Multicellular Primary Producers: Seaweeds and Plants

Multicellular Algae: The Seaweeds

•Macrophytes or macroalgae

•Multicellular, eukaryotic organisms

•There are 3 types of seaweeds;

• green

• brown

• red algae

General Structure of Seaweeds

•Body of seaweed (thallus)

•Leaf-like portions (blades)

o photosynthesis

o Gas-filled bladders (pneumatocysts)

•Stem-like structure that provides support (stipe)

•Attaches the thallus to the bottom (holdfast)

Fig. 6.1

Ulva or sea lettuce

•Green Algae

Division Chlorophyta

o Freshwater

o Marine

o Terrestrial

o Bright green from chlorophyll

Codium

Brown Algae

Division Phaeophyta

oYellow-brown pigment, fucoxanthin

oTemperate/polar

oRocky coast

oLargest/complex

Fucus, rockweed

Kelp

•Largest of all brown algae

•Macrocystis

o Largest of the kelp

o Grow 20in a day

•Kelp beds are rich in life, most productive

Red Algae

Division Rhodophyta

•Highest number of species

•Red pigments; phycobilins

•Parasite for other seaweed

•Porphyra, rocky shores

Coralline alga

•calcium carbonate in their cell walls.

Life History

•Reproduction

• asexual and sexual

• alternation of haploid and diploid generation

Economic Importance

•Mariculture

•Thick suspensions or gels at low concentrations (algin, carrageenan, and agar)

•Dairy products such as ice cream and cheese

•Frosting, Rx, shampoo, shaving cream, rubber products, paints, and cosmetics.

Flowering Plants

•Seagrasses

• true marine species adapted to soft-bottom coastal regions

• Members of the lily family evolved from terrestrial plants