1.b. Macroalgae
In freshwater biota: limited: Charophytes
• Along coastlines: on rocky substrate + in mangroves + in salt marshes + on seagrasses.
Mangrove with aerial roots (pneumatophores) densely covered by epiphytic
algae, mainly red algae (Rhodophyta).
1.b. Macroalgae
In freshwater biota: limited: Charophytes
• Along coastlines: rocky substrate + mangroves + salt marshes + seagrasses.
• Plant body = thallus: NO vascular bundles (no "true" roots, stems nor leaves although they can look like -); NO flowers; NO seeds (spores!).
Chlorophyta: Caulerpa sertularioides: structures SIMILAR to higher plants: stolonoïds, rhizoïds and feathery assimilators.
1.b. Macroalgae
In freshwater biota: limited: Charophytes
• Along coastlines: rocky substrate + mangroves + salt marshes + seagrasses.
• Plant body = thallus: NO vascular bundles (no "true" roots, stems nor leaves); NO flowers; NO seeds (spores!).
• Photosynthesis and uptake of nutrients by whole thallus.
1.b. Macroalgae
In freshwater biota: limited: Charophytes
• Along coastlines: rocky substrate + mangroves + salt marshes + seagrasses.
• Plant body = thallus: NO vascular bundles (no "true" roots, stems nor leaves); NO flowers; NO seeds (spores!).
• Photosynthesis and uptake of nutrients by whole thallus.
• Underestimated in biodiversity discussions ("invisible").
1.b. Macroalgae
In freshwater biota: limited: Charophytes
• Along coastlines: rocky substrate + mangroves + salt marshes + seagrasses.
• Plant body = thallus: NO vascular bundles (no "true" roots, stems nor leaves); NO flowers; NO seeds (spores!).
• Photosynthesis and uptake of nutrients by whole thallus.
• Underestimated in biodiversity discussions ("invisible").
• Requirements for development:
* Salt or brackish water (rare exceptions);
1.b. Macroalgae
In freshwater biota: limited: Charophytes
• Along coastlines: rocky substrate + mangroves + salt marshes + seagrasses.
• Plant body = thallus: NO vascular bundles (no "true" roots, stems nor leaves); NO flowers; NO seeds (spores!).
• Photosynthesis and uptake of nutrients by whole thallus.
• Underestimated in biodiversity discussions ("invisible").
• Requirements for development:* Salt or brackish water (rare exceptions);
* Submerged, at least part of the day;
1.b. Macroalgae
In freshwater biota: limited: Charophytes
• Along coastlines: rocky substrate + mangroves + salt marshes + seagrasses.
• Plant body = thallus: NO vascular bundles (no "true" roots, stems nor leaves); NO flowers; NO seeds (spores!).
• Photosynthesis and uptake of nutrients by whole thallus.
• Underestimated in biodiversity discussions ("invisible").
• Requirements for development:* Salt or brackish water (rare exceptions);
* Submerged, at least part of the day;
* Hard substrate: lithophytes (few exceptions: special anchorage).
1.b. Macroalgae
Species diversity: approximate numbers• Red (Rhodophyta = ± 4000-6000 spp), green
(Chlorophyta (macroalgae only!) = ± 2000 spp (+ microalgae = ~ 15000) and brown (Phaeophyta = ± 900-1500 spp) algae [and blue-greens: see micro-algae].
1.b. Macroalgae
Species diversity: approximate numbers• Red (Rhodophyta = ± 4000-6000 spp), green (Chlorophyta (macroalgae
only!) = ± 2000 spp (+ microalgae = ~ 15000) and brown (Phaeophyta = ± 900-1500 spp) algae [and blue-greens: see micro-algae].
• Some area's more species rich than others: Pacific: Philippines, Japan; Atlantic: Europe!! (N-Spain, France, UK); Caribbean!! Red Sea & Indian Ocean?? South Africa!! (different climate zones).
1.b. Macroalgae
Species diversity: approximate numbers• Red (Rhodophyta = ± 4000-6000 spp), green (Chlorophyta (macroalgae
only!) = ± 2000 spp (+ microalgae = ~ 15000) and brown (Phaeophyta = ± 900-1500 spp) algae [and blue-greens: see micro-algae].
• Some area's more species rich than others: Pacific: Philippines, Japan; Atlantic: Europe!! (N-Spain, France, UK); Caribbean!! Red Sea & Indian Ocean?? South Africa!! (different climate zones)
• Most species rich: not tropics >< terrestrial plants.
