Chapter 7

Multicellular Primary Producers

• 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??

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

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

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=aT4LY2KcOrs

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

Reproduction (draw pic in your reproductive box)

• Sexual • Gametes released from gametophyte 2 flagella• spores released from sporophyte-4 flagella

Representative species

• Halimeda• Mermans shaving brush

Phylum Rhodophyta (Red algae)

• Primarily marine• Most diverse among seaweeds• Not always red in color- can appear yellow to

black

Structure• Multicellular and less than 1 meter long• Wide variety of shapes and organization

among species• Chlorophylls a and d, pigments:

phycoerythrins and phycocyanins

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. Tetrasporophyte3. Cystocarp

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

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

Reproduction

• Gametophyte is eliminated from life cycle (difference from Chlorophyta and

Rhodophyta)• Egg develops

root-like structures (rhizoids) after fertilization

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

Phylum Anthophyta

• Seagrasses, salt marsh plants, mangroves• Ecological Roles- Primary producers, habitats,

stabilizing sediments

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

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

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

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

Black Mangrove

Red Mangrove

Red, White, and Black mangrove leaves

White Mangrove