Multicellular Primary Producers

1. Multicellular Primary Producers

2. Multicellular Algae • Seaweeds ( macroalgae) • Multicellular algae

3. Three groups of seaweeds • Red algae – phylum(division) Rhodophyta • Brown algae – phylum(division) Phaeophyta • Green algae – phylum(division) Chlorophyta

4. Rhodophyta

6. Irish Moss - Rich in protein and minerals

7. CorallinesSecrete a calcium carbonate shell that bond coral colonies together (holds the coral reef structure together)

8. Nori - Rich in protein and minerals

10. Phylum Rhodophyta • Red Algae • Corallines • Secrete a calcium carbonate shell that bond coral colonies together (holds the coral reef structure together) • Irish Moss • Rich in protein and minerals • Nori • Rich in protein and minerals

11. Phylum Rhodophyta • Biochemistry • Chlorophylls a, d • Phycoerythrin (red pigments) • Allow some red algae to live much deeper than any other algae • As deep as 200 m (656 ft)

12. Phylum Rhodophyta • Ecological Roles • Seasonal food for herbivores, grazers • Some form turfs and reef sediments • Some stabilize reef sediments

13. Phylum Rhodophyta • Commercial uses • Agar • Used in medicine and research for culturing microorganisms • Carrageenan • Desserts, ice cream, milk shakes, sweetened condensed milks, puddings, • sauces: gel to increase viscosity • thickener : Shampoo and cosmetic creams….

14. Red Algae – Phylum Rhodophyta • Primarily marine (98%) • The highest diversity among seaweeds • Mostly benthic in distribution • Some species are epiphytes (plant living on plant) • Coraline red algae- helps to cement loose coral together

15. Important commercial uses • Agar – culturing bacteria • Carrageenan – thickening agent • Source of food for human consumption, animal feed, and used in fertilizer

16. Phylum Phaeophyta • Brown Algae • Kelp • Sargassum • Rockweed

17. Rockweed

18. Phylum Phaeophyta • Biochemistry • Chlorophylls a, c • Pigment fucoxanthin

20. Phylum Phaeophyta • Ecological Roles • Long term food for herbivores, grazers • very productive the Giant Kelp is the foundation for many temperate coastal ecosystems: California, the Mediterranean, and New Zealand • Kelp form massive undersea forests • Habitat for diversity of marine animals • Sea urchins, fishes, crustaceans, molluscs, sea lions, sea otters

21. Phaeophyta

22. Brown Algae – Phylum Phaeophyta • Rockweeds, kelps, and sargassum • Almost exclusively marine (99.7%) • Most are benthic except for Sargassum • Range in size from microscopic to the giant kelps • Olive-brown color is due to pigment fucoxanthin (also found in diatoms)

23. Brown Algae • Blades of brown algae usually have gas-filled bladders that help them to stay afloat to get maximum exposure to sunlight • The stipe is attached to the bottom by a holdfast

25. Ecological roles of Sargassum • Sargassum forms floating mats in the North Atlantic Ocean in an area known as the Sargasso Sea • Habitat to a variety of organisms unique to the sargassum • Massive mats of sargassum support a complex and diverse community • Several species of fish and invertebrates live only in this ecosystem

29. Phylum Phaeophyta • Commercial uses • Brown algae is used as a food resource • Seaweeds and algae make up 10% of the Japanese diet • The commercial product algin is used in food processing, salad dressing, ice cream, paint, and abrasives • Food and chemical industries use about $250 million worth of algin annually

30. Commercial products from Brown Algae • The alginates of some brown algae are harvested for commercial use as thickening agents in the textile, dental, cosmetic, and food industries • Brown algae are used as food, and as cattle feed

31. Chlorophyta

32. Phylum Chlorophyta • Green Algae • Sea lettuce

33. Phylum Chlorophyta • Biochemistry • Chlorophylls a, b • Carotenoids • Chlorophyta share the same pigments as land plants • Evolutionarily significant, indicates that land plants evolved from green algae

34. Phylum Chlorophyta • Ecological Roles • Seasonal food for herbivores, grazers • Manatees eat sea lettuce • Some form turfs and reef sediments

35. Phylum Chlorophyta • Commercial uses • Can be used as a compost material and as fertilizer

36. Green Algae – Phylum Chlorophyta • Contain the same types of pigments that are found in land plants (a,b) • Few marine species (13%), most are freshwater and phytoplankton

37. Distribution of Seaweeds • Most species of seaweed are benthic • Fouling communities – live on pilings, bulkheads, boat hulls... • The environmental factors most influential in distribution • Light and temperature

38. Structure of Seaweeds • Thallus • The seaweed body • Blade • Flattened part of the thallus • Holdfast • Attaches the thallus to a surface • Stipe • Stem-like region between the holdfast and the blade

39. Photosynthetic pigments • Chloroplasts in all seaweeds have chlorophyll a • Green algae also has chlorophyll b • Brown algae chlorophyll c • Red algae chlorophyll d

40. Composition of cell walls • Primarily composed of cellulose • Calcareous algae may also have calcium carbonate

41. Reproduction in Seaweeds • Both asexual and sexual • Asexual • Fragmentation • Thallus breaks into pieces and each piece grows into a new plant • Spore formation • Sporophyte produces spores • Sexual • Gametes are produced and zygote is formed • Gametophyte produces gametes • Alternation of generations • Asexual sporophyte and sexual gametophyte in same plant