1. By: Marie-Louise Posch

2. Kelp Kelp – general term for 124 species of brown algae. Classified in the Kingdom Chromista or Protista. http://www.youtube.com/watch?v =Y9eyK6C9nDA (0:28) http://www.youtube.com/watch?v =Y9eyK6C9nDA http://www.youtube.com/watch?v =naYu4m3b6cw (3:04) http://www.youtube.com/watch?v =naYu4m3b6cw Kelp Forest

3. Structure The kelp plant has three parts: the blade (the leaf-like structure), the stipe (the stem-like structure), and the holdfast (root-like structure) Holdfasts grip substrates Blades are buoyed by air bladders Do not dry up at low tide because cell walls contain a mucilaginous, water retaining material Kelp

4. Function Kelp grows in forests, which can be made of more than one species Provides habitat and food for marine life including fish, invertebrates, marine mammals, and birds A good source of protein, iodine, and iron Protects the body from heavy toxic metals The sodium alginate in kelp helps prevent absorption of radioactive strontium 90

5. Brown Algae The largest, most complex type of algae Contains chlorophyll a and c The pigment fucoxanthin gives it its color Air bladders help the blades float to allow for maximum sunlight absorption. Brown Algae

6. Structure Have chloroplasts surrounded by four membranes, suggesting an origin between basal eukaryotes and another eukaryote Develop into multicellular forms with differentiated tissues, but they reproduce by flagellate spores and gametes Brown Algae

7. Function Food source for fish, gastropods, and sea urchins. Benthic (bottom-dwelling) organisms benefit when pieces of it sink to the sea floor Common uses include food thickeners, stabilizers, and fillers. Also used in pharmaceuticals Contains chemicals called alginates that are used to thicken certain products like toothpaste and ice cream.

8. Review Questions What are the three parts of a kelp plant? blade, stipe, and holdfast What is the function of an air bladder? help the blades float to allow for sunlight absorption Name some common uses of brown algae by people food thickeners, stabilizers, pharmaceuticals, and fillers Name two ways kelp benefits marine life? Food source and habitat How does brown algae reproduce? by flagellate spores and gametes What is unique about the structure of brown algae? Have chloroplasts surrounded by four membranes