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

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 Carrageenan
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 Kelp form massive undersea forests
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 Blade Holdfast Stipe The seaweed body
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