1. Chapter 7
Multicellular Primary Producers

2. • Remember how much seaweed was in your
household products…..
– What were some of the product that contained
algae that you found in your home in Lab 2??

3. Seaweeds
• Most found attached to a substrate
• Inhibit 2% of seafloor
• Life in the inner continental shelf depend upon
seaweeds for food
• Abiotic Factors most influential are
– Light *****
– Temp***** (most diverse in tropical waters)
– Tidal exposure
– Salinity
– Availability of nutrients

4. 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-like structure

5. Phylum Chlorophyta (green algae)
• Ecologically important
– food source
– Contribute to coral reef
formation
– Some are invasive
• Caulerpa taxifolia
– https://www.youtube.c
om/watch?v=aT4LY2Kc
Ors

6. Green algae structure/characteristics
• Most unicellular
• Most are freshwater( we saw some out at
pond)
• Contain chlorophylls a and b for
photosynthesis
• Marine species have coenocytic thallus-
containing more than 1 nucleus
– Occurs by cell growing nucleus divides but cell
never divides

7. Reproduction (draw pic in your
reproductive box)
• Sexual
• Gametes released from gametophyte 2 flagella
• spores released from sporophyte-4 flagella

8. Representative species
• Halimeda
• Mermans shaving brush

9. Phylum Rhodophyta (Red algae)
• Primarily marine
• Most diverse among seaweeds
• Not always red in color- can appear yellow to
black

10. Structure
• Multicellular and less than 1 meter long
• Wide variety of shapes and organization
among species
• Chlorophylls a and d, pigments:
phycoerythrins and phycocyanins

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

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

13. 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 buoy
plant toward light
• Representative species
Sargassum, Fucus

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

15. 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

16. Phylum Anthophyta
• Seagrasses, salt marsh plants, mangroves
• Ecological Roles- Primary producers, habitats,
stabilizing sediments

17. Sea grasses (marine flowering plants)
• Related to lilies
• Reproduce by pollination of seed; Male and
female flowers on separate plants contain
pollen
• 12 genra
– Genra native to Florida
• Syringodium -manateegrass
• Halophila-paddlegrass
• Thalassia- turtlegrass
• Ruppia-
• Halodule- shoalgrass

18. 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 (will be responsible for these on the test!!!)
– Spartina Alternaflora
– Batis Maritima
– Spartina patens
– Juncus
– Salicornia virginica

19. 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

20. 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

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