1. Phytoplankton Microscopic plants that drift in the upper waters of the oceans Use sunlight to produce their own food through the process of photosynthesis: CO 2 + H 2 O  C 6 H 12 O 6 + O 2 Carbon dioxide + water  sugar + oxygen

2. Phytoplankton, cont’d Are critical to all life on earth because they are the basis of food webs and generate most of the atmospheric O 2 When conditions are right (i.e., sufficient nutrients) they are capable of blooms – very rapid growth in numbers Are collected in funnel-shaped plankton nets towed behind research vessels

3. Plankton Nets

4. Types of Phytoplankton There are 3 main types: 1.Diatoms 2.Dinoflagellates 3.Coccolithophores

5. Diatoms Are the most dominant and productive phytoplankton As many as 12,000 species exist Have beautifully ornate shells made of silica which are unique to each species of diatom Used in silver polish, toothpaste, and for filtering beers, wines, and juices

6. Photos of Diatoms

7. Dinoflagellates Most have 2 flagella (whips) Some are capable of bioluminescence (producing light) Some cause “red tide” – they bloom so extensively that the water looks red Some release a neurotoxin that is stored in certain shellfish and causes Paralytic Shellfish Poisoning (PSP) in humans when shellfish are eaten

8. Photos of Dinoflagellates Red tide

9. Bioluminescence

11. Coccolithophores Are covered with discs made of calcium carbonate White Cliffs of Dover are fossilized coccolith deposits Can thrive in nutrient-poor waters where other phytoplankton cannot survive

12. Photos of Coccolithophores