Algae

1. Algae Kelp/ Brown Algae, Green Algae, and Red Algae

2. Kelp/Brown Algae • Is often referred to as seaweed • Found along temperate coastlines • All types are multicellular and most are marine • Found in the intertidal zone  are submerged during high tides and exposed to atmosphere at low tides Kelp- a type of brown algae that grows in “forests” and is known to grow extremely fast, reaching 30 to 80 meters high • Uses • Used for food  sushi • Alginic Acid- the gel like substance found in brown algae is extracted and used in a variety of things including slimming aids, water/fire proofing, ice cream, cosmetics, and making impressions (dentistry/ prosthetics),

3. Structure of Brown Algae • Thallus- a seaweed body that is plantlike but lacks true roots, stems, and leaves • Holdfast- anchors algae to the ground • Stipe- stemlike structure that supports blades • Blades- leaflike structure that provides most of the surface for photosynthesis ( some types of brown algae are equipped with a flotation device that keeps the blades near the surface of the water) • Some types of seaweed are have cell walls made of cellulose and gel forming polysaccharides that protect them from the waves and give them a slimy feeling

4. Red Algae • Red algae are red because of an accessory pigment called phycoerythrin which belongs to the family of pigments known as phycobilins. Another organism that has this accessory pigment is cyanobacteria. • Most abundant in warm coastal waters in tropical oceans but there are some freshwater species • Depending on the depth of the water, the pigmentation of the algae will differ  red algae that is very deep with be almost black, at moderate depths it will be bright red, and close to the surface it will be a light greenish due to more chlorophyll that is doing photosynthesis

5. Red Algae • Agar ( a gel forming substance; a polymer made up of subunits of galactose) is often extracted from red algae and used as an ingredient in many Asian desserts, helping grow microbiological cultures, thickener for soups and in ice cream Often used and grown in Asia due to climate conditions

6. Chlorophytes in a mutual relationship with a fungus are known as lichens Green Algae • Over 7000 species of green algae • Volvox- a type of green algae that lives in a colony (up to 50,000) that is spherical in shape • Has an extracellular matrix made of glycoprotein • Has an eyespot that allows them to move towards the light using their flagella • Euglena- a unicellular flagellate protist that can alternate between autotrophic and heterotrophic and is often found in quiet inland waters • Moves toward light using its eyespot (known as phototaxis) • Has a protein coat • If conditions are unfavorable, it will become dormant

7. YouTube Video • Ulva • Most commonly known as sea lettuce • Multicellular green algae that grows in almost every saltwater body in the world • Grow in the littoral zone  close to shore where nutrients are abundant • Used for food locally • http://www.youtube.com/watch?v=7Q40s7Pm-Nw