Multicellular Primary Producers Seaweeds and Plants

1. Multicellular Primary ProducersSeaweeds and Plants Chapter 6

2. All photosynthetic? Most are photosynthetic but of course there are exceptions Some are not photosynthetic and are actually parasites of other seaweeds!

3. The role of seaweeds • Transform solar every to chemical energy in the form of organic matter • Energy is then available for consumption • Habitat • Oxygen producers

4. Structure of seaweeds • Seaweeds are eukaryotic • Seaweeds still lack the specialized structures and reproductive mechanisms characteristic of terrestrial plants • Wide range of variation among seaweeds

5. Variation • Rocky shore- small and sturdy to withstand waves • Some delicate ones live on other seaweeds • Kelps- found offshore in cold waters (giants)

6. General Structure • Seaweeds lack true leaves, stems, and roots of plants. • Thallus- Complete body • Blades- Leaf-like flattened portions of the thallus, large surface area, photosynthesis • Pneumatocysts- Gas-filled bladders that can keep blades close to sea surface • Stipe- Stem-like structure for support, blades originate • Holdfast- Attaches the thallus to the bottom and well developed in kelps

7. Structure

8. Types of Seaweeds • Three types • 1) Green • 2) Brown • 3) Red

9. Green Algae • Most are freshwater and terrestrial • 10% of the 7,000 species are marine • Most have a simple thallus compared to the other 2 groups • Thought that land plants evolved from green algae • Pigments and food reserve are the same

10. Where do green algae live? • Common on rocks in shallow water • Rocky shore tide pools

11. Types of green seaweeds • Filamentous types may be branched or unbranched • Enteromorpha- thin thallus in the form of a hollow tube • Ulva- Sea lettuce is paper thin • Valonia- forms large spheres or curious spherical clusters. • Caulerpa- Single giant cell with many nuclei • Codium- Deadman’s fingers • Halimeda- Calcareous green algae (coral reefs)

12. Enteromorpha

13. Ulva

14. Valonia

15. Caulerpa

16. Codium

17. Halimeda

18. Brown Algae • Coloration – varies from olive green to dark brown • Fucoxanthin over chlorophyll • Almost all of the 1500 species are marine • Often the dominant primary producers on temperate and polar rocky coasts. • Largest and structurally most complex (Include the kelps)

19. Types of Brown Algae • Ectocarpus- Finely filamentous thallus • Dictyota – thallus is flat and branched • Padina- Fan-shaped and lightly calcified • Desmaretia- branched • Some are exposed at low tides at the middle and upper levels of rocky shores • Gas-filled floats – rockweeds or wracks

20. Sargassum • Brown algae found in warm waters (Gulfs of Mexico and California) • Sargasso weed has spherical air bladders to keep small leaf like blades afloat • Most grow on rocks • Offshore in huge masses • Sargasso Sea • Area in Atlantic

21. Sargasso Sea

22. Sargassum Sea • http://www.youtube.com/watch?v=JFxhlyJ3U4Q

23. Kelps • Most complex and largest of all brown algae • Great importance – provide food and shelter for many organisms. • Laminaria- species of kelp where a single large blade can be up to 10 ft • Agarum and Alaria – Rib runs along the middle of a single blade • Egregia- Feather boa kelp • Eisenia- Southern sea palm • Nereocystis- Bull kelp • Pelagophycus- Antler like branches

24. Brown Algaes Padina • kelp.gifkelp.gif Agarum Egregia Dictyota Ectocarpus Laninaria Desmarestia Alaria Nereocystis Eisnia Pelagophycus

25. Macrocystis • Largest of kelps • Massive holdfast attaches to the bottom • At the base of each blade a gas-filled pneumatocyst • Can grow 20 in per day in optimal conditions • Form kelp beds or forests • Among the richest, most productive environments in the marine world

26. Kelp Forest • http://www.youtube.com/watch?v=GcbU4bfkDA4 • What coast of North America can they be found? • What do kelps consist of? • What do young kelp compete for? • What do fish use the kelp forest for? • Why does the canopy make a good nursery environment?

27. Red Algae • More red algae that green and brown combined • Red pigments known as phycobilins • Essentially marine • Of the 4000 species, only a few are fresh water or soil • Live in most shallow-water marine environments

28. Structure of Reds • Simplified in structure by becoming parasites of other seaweeds • A few have lost all chlorophyll and are heterotophs • Most are filamentous • Thickness, width, arrangement of filaments varies

29. Types of Reds • Gelidium • Gracilaria • Endocladia –wirey clumps on rocky shores from Alaska to S. Ca. • Gigartina- Most massive of the red algae • Porphyra-Common on rocky shores above the lowest tide mark • Rhodymenia –Common in North Atlantic • Chondrus –Irish moss and can tolerate wide ranges in temp, light and salinity

30. Red Algae Gelidium Gracilaria • en Porphyra Rhodymenia Endocladia Gigartina Chondrus

31. Coralline Algae (Corallina) • Red algae that deposit calcium carbonate in their cell walls • Important in several marine environments • Calcified thallus takes a variety of shapes • Color varies from light to intense reddish-pink • Warm-water coralline algae are actively involved in formation and development of coral reefs

32. Bingo • Thallus • Blades • Pneumatocysts • Stipe • Holdfast • Green algae • Red algae • Brown algae • Enteromorpha • Ulva • Valonia • Caulerpa • Halimeda • Gigartina • Chondrus • Fucoxanthin • Ectocarpus • Dictyota • Padina • Desmarestia • Rockweeds • Sargasso Sea • Laminaria • Nereocystis • Pelagophycus • Macrocystis • Kelp forest • Phycobilins • Coralline algae • Gracilaria • Porphyra