are excellent sediment traps and serve as
refugia for organisms against their predators.
Mangroves
• Associated fauna: crabs!! Snails.
• Niche diversity!! Canopy; lower part of stems and aerial roots; muddy substrate around roots >< between trees.
• Ecological roles of mangroves- soil formation by trapping debris (aerial roots!! + filamentous algae);
- filter land run-off -> removing terrestrial organic matter;
- habitats for many faunal species (nursery function!)
Mangroves
• Associated fauna: crabs!! Snails.
• Niche diversity!! Canopy; lower part of stems and aerial roots; muddy substrate around roots >< between trees.
• Ecological roles of mangroves- soil formation by trapping debris (aerial roots!! + filamentous algae);
- filter land run-off -> removing terrestrial organic matter;
- habitats for many faunal species (nursery function!);
- producers of detritus -> offshore productivity.
But in some seasons large quantities of seagrass leaves and seaweeds (Sargassum) are transported into the mangroves and deposited between the root systems.
Mangroves
• Associated fauna: crabs!! Snails.
• Niche diversity!! Canopy; lower part of stems and aerial roots; muddy substrate around roots >< between trees.
• Ecological roles of mangroves
- soil formation by trapping debris (aerial roots!! + filamentous algae);
- filter land run-off -> removing terrestrial organic matter;
- habitats for many faunal species (nursery function!);
- producers of detritus -> offshore productivity.
• Mangrove loss: soil reclamation for aquaculture (shrimps), agriculture, urban development (incl harbours), clear-felling, waste dumping, ...
Heavily cut mangrove. Today the whole mangrove (of which part of it is
still visible in the background on this picture) has ‘disappeared’.
Mangroves
• Associated fauna: crabs!! Snails.
• Niche diversity!! Canopy; lower part of stems and aerial roots; muddy substrate around roots >< between trees.
• Ecological roles of mangroves
- soil formation by trapping debris (aerial roots!! + filamentous algae);
- filter land run-off -> removing terrestrial organic matter;
- habitats for many faunal species (nursery function!);
- producers of detritus -> offshore productivity.
• Mangrove loss: soil reclamation for aquaculture (shrimps), agriculture, urban development (incl harbours), clear-felling, waste dumping, ...
Upstream pollution (pesticides) and eutrophication!
Mangroves
•Actual situation of mangrove vegetations worldwide: DESASTROUS!!1991: the SE Asian coastlines have lost large mangrove areas: 80% in the Philippines, 50% in Thailand and Indonesia, and 32% in Malaysia. Pression going on as greater demands are placed on forest and fishery resources along with land use-changes along coastines and in upland watersheds.
Restoration projects.
Optimal development of salt marshes restricted to the zones north and south of the 20°C-belt. (S = summer; W = winter).
General view of mud flats (with algae) and salt marshes (with higher plants) at Térénez (Morlaix, Brittany, France).
SALT MARSHES• Replacing mangroves in temperate regions.
• Shrubs, grasses, herbs: HALOTOLERANT.
• Important nursery grounds; important for wading birds.
SALT MARSHES• Replacing mangroves in temperate regions.
• Shrubs, grasses, herbs: HALOTOLERANT.
• Important nursery grounds; important for wading birds.
• Requirements for development: similar to mangroves [fine-grained alluvium, no strong wave or tidal actions, salt water (><),
large tidal range] but at least some freezing temperatures occurring.
SALT MARSHES• Replacing mangroves in temperate regions.
• Shrubs, grasses, herbs: HALOTOLERANT.
• Important nursery grounds; important for wading birds.
• Requirements for development: similar to mangroves but at least some freezing temperatures occurring.
• Adaptations to the environment: similar to mangroves: Water stress: freshwater plants! energy in inverse osmosis: slow growth, adaptation of leaves: fleshy/thin, vegetation sensitive to extra stress (pollution). Anoxic environment: soil water-saturated -> presence of aerenchyma in the plant.
SALT MARSHES• Replacing mangroves in temperate regions.
• Shrubs, grasses, herbs: HALOTOLERANT.
• Important nursery grounds; important for wading birds.
• Requirements for development: similar to mangroves but at least some freezing temperatures occurring.
• Adaptations to the environment: similar to mangroves.
• Zonation ≠ succession.
Fixation of the silt of the mud flats by diatoms (under) and filamentous + tubular green algae (up).
Common Saltmarsh-grass (Puccinellia maritima: red arrows) along the salt marsh cup, followed higher up by Sea-purslane (Halimione portulacoides: grey
coloured: yellow arrows).
