1. Chapter 7
Multicellular Primary Producers

2. Seaweeds
Seaweeds!!!
Come in all kinds of interesting
Shapes and sizes!
• some are delicious!
• some are poisonous
• Some have weird names
• Come in all sorts of colors

3. Seaweed Structure
• Thallus-body
• Lack vascular tissue -Do not
have roots, stems, or leaves
• Holdfast -The structure
that attaches the seaweed
to the substrate
• Stipe-stem-likestructure

4. Phylum Chlorophyta (green algae)
• Contain chlorophylls a and b for photosynthesis
• Most are freshwater
• Ecologically important
– food source
– Contribute to coral reef formation
– Some are invasive

5. Green algae structure
• Most unicellular
• Marine species have coenocytic thallus-
containing more than 1 nucleus
– Occurs by cell growing
– nucleus divides
but cell never
divides

6. Reproduction of Algae
• Sexual
• Gametes released from gametophyte 2 flagella
• spores released from sporophyte- 4 flagella

7. Representative species
• Halimeda
• Caluerpa-invasive

8. CFU: Green Algae
• Are green algae unicellular or multicellular
• Autotrophic or heterotrophic
• What is an important organelle in
photosynthesis
• How does green algae grow in length?
– Same cell, division of nucleus
• What is the function of the Stipe?

9. Red Algae

10. Phylum Rhodophyta (red algae)
• Primarily marine
• Most diverse among seaweeds
• Cholorphylls a and d, pigments:
phycoerythrins and phycocyanins
• Not always red in color- can appear yellow to
black

11. Structure
• Multicellular and less than 1 meter long
• Wide variety of shapes and organization
among species

12. Reproduction
• Can vary from simple
to complex…but 2
unique features………..
1. Lack flagella on
spores and gametes
2. 3 multicellular stages
1. Carpospore-unique
to red
algae

13. Ecological Roles
• Porphhra- used as food in oriental dishes
• Seasonal food source for
urchins, mollusks, fish, and crustaceans
• Some grow on other plants or animals
• Help form base of coral reef
• Agar- used as a thickening agent in foods such
as ice cream, pudding, and salad dressings
• Used in cosmetics for creamy foundations

14. CFU: Red Algae
• Heterotrophic or Autotrophic?
• Multicellular or unicellular
• What are the two unique stages?
• What organisms feed on red algae?

15. Brown Algae

16. Phaeophyta (brown algae)
• Mostly marine
• Higher diversity than green but less diverse
than red
• Size: from microscopic to kelps (100 meters)
• Chlorophylls a and c and pigment fucoxanthin
• Mostly in high latitudes
• Large flat leaf-like blades with bladders help
bouy plant toward light
• Representative species Sargassum, Fucus

17. reproduction
• Gametophyte is
eliminated from
life cycle (difference
from Chlorophyta and
Rhodophyta)
• Egg develops
root-like
structures
(rhizoids) after
fertilization

18. Ecological role
• Habitats for a variety of marine life
• Harvested for thickening agents used in
dentistry, cosmetic, and food industries
• Previously iodine was extracted and put into
table salt (iodized salt) to prevent a goiter

19. • Excessive nutrients
– Runoff from fertilizer Human Impacts
• Causes huge algae
blooms!
– When algae dies off
decomposers consume
majority of the oxygen in
the environment
– Eutrophication
• Kills off fish and marine
life

20. CFU: Algae
• What macromolecule allows algae to live in
marine environments without swelling?
• What causes algae blooms?
• What is this process called?
• What are the harmful effects of algae blooms?

21. Sea grasses, salt marsh plants,
mangroves

22. Salt Marsh Plants and Sea Grasses
• Salt marshes are in Estuaries
– The kidneys of the coasts
• Nursery for small fish
– 75% of commercial fish are hatched in estuaries
• Estuaries are severly affected by humans
– Coastal development
– Pollution
– Eutrophication
• Protect us from storms

23. Phylum Anthophyta
• Seagrasses, salt marsh plants, mangroves
• Ecological Roles- Primary
producers, habitats, stabilizing sediments
• Help slow down erosion
• Have to deal with extreme changes in salinty
and oxygen
Mixing of salt and fresh water
Eutrophication

24. Sea grasses (marine flowering plants)
• Related to lilies
• Reproduce by pollination of seed; Male and female flowers on
separate plants contain pollen
• Literally look like grass
• Food for manatees and sea turtles
• Can live up to 100 meters below sea level

25. Sea Grasses in Florida
• 12 genra
– Genra native to Florida
• Syringodium -
manateegrass
• Halophila-paddlegrass
• Thalassia- turtlegrass
• Ruppia-
• Halodule- shoalgrass

26. Salt Marsh Plants
• Adapted to high levels of salinity and tidal action
• Found in estuaries – level of succession based on salinity and tidal
tolerance
• Species native to Jacksonville
– SpartinaAlternaflora
– BatisMaritima
– Spartina patens
– Juncus
– Salicorniavirginica

27. Mangroves
• Found in south of St. Augustine to Key West
• 3 genra local to Florida
– Rhizophora mangle –red mangle-----prop roots
– Avicennia germinans – black mangle---
pneumatophores
– Laguncularia racemosa- white mangle
• Distinctive by their root system and pods

28. Mangroves: Highly adaptive
• Use active transport to
regulate water levels in
their roots
• Live in anaerobic mud
– Why they stand above
the water
• Protect coral reefs from
eutrophication
– Filter, kidney

29. Help Protect Coastal Development
2004 Indian Ocean
Tsunami

30. Mangrove reproduction
• Flowers pollinated by wind or bees
• Embryo grows on the plant in a propagule
(similar to seed)
• Propagule eventually falls from parent and is
carried by current until it settles and takes
root

31. Red Mangrove
Black Mangrove
Red, White, and Black mangrove White Mangrove
leaves