Chlorophyta (green algae)
• More closely related to higher plants than to the brown or red algae!!: photosynthesis by chlorophyll a & b, storage product = starch, cell wall component: cellulose.
Chlorophyta (green algae)
• More closely related to higher plants than to the brown or red algae!!: photosynthesis by chlorophyll a & b, storage product = starch, cell wall component: cellulose.
• Ulva (incl. Enteromorpha): bioindicators of eutrophication (+ importance of correct ID!!)
Chlorophyta: massive development of Ulva in the intertidal (Wimereux) as a result of eutrophication of the coastal
water.
Chlorophyta (green algae)
• More closely related to higher plants than to the brown or red algae!!: photosynthesis by chlorophyll a & b, storage product = starch, cell wall component: cellulose.
• Ulva (incl Enteromorpha): bioindicators of eutrophication (+).
• Codium: locally as food.
Chlorophyta (green algae)
• More closely related to higher plants than to the brown or red algae!!: photosynthesis by chlorophyll a & b, storage product = starch, cell wall component: cellulose.
• Ulva (incl Enteromorpha): bioindicators of eutrophication (+).
• Codium: locally as food.
• Halimeda: calcified -> sediments (‘Halimeda-sand’!! (atolls: up to 90%).
Chlorophyta (green algae)
• More closely related to higher plants than to the brown or red algae!!: photosynthesis by chlorophyll a & b, storage product = starch, cell wall component: cellulose.
• Ulva (incl Enteromorpha): bioindicators of eutrophication (+).
• Codium: locally as food.
• Halimeda: calcified -> sediments!! (atolls: up to 90%)
• Caulerpa: food/toxic; C. taxifolia & C. racemosa-problem in the Mediterranean Sea.
Phaeophyta (brown algae)
• Photosynthetic pigments: chlorophyll a & c + brown pigments (xanthophylls); cell wall component: alginates (see Human uses)!
Phaeophyta (brown algae)
• Photosynthetic pigments: chlorophyll a & c + brown pigments (xanthophylls); cell wall component: alginates !
• Mainly cold water (exceptions).
Phaeophyta (brown algae)
• Photosynthetic pigments: chlorophyll a & c + brown pigments (xanthophylls); cell wall component: alginates !
• Mainly cold water (exc.)
• From small and filamentous up to 65 m long; haptera (root-like) + stipe (stem-like) + lamina (blade-like) + bladders (floating).
Phaeophyta: Pylaiella littoralis: habit: branched filamentous (Wimereux): detail of a portion ~ 5 cm long.
Phaeophyta: Laminaria saccharina: haptera, stipes,
meristematic zone (arrows), basis of the blade (Wimereux).
Phaeophyta (brown algae)
• Photosynthetic pigments: chlorophyll a & c + brown pigments (xanthophylls); cell wall component: alginates !
• Mainly cold water (exc.)
• From small and filamentous up to 65 m long; haptera (root-like) + stipe (stem-like) + lamina (blade-like) + bladders (floating).
• Zonation! Adaptation to dessication, salinity and temperature fluctuations + competition.
Phaeophyta: Fucus spiralis with numerous receptacles (swollen reproductive structures) in the high intertidal.
Phaeophyta (brown algae)
• Photosynthetic pigments: chlorophyll a & c + brown pigments (xanthophylls); cell wall component: alginates !
• Mainly cold water (exc.)
• From small and filamentous up to 65 m long; haptera (root-like) + stipe (stem-like) + lamina (blade-like) + bladders (floating).
• Zonation! Adaptation to dessication, salinity and temperature fluctuations + competition.
• Dictyota & Padina frequent in tropics; also Sargassum ID-problems!! + drifting spp.
Rhodophyta (red algae)
• Photosynthetic pigments: chlorophyll a + red and blue pigments; cell wall component: carrageenans, agar, chalk (see Human Uses).
Rhodophyta (red algae)
• Photosynthetic pigments: chlorophyll a + red and blue pigments; cell wall component: carrageenans, agar, chalk!
• Mainly warm water (exceptions!).
Rhodophyta (red algae)
• Photosynthetic pigments: chlorophyll a + red and blue pigments; cell wall component: carrageenans, agar, chalk!
• Mainly warm water (exceptions!).
• From small and filamentous up to 1 m long; mostly composed of filaments sticking together by jelly.