Typical view of a salt marsh with a tidal gully (here almost fresh water) with the brown alga Fucus ceranoides (brown arrow) the green alga Ulva intestinalis (green
arrows), colonizing Salicornia (blue arrow) and Sea-purslane along the higher banks (yellow arrow); Térénez.
SALT MARSHES• Replacing mangroves in temperate regions.
• Shrubs, grasses, herbs: HALOTOLERANT.
• Important nursery grounds; important for wading birds.
• Requirements for development: similar to mangroves but at least some freezing temperatures occurring.
• Adaptations to the environment: similar to mangroves.
• Zonation ≠ succession.
• Ecological roles: similar to mangroves:
- production (>< uptake) of organic matter;
SALT MARSHES• Replacing mangroves in temperate regions.
• Shrubs, grasses, herbs: HALOTOLERANT.
• Important nursery grounds; important for wading birds.
• Requirements for development: similar to mangroves but at least some freezing temperatures occurring.
• Adaptations to the environment: similar to mangroves.
• Zonation ≠ succession.
• Ecological roles: similar to mangroves:- production (>< uptake) of organic matter;
- habitat (nursery) for numerous animals;
SALT MARSHES• Replacing mangroves in temperate regions.
• Shrubs, grasses, herbs: HALOTOLERANT.
• Important nursery grounds; important for wading birds.
• Requirements for development: similar to mangroves but at least some freezing temperatures occurring.
• Adaptations to the environment: similar to mangroves.
• Zonation ≠ succession.
• Ecological roles: similar to mangroves:- production (>< uptake) of organic matter;
- habitat (nursery) for numerous animals;
- stabilization of coastal substratum (root system!!);
SALT MARSHES• Replacing mangroves in temperate regions.
• Shrubs, grasses, herbs: HALOTOLERANT.
• Important nursery grounds; important for wading birds.
• Requirements for development: similar to mangroves but at least some freezing temperatures occurring.
• Adaptations to the environment: similar to mangroves.
• Zonation ≠ succession.
• Ecological roles: similar to mangroves:- production (>< uptake) of organic matter;
- habitat (nursery) for numerous animals;
- stabilization of coastal substratum (root system!!);
- filtration of coastal run off.
SEAGRASS COMMUNITIES
• MARINE (!) flowering plants; NOT grasses!!
• Mainly in tropics, forming extensive meadows, but some species also in colder regions.
SEAGRASS COMMUNITIES
• MARINE (!) flowering plants; NOT grasses!!
• Mainly in tropics, forming extensive meadows, but some species also in colder regions.
• Requirements for development:
- Salt or brackish water (estuaries); absent in freshwater!!
- submerged (at least part of the day);
- loose substrate;
- best developed on shallow slopes; limited wave action.
SEAGRASS COMMUNITIES
• MARINE (!) flowering plants; NOT grasses!!
• Mainly in tropics, forming extensive meadows, but some species also in colder regions.
• Requirements for development: salt or brackish water (estuaries); absent in freshwater; submerged (at least part of the day); loose substrate; best developed on shallow slopes; limited wave action.
• Species diversity: 58 spp worldwide; vicariance --> sister species.
SEAGRASS COMMUNITIES
• MARINE (!) flowering plants; NOT grasses!!
• Mainly in tropics, forming extensive meadows, but some species also in colder regions.
• Requirements for development: salt or brackish water (estuaries); absent in freshwater; submerged (at least part of the day); loose substrate; best developed on shallow slopes; limited wave action.
• Species diversity: 58 spp worldwide; vicariance -> sister species.
• Adaptations to environment:
- Adapted to saline environment (physiology!);
SEAGRASS COMMUNITIES
• MARINE (!) flowering plants; NOT grasses!!
• Mainly in tropics, forming extensive meadows, but some species also in colder regions.
• Requirements for development: salt or brackish water (estuaries); absent in freshwater; submerged (at least part of the day); loose substrate; best developed on shallow slopes; limited wave action.
• Species diversity: 58 spp worldwide; vicariance -> sister species.
• Adaptations to environment:- Adapted to saline environment (physiology!);
- Growing under submerged conditions: presence of aerenchyma; vascular bundles limited; thin cuticle, epidermal cells with chloroplasts; stomates absent;
Transverse section through a leaf of wheat: cuticle present, stomata present, no plasts in the epidermis, well developed vascular bundles (vb), no aerenchyma.
