1. Unicellular Marine Organisms and Algae

2. Archaebacteria and Bacteria Archaebacteria  From the Greek archaio meaning OLD  Extremophiles (live in environments that are inhospitable to most life)  Chemosynthesizers Bacteria  Old, but not as old as archaebacteria  Important group is cyanophytes  Also known as blue-green algae or cyanobacteria Believed to be organisms that created oxygen in the atmosphere Responsible for nitrogen fixation  Red cyanophytes responsible for flamingoes’ pink color

3. Diatoms: Background Info Most common organism found in the ocean Part of the ocean’s community of plankton (wanderers, meaning they drift, not swim) More accurately classified as phytoplankton Belong to the Kingdom Protista  Eukaryotic  Have organelles  Have chloroplasts  Cell walls of silica  Reproduce both sexually and asexually

4. Diatoms: Classification Classified by shape  Round diatoms are called centric diatoms  Pen-shaped diatoms are called pennate diatoms

5. Diatoms: Interesting Factoids Food source for many marine invertebrates and shellfish Can cause Harmful Algal Blooms (HABs)  Algal blooms are caused by a sudden increase in the diatom population  Referred to as brown tides  In the late 1980’s a brown tide devastated the scallop industry Collected by using a plankton net

6. Dinoflagellates: Background Info Often found near the ocean’s surface Larger than diatoms Belong to the kindgom Protista  Phylum Dinophyta (also called phylum Pyrrophyta or phylum dinoflagellata)  Most are autotrophs  Motile Use flagella

7. Dinoflagellates: Dangers Can cause Harmful Algal Blooms (HABs) Algal blooms caused by dinoflagellates are called red tides  Highly toxic  Substances are more toxic than cyanide Bioaccumulation in shellfish can cause seafood poisoning

8. Genus Noctiluca  Heterotrophic  Capable of bioluminescence  Emit light when agitated Genus Symbiodinium  Live on live coral polyps forming a mutualistic relationship Symbiodinium provides host with food via photosynthesis Coral provides nitrogenous wastes Coral could not exist without Symbiodinium Dinoflagellates: Interesting factoids

9. Green Algae: Background info Multicellular algae Most commonly known as seaweed Belong to phylum Chlorophyta Share many characteristics with land plants  Chlorophyll a (directly involved with photosynthesis)  Chlorophyll b (assists Chlorophyll a in capturing light) Approximately 7,000 species of green algae

10. Green Algae: Interesting Factoids Approximately 7,000 species of green algae Much simpler than plants  Do not have the system of roots, stems, veins that plants have Some have holdfasts  Holdfasts are appendages that look like roots but simply anchor the algae to rocks

11. Red Algae: Background info Consists of freshwater and marine algae Belong to phylum Rhodophyta  Over 4,000 species  Multicellular  They do not produce cellulose  Most have only chlorophyll a  Contain red pigments called phycoerythrins Allow algae to exist in deeper water Pigment absorbs blue light

12. Red Algae: Significance Important for coral reefs  Secrete a calcium carbonate shell which bond individual coral colonies and debris together  Holds the coral structure in one piece Some do not secrete calcium shells  Genera Chondrus (Irish moss) and Porphyra (Nori)  These are leaf-like and are harvested, dried, and eaten

13. Brown Algae: Background Info Belong to phylum Phaeophyta More structurally complex than other algae  Have holdfasts, blades, leathery flexible stipes,gas-filled pneumatocysts  blades = leaves  Pneumatocysts: keep blades close to the surface and sun  Get their distinctive olive-green/brown color to the pigment fucoxanthin

14. Brown Algae: Interesting Factoids 1,500 species Largest and most impressive is kelp  Giant kelp can grow 30 cm (11.8 in) per day and reach the surface from 24 m (79 ft)  Important because it forms the foundation for many temperate coastal ecosystems  Dominate the coasts of California, Mediterranean, and New Zealand Genus Sargassum  Do not have holdfasts  Form huge drifting rafts  Sargasso Sea in the center of the N. Atlantic have large amounts of sargassum