Plants

The producers, Many are firmly rooted

to the bottom of the sea….

STRUCTURE

Four types of algaeUnicellularColonialFilamentousMulticellular or macrophytic

Phylum Chlorophyta –Green Algae

Algae a.k.a. seaweed

Kingdoms Protista &Chromalveolata

Chlorophyta (green algae)

Phaeophyta (brown algae)

Rhodophyta (red algae)

Eukaryotic Algae

single celled or multi-cellular, possess nuclear membrane, aquatic photoautotrophs, classified on chlorophyll, color, cell wall composition, food storage

Algal Taxonomy

Is algae in the kingdom Plantae?

A CLASSIFICATION DEBATE RAGES

MACROPHYTE ALGAE LARGE PLANTS, WHETHER AQUATIC OR MARINE…

Are red and brown algae still classified as protists?

Unicellular algae

IDENTIFY THE TYPE OF ALGAE

1. Chlorophylls a, b, c, d, e. Each molecule functions at

specific wavelengths of light. 

2. Carotenes:

carotene B- found in all three divisionsxanthophylls- 20 different types of pigments and two types:

• fucoxanthin- found only in phaeophyta• lutein- common pigment in all large algae

 

3. Phycoblins:

phycocyanin- blue pigment

phycorethrin- pink-red pigment found in

rhodophyta and cyanobacteria

Phylum Chlorophyta –Green Algae

Phylum Chlorophyta –Green Algae Pigments: Chlorophylls a and b, ß-carotene and various xanthophylls

Walls of cellulose

Food reserves: true starch, fats and oils

Eukaryotic algae: membrane-bound organelles

Flagella: 2 or 4

Phylum Chlorophyta –Green Algae Distribution and habitats

Common in ponds, ditches etc.

Attached to rocks or free floating

90% are fresh water species

Often in brackish water

Shallow, nutrient-rich water

Important marine algae in tropics

May be symbiotic, lichens (algae + fungus)

Phylum Chlorophyta – Green Algae

Caulerpa racemosa

Caulerpa sertularioides

Dictyosphaeria cavernosa

Codium eduleHalimeda opuntia

Chaetomorpha

Bryopsi

Chara

Volvox colony

Caulerpa

REPRODUCTIONMOST REPRODUCE BOTH SEXUALLY

AND ASEXUALLYMost sexual reproduction is

triggered by environmental stress

Asexual ReproductionMitosis

Sexual ReproductionMeiosisZoosporesPlus and minus gametesZygospore

Water Molds

Kingdom ChromalveolataDivision Heterokontophyta: Phylum Phaeophyta – Brown Algae

Phylum Phaeophyta

1500 species of Brown algae

Mostly marine and include seaweed and kelp

All are multicellular and large (often reaching lengths of 147 feet)

Individual alga may grow to a length of 100m with a holdfast, stipe and blade

Photosynthetic pigments

• chlorophyll a & c

• carotenoids

• xanthophylls (e.g. fucoxanthin)

Sargassum polyphyllum

Sargassum echinocarpum

Phaeophyta: Brown Algae

Turbinaria ornata

Padina japonica Hydroclathrus clathratus

Algal macrophyte structure

Brown Algae

Macrocystis -- Kelp

Macrocystis -- Kelp

Brown algae

Laminaria

Egregia

Postelsi

Photosynthetic Pigments

chlorophyll a

carotenoids

phycobilins

Mostly multicellular, marine forms.

Abundant in warm, tropical coastal waters.

Not all are red in color

Phylum Rhodophyta

Kingdom Protista Phylum Rhodophyta

4000 species of RED Algae

Most are marine

Smaller than brown algae and are often found at a depth of 200 meters.

Contain chlorophyll a and C as well as phycobilins which are important in absorbing light that can penetrate deep into the water

Have cells coated in carageenan which is used in cosmetics, gelatin capsules and some cheeses

Phylum RhodophytaCalcareous algae

Hypnea chordacea

Asparagopsis taxiformis

Galaxaura fastigiata

Acanthophora spicifera

Ahnfeltia concinna

Phylum Rhodophyta

Phylum Rhodophyta – Red Algae

Corallin

Palmari

Mazzaella

Phylum Rhodophyta – Red Algae

Harvesting from the sea

The harvest of seaweed for culinary delights

 7000 species altogether in world’s oceans600 different species of algae in Hawaii

Limu were important to early Hawaiians

More than 70 different kinds were usedEaten fresh used as spices or medicinesused in religious ceremonies in Hawaii

Food Source in Hawaii

• Toothpaste

• Beauty creams

• Paints

• Medical products- like bacterial culture plates, time-release pills, and dental impression gels

Certain alga can be used to make agar or as stabilizer in gelatin and ice cream:

Use: sugar, milk, irish moss or euchima, Chondrus, Porphyra and Rhodymenia- blend and boil.

Thickener and help smooth these items:

• Many foods and milk-products

Phycocolloids

Algin from brown algae

Carrageenan from red algae

phycocolloids from red and brown algae