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Chapter 6 Multicellular Primary Producers: Seaweeds and Plants

Chapter 6 Multicellular Primary Producers: Seaweeds and Plants. Seaweeds. - multicellular (a few exceptions), eukaryotes -important source of food, habitat -producers of oxygen for organisms on land and in oceans -economic importance -also called MACROPHYTES or MACROALGAE

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Chapter 6 Multicellular Primary Producers: Seaweeds and Plants

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  1. Chapter 6 Multicellular Primary Producers: Seaweeds and Plants

  2. Seaweeds -multicellular (a few exceptions), eukaryotes -important source of food, habitat -producers of oxygen for organisms on land and in oceans -economic importance -also called MACROPHYTES or MACROALGAE -NOT PLANTS (Kingdom Protista) -Lack true roots, stems, leaves

  3. General Structure: -thallus: complete body -blade: leaflike flattened portion -pneumatocysts: gas-filled bladders -stipe: stem-like structure -holdfast: rootlike portion that attaches thallus to bottom

  4. General Structure

  5. Holdfast

  6. 3 Major Divisions (Phyla): -Green algae (PHYLUM CHLOROPHYTA) -Brown algae (PHYLUM PHAEOPHYTA) -Red algae (PHYLUM RHODOPHYTA)

  7. Green Algae CHLOROPHYTA

  8. Green Algae • Mostly freshwater and terrestrial environments • Also bays estuaries, rocky tide pools • Simpler thallus than red or brown algae • Pigments and food reserve (starch) same as land plants • Land plants evolved from green algae • Typically bright green (chlorophyll not masked by other pigments)

  9. Genera of Green Algae • Enteromorpha • Ulva • Valonia • Caulerpa • Codium • Halimeda

  10. Enteromorpha • Filamentous • Thin thallus in the form of a hollow tube

  11. Enteromorpha

  12. Ulva • Also called sea lettuce • Paper-thin sheets • Shape varies according to environmental factors • Polar to tropical

  13. Ulva

  14. Valonia • Large spheres or clusters of spheres • Tropical and subtropical

  15. Valonia

  16. Caulerpa • Tropical and subtropical • Great variety of shapes • Thin filaments or tubes (siphons) formed by a single giant cell with many nuclei

  17. Caulerpa

  18. Codium • “Dead man’s fingers” • Multinucleated filaments woven into a branching thallus • Tropical to temperate • Both coasts of North America

  19. Codium

  20. Halimeda • Calcareous green alga • Numerous segments with deposits of CaCO3 • Accumulation of dead, calcified segments plays an important role in the formation of coral reefs

  21. Halimeda

  22. Coral Reef Seaweeds-3 major groups • Turf algae-small, filamentous, colonize vacant surfaces that cover non-living hard surfaces on the reef • Coralline algae-red algae; produce hard calcareous skeleton; hold reefs together • Macroalgae (larger in size)-together with coralline algae plays role in CaCO3 deposition

  23. Coral Reef Seaweeds • Seaweeds not often regarded as components of healthy coral reefs • Reefs impacted by pollution are often overrun with seaweeds • Coral Reef Ecosystem Divison (CRED) of NOAA found that in central Pacific Ocean (subtropical northwestern Hawaiian islands), some healthy coral reefs are dominated by seaweeds rather than corals

  24. Brown Algae PHAEOPHYTA

  25. Brown Algae • Varies from olive green to dark brown • Contains yellow-brown pigments: FUCOXANTHIN (versus chlorophyll) • Usually temperate and rocky polar coasts • Largest & most complex seaweeds

  26. Genera of Brown Algae • Ectocarpus • Dictyota • Padina • Desmarestia • Fucus • Ascophyllum • Sargassum • Kelps (several genera: Laminaria, Agarum, Alaria, Postelsia, Egregia, Eisenia, Nereocystis, Pelagophycus, Macrocystis)

  27. Ectocarpus • Simplest brown algae • Finely filamentous thallus

  28. Ectocarpus

  29. Dictyota • Flat, branched thallus • Tropical and subtropical

  30. Dictyota

  31. Padina • Lightly calcified • Fan-shaped • Tropical and subtropical

  32. Padina

  33. Desmarestia • Typically Antarctic, some species in temperate areas

  34. Desmarestia

  35. Ascophyllum • Knotted seaweed • Temperate Atlantic coasts

  36. Ascophyllum

  37. Fucus • Rockweed, wracks • Atlantic and Pacific Coasts • North American and other temperate shores

  38. Fucus

  39. Sargassum • Warm waters, including Gulf of Mexico and CA • Sargasso Sea (in the Atlantic, north of West Indies) • Most species grow on rocks • 2 species float offshore in huge masses

  40. Sargassum

  41. Sargasso Sea

  42. Kelps Laminaria Agarum Alaria Postelsia Nereocystis Pelagophycus Macrocystis

  43. Laminaria • Single large blade, up to 3 m in length • Blades harvested for food • May have a split or branched blade

  44. Laminaria

  45. Agarum • Conspicuous rib runs along the middle of a single blade

  46. Agarum

  47. Alaria • Like Agarum, with a conspicuous rib running down the middle of a single blade • Blades can be as long as 25 m

  48. Alaria

  49. Postelsia • Known as sea palm because of its appearance • Grows on intertidal rocks with heavy wave action • Thick clusters from central California to British Columbia

  50. Postelsia

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