Rhodophyta: Acrochaetium: top left: tufts of small filaments (~1 cm); other illustrations: microscopic details with spore formation.
Rhodophyta: Palmaria palmata, a tough, relatively large (~ 20 cm), blade-like red alga (Wimereux, subtidal fringe).
Rhodophyta: Batrachospermum: detail of the anatomy: filaments sticking together by jelly: central axis and
whorls of branchlets.
Rhodophyta (red algae)
• Photosynthetic pigments: chlorophyll a + red and blue pigments; cell wall component: carrageenans, agar, chalk!
• Mainly warm water (exc.)
• From small and filamentous up to 1 m long; mostly composed of filaments sticking together by jelly.
• Mostly epilithic, but numerous epiphytic species. Zonation! Mainly subtidal + intertidal pools (desiccation).
Rhodophyta: Palmaria palmata (red arrows), in situ, epilithic and the brown algae Laminaria digitata ( brown
arrow) and L. saccharina (yellow arrow) (Wimereux).
Rhodophyta: Polysiphonia lanosa, epiphytic (hemi-parasitic) on Ascophyllum nodosum (brown alga) (Wimereux): detail.
Rhodophyta (red algae)
• Photosynthetic pigments: chlorophyll a + red and blue pigments; cell wall component: carrageenans, agar, chalk!
• Mainly warm water (exc.)
• From small and filamentous up to 1 m long; mostly composed of filaments sticking together by jelly.
• Mostly epilithic, but numerous epiphytic species. Zonation! Mainly subtidal + intertidal pools (desiccation).
• Porphyra (nori): most important sea-vegetable!! Mariculture. Fundamental research (reproduction) --> applied research.
• The story of Nori and Kathleen Drew– discovery of the life cycle: Conchocelis-phase by K. Drew
• triphasic, anisomorphic cycle
• tetraspores (conchospores) grow in oyster shells
Rhodophyta (red algae)
• Photosynthetic pigments: chlorophyll a + red and blue pigments; cell wall component: carrageenans, agar, chalk!
• Mainly warm water (exc.)
• From small and filamentous up to 1 m long; mostly composed of filaments sticking together by jelly.
• Mostly epilithic, but numerous epiphytic species. Zonation! Mainly subtidal + intertidal pools (desiccation).
• Porphyra (nori): most important sea-vegetable!! Mariculture. Fundamental research (reproduction) --> applied research.
• Eucheuma (a.o.) --> carragheenophytes!! Mariculture.
Rhodophyta: mariculture of Eucheuma in Indonesia: attaching branches on the ropes; in the background: bags of dried
specimens.
Rhodophyta (red algae)
• Photosynthetic pigments: chlorophyll a + red and blue pigments; cell wall component: carrageenans, agar, chalk!
• Mainly warm water (exc.)
• From small and filamentous up to 1 m long; mostly composed of filaments sticking together by jelly.
• Mostly epilithic, but numerous epiphytic species. Zonation! Mainly subtidal + intertidal pools (desiccation).
• Porphyra (nori): most important sea-vegetable!! Mariculture. Fundamental research (reproduction) --> applied research
• Eucheuma (a.o.) --> carragheenophytes!! Mariculture.
• Gelidium: --> agar. Mariculture.
Rhodophyta (red algae)
• Photosynthetic pigments: chlorophyll a + red and blue pigments; cell wall component: carrageenans, agar, chalk!
• Mainly warm water (exc.)
• From small and filamentous up to 1 m long; mostly composed of filaments sticking together by jelly.
• Mostly epilithic, but numerous epiphytic species. Zonation! Mainly subtidal + intertidal pools (desiccation).
• Porphyra (nori): most important sea-vegetable!! Mariculture. Fundamental research (reproduction) --> applied research
• Eucheuma (a.o.) --> carragheenophytes!! Mariculture.
• Gelidium: --> agar. Mariculture.
• Corallines: "cement in coral reefs"; Med. Sea: calcified platform; coralligène; maërl (industry --> destroyed).
The seaward, surf-exposed margin of the reef, cemented by Corallinaceae,
resulting in a pinkish colour.
Rhodophyta: Corallinales. Pseudolithophyllum expansum (with epiphytic Halimeda): forming extensive structures
at great depth (>50 m), the “coralligène” (Mediterranean Sea).
