This document discusses the four main phyla of multicellular primary producers: seaweeds (Phaeophyta, Rhodophyta, Chlorophyta), seagrasses, salt marsh plants, and mangroves. It describes their key structures, reproduction methods, ecological roles, and representative species found in Florida. The main environmental factors that influence seaweeds are light, temperature, tidal exposure, salinity, and nutrient availability.

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