Transcript Algae
Algae Algae • • • • • • diverse simple mostly aquatic mostly photosynthetic Belong to the kingdom Protista Eukaryotic – So they have a nucleus and membrane bound organelles - Photosynthesis takes place in chloroplasts - They can be either - Green - Brown - Red How are they different from plants? • No flowers – Simple reproductive structures • Lack leaves, roots, and stems Diatoms • Unicellular organisms that are usually planktonic • Cell walls made of glass-like Silica • The glassy shell is called a frustule – Has two halves and resembles a box Diatom Reproduction Frustules get smaller and smaller. Usually asexual reproduction Ooze • When diatoms die, their glassy shells sink to the bottom of the ocean creating diatomaceous ooze • Does that sound familiar? – Mined and used in things like • Swimming pool filters • Toothpaste • Temperature and sound insulators Dinoflagellates • Two flagella – one wrapped around a groove along the middle of the cell – One trailing behind it – Cell wall made of plates of cellulose Zooxanthellae • Special dinoflagellate that lives in close association with coral and other animals • In coral, they photosynthesize and the coral uses the nutrients released by them Special Dinoflagellates • Some are bioluminescent • Some release toxic substances during large blooms Pfiesteria • • • • Phantom dinoflagellate Parasite that feast on fish Cause open sores in fish Temporary memory loss in humans Protozoans (animal like protists) • Foraminiferans – Shell made of calcium carbonate – Pseudopodia to trap diatoms to eat Homotrema rubrum is a foram that is bright red and lives on corals. Very common in Bermuda; skeletons made the island’s famous pink beaches. Radiolarians • Spherical • Shells of silica • Pseudopodia to eat Ciliates • Many hair like extensions called cilia to move • Very common as freshwater Paramecium Multicellular Algae • Seaweed – Sometimes called macrophytes or macroalgae – Also eukaryotic – Can range from small to large – Kelp often form large forests underwater Structure • Lack true leaves, stems, and roots • Entire body is called the thallus • Leaf-like flattened portions are called blades • Pneumatocysts are gas filled chambers that keep blades close to surface to maximize photosynthesis • Some seaweed have a support called a stipe where blades originate • Holdfast holds thallus to ground Types of seaweed • Green algae – Most live in freshwater • Brown algae – Largest, most complex seaweeds – Kelp • Red algae – More marine red than brown and green combined Economic Importance • Mariculture: farming of seaweed is big in China, Japan, and Korea • Phycocolloids are gellatins used in many foods • Algin used to stabilize foods • And much more… Seagrasses • Not algae • Actually adapted land plants that live in water • Roots grow sideways under sediment • Provide homes to many organisms • Castro, Peter and Huber, Michael E. Marine Biology. New York: McGraw-Hill, 2007.