Rhodophyta: Corallinales: Lithophyllum tortuosum: forming a ridge (“le trottoir”) at high tide sea level, especially at surf-
exposed sites (Mediterranean Sea).
Rhodophyta: Corallinales. Segmented representatives: left: Corallina officinalis, right: Cheilosporum sagittatum
(Australia).
Succession; zonation; niche diversity
• Bare surface -> Bacteria -> filamentous algae -> 'fleshy' seaweeds (-> seagrasses).
Succession; zonation; niche diversity
• Bare surface -> Bacteria -> filamentous algae -> 'fleshy' seaweeds (-> seagrasses).
• Conspicuous zonation (species according climate).
- Intertidal: exposure to air conditions towards high tide: desiccation, temperature & salinity variations!
- Subtidal: wave action & light (quality and quantity); down to depth with enough light for photosynthesis.
Dike at Pointe de la Crèche, Boulogne (N France): Verrucaria maura (blackish lichen), Blidingia minima (light green), Porphyra umbilicalis (brownish purple), Ulva compressa (dark green), Fucus spiralis (blackish brown), on the bottom: many Ulva.
Zonation in the Mediterranean Sea: intertidal with Rissoella verruculosa,
Lithophyllum tortuosum, Cystoseira mediterranea.
Succession; zonation; niche diversity Bare surface -> Bacteria -> filamentous algae -> 'fleshy' seaweeds (->
seagrasses).
• Conspicuous zonation (species according climate).
• Intertidal: exposure to air conditions towards high tide: desiccation, temperature & salinity variations!
• Subtidal: wave action & light (quality and quantity); down to depth with enough light for photosynthesis
• Geographic distribution: 5 marine phytogeographical zones (upper and lower boreal, temperate, subtropical and tropical) defined by critical temperatures:
- min temperature for survival;
- min temperature for repopulation;
- max temperature for repopulation;
- max temperature for survival.
Succession; zonation; niche diversity
• Bare surface -> Bacteria -> filamentous algae -> 'fleshy' seaweeds (-> seagrasses).• Conspicuous zonation (species according climate).• Intertidal: exposure to air conditions towards high tide: desiccation, temperature
& salinity variations!• Subtidal: wave action & light (quality and quantity); down to depth with enough
light for photosynthesis• Geographic distribution: 5 marine phytogeographical zones:
- min temperature for survival;
- min temperature for repopulation;
- max temperature for repopulation;
- max temperature for survival.
• Cosmopolitan species (??!! >< molecular data -> numerous sibling species). Patchiness!! Disjunct distribution.
Research along the East African coast
New recordsupdate of floristic knowledge48 species new to Kenya and Tanzania
ExampleDictyota adnata Zanardinitype locality: Irian Jaya (Indonesia) New: East Africa
Coppejans (1990)
Research Group Phycology, Ghent University
Research along the East African coast
Gibsmithia hawaiiensistype locality: Hawaiiknown from Australiënew: East Africa, South Africa
Seychellessubtidal
De Clerck et al., Bot. Mar. (subm.)
Research Group Phycology, Ghent University
New speciesVanvoorstia incipiens
intertidal
1 location: Uroa, Zanzibar
De Clerck, Wynnne & Coppejans, Phycologia (1999)
Research along the East African coast
Research Group Phycology, Ghent University
Ecological roles of the seaweed vegetations
• Defining intertidal and subtidal habitats (incl. fauna!)
Ecological roles of the seaweed vegetations
• Defining intertidal and subtidal habitats (incl. fauna!)
• Large biomass, even in mangroves and seagrass vegetations -> important role!
Ecological roles of the seaweed vegetations
• Defining intertidal and subtidal habitats (incl. fauna!)
• Large biomass, even in mangroves and seagrass vegetations -> important role!
• Consumption, phycocolloids.
Algal uses and economical potential• Uses
– food
– fertilisers
– phycocolloids
– fine biochemicals
– (fermentation and pyrolysis)
Algal uses and economical potential• Human food
– 600 BC• “Some algae are a delicacy fit for the most
honoured guests, even for the King himself”
• 21 species are used in Japan, 10% of the daily diet
– Nori = Porphyra
– Kombu = Laminaria
– Wakame = Undaria
Algal uses and economical potential• Human food
– Europe and America– health food
– traditional foods
» laver bread (Porphyra)
» cheese (Dulse: Palmaria palmatifida)
– dying agents for textiles
– pharmaceuticals (since pre-christian times: ~ officinalis)
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