Transverse section through a leaf of Halodule wrightii: no cuticle, no stomata, presence of plasts in the epidermis, limited vascular bundles, presence of aerenchyma.
SEAGRASS COMMUNITIES
• MARINE (!) flowering plants; NOT grasses!!
• Mainly in tropics, forming extensive meadows, but some species also in colder regions.
• Requirements for development: salt or brackish water (estuaries); absent in freshwater; submerged (at least part of the day); loose substrate; best developed on shallow slopes; limited wave action.
• Species diversity: 58 spp worldwide; vicariance -> sister species.
• Adaptations to environment:- Adapted to saline environment (physiology!);
- Growing under submerged conditions: presence of aerenchyma; vascular bundles limited; thin cuticle, epidermal cells with chloroplasts; stomates absent;
- Withstanding wave action and tidal currents: extensive rhizomes and fleshy roots; supple leaves;
SEAGRASS COMMUNITIESMARINE (!) flowering plants; NOT grasses!!
• Mainly in tropics, forming extensive meadows, but some species also in colder regions.
• Requirements for development: salt or brackish water (estuaries); absent in freshwater; submerged (at least part of the day); loose substrate; best developed on shallow slopes; limited wave action.
• Species diversity: 58 spp worldwide; vicariance -> sister species.
• Adaptations to environment:
- Adapted to saline environment (physiology!);
- Growing under submerged conditions: presence of aerenchyma; vascular bundles limited; thin cuticle, epidermal cells with chloroplasts; stomates absent;
- Withstanding wave action and tidal currents: extensive rhizomes and fleshy roots; supple leaves;
- Carrying out hydrophilous pollination: pollen in gelatinous strands.
Massive development of diatoms on the sand; by their production of slime, sand grains ± stick together.
Massive development of diatoms on the sand; by their production of slime, sand grains ± stick together: detail.
SEAGRASS COMMUNITIES
Succession & zonationUnicellular algae (diatoms)
-> filamentous algae
-> colonizing seagrass species (long internodes)
SEAGRASS COMMUNITIES
Succession & zonationUnicellular algae (diatoms)
-> filamentous algae
-> colonizing seagrass species (long internodes)
-> succession
SEAGRASS COMMUNITIES
Succession & zonationUnicellular algae (diatoms)
-> filamentous algae
-> colonizing seagrass species (long internodes)
-> succession
-> climax vegetation
SEAGRASS COMMUNITIES
Niches with associated fauna- on and around the leaves
- on and around the stipes
SEAGRASS COMMUNITIES
Niches with associated fauna- on and around the leaves
- on and around the stipes
- around the rhizomes
SEAGRASS COMMUNITIES
Niches with associated fauna- on and around the leaves
- on and around the stipes
- around the rhizomes
- banks of dead seagrass leaves washed ashore.
Subtidal fringe: detail of Syringodium isoetifolium with cylindrical leaves; remark the sediments being deposited between the leaves!
SEAGRASS COMMUNITIES
Ecological roles- sediment trapping
- primary producers (incl epiphytic algae!)
SEAGRASS COMMUNITIES
Ecological roles- sediment trapping
- primary producers (incl epiphytic algae!)
- direct food source herbivorous fish, sea-turtles, dugongs
SEAGRASS COMMUNITIES
Ecological roles- sediment trapping
- primary producers (incl epiphytic algae!)
- direct food source herbivorous fish, sea-turtles, dugongs
- important habitats for animals (nursery!)
SEAGRASS COMMUNITIES
Ecological roles- sediment trapping
- primary producers (incl epiphytic algae!)
- direct food source herbivorous fish, sea-turtles, dugongs
- important habitats for animals (nursery!)
- important substrate for attachment (epiphytes!)
Epiphytism: the brown alga Dictyota (brownish green) and Corallinaceae (white) epiphytic op Thalassodendron ciliatum in a mangrove tide channel; the brownish colour of the water is the result of seepage from the mangrove.
SEAGRASS COMMUNITIES
Ecological roles- sediment trapping
- primary producers (incl epiphytic algae!)
- direct food source herbivorous fish, sea-turtles, dugongs
- important habitats for animals (nursery!)
- important substrate for attachment (epiphytes!)
- nutrient stripping.
Human uses and impacts- filter system for sewage effluents
- paper production
- direct food/fodder
SEAGRASS COMMUNITIES
Human uses and impacts- filter system for sewage effluents
- paper production
- direct food/fodder
- stabilizing sediments
SEAGRASS COMMUNITIES
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