1.b. Macroalgae In freshwater biota: Charophytes limited to oligotrophic, alkaline waters .

1. 1.b. Macroalgae In freshwater biota: Charophytes limited to oligotrophic, alkaline waters.

2. Charophyta: left: dense vegetation; Right: detail.

3. 1.b. Macroalgae In freshwater biota: limited: Charophytes • Along coastlines: on rocky substrate + in mangroves + in salt marshes + on seagrasses.

4. Rocky shore with extensive macroalgal (seaweed) vegetations.

5. Mangrove with aerial roots (pneumatophores)densely covered by epiphytic algae, mainly red algae (Rhodophyta).

6. Seaweed growth in a young salt marsh vegetation (Salicornia europaea).

7. Macroalgae in seagrass vegetations: the brown alga Dictyota epiphytic on Thalassodendron ciliatum.

8. 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!).

9. Chlorophyta: Caulerpa sertularioides: structures SIMILAR to higher plants: stolonoïds, rhizoïds and feathery assimilators.

10. Phaeophyta: Laminaria: structures SIMILAR to higher plants: haptera, stipe and blade.

11. Rhodophyta: Zellera tawallina with holdfast, stem-like and blade-like structures.

12. 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.

13. 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").

14. 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);

15. 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;

16. 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).

17. 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].

18. 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).

19. 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.

20. 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.

21. 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!!)

22. Chlorophyta: Ulva lactuca, Sea lettuce (Wimereux): 2-layered membrane, ~ 20 cm large.

23. Chlorophyta: Ulva (Enteromorpha) intestinalis, Intestine weed (Wimereux): 30 cm long.

24. Chlorophyta: massive development of Ulva in the intertidal (Wimereux) as a result of eutrophication of the coastal water.

25. Chlorophyta: Cladophora (Rockweed): habit and detail. Some species growing in freshwater.

26. Chlorophyta: Bryopsis spp.

27. 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.

28. Chlorophyta: Codium.

29. 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%).

30. Chlorophyta: Halimeda copiosa Calcified, segmented thallus (one segment ~ 0.5 cm).

31. Chlorophyta: Halimeda tuna (fertile, with gametangia.

32. 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.

33. Chlorophyta: Caulerpa racemosa var. racemosa: spherical assimilators.

34. Chlorophyta: Caulerpa opposita typespecimen of a new species but locally extremely abundant.

35. Phaeophyta (brown algae) • Photosynthetic pigments: chlorophyll a & c + brown pigments (xanthophylls); cell wall component: alginates (see Human uses)!

36. Phaeophyta (brown algae) • Photosynthetic pigments: chlorophyll a & c + brown pigments (xanthophylls); cell wall component: alginates ! • Mainly cold water (exceptions).

37. 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).

38. Phaeophyta: Pylaiella littoralis: habit: branched filamentous (Wimereux): detail of a portion ~ 5 cm long.

39. Phaeophyta: Laminaria saccharina, large specimen in Brittany (Roscoff): ERASMUS field-course.

40. Phaeophyta: Laminaria saccharina: haptera, stipes, meristematic zone (arrows), basis of the blade (Wimereux).

41. Phaeophyta: Laminaria saccharina: blades with double row of undulations.

42. Phaeophyta: Fucus vesiculosus, Bladder weed (Wimereux) with air vesicles (floating).

43. 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.

44. Phaeophyta: Pelvetia canaliculata-vegetation in the upper intertidal (Wimereux).

45. Phaeophyta: Fucus spiralis with numerous receptacles (swollen reproductive structures) in the high intertidal.

46. Phaeophyta: Fucus vesiculosus, in the middle intertidal (Wimereux).

47. Phaeophyta: Ascophyllum nodosum: replacing Fucus vesiculosus on sheltered places (Wimereux).

48. Phaeophyta: Fucus serratus, low intertidal (Wimereux).

49. Phaeophyta: Himanthalea elongata: zone between intertidal and subtidal (Brittany).

50. Phaeophyta: Laminaria-zone at spring low tide: Wimereux (L. saccharina, L. digitata).