1. Photosynthesis in the Ocean 6H 2 O + 6 CO 2  C 6 H 12 O 6 + 6 O 2 Photosynthesis in the ocean depends on CO 2 and H 2 O (not limited!), nutrients, and light

2. Nutrients-- SeaWifs Satellite image

3. Primary Producers

4. Electromagnetic spectrum (light)

5. Wavelengths of light Different colors of light go different depths –Red goes away first –Blue goes away last (which is why the ocean looks blue!) Why would BLUE light penetrate more than RED light?

6. Wavelengths of light Different pigments absorb different colors of light –Chlorophyll a = purple and red light (mostly red) –Chlorophyll b = blue-green light –Phycoerythrins = blue light

7. Light Zones in the Ocean Euphotic Zone: Penetrates to about 600 feet, this is the zone where 95% of all primary plant growth takes place. Disphotic Zone: also called the TWILIGHT ZONE, no plant life, only animals adapted to very low light levels Aphotic Zone, also called the MIDNIGHT Zone, with no light at all.

8. Aphotic Zone Disphotic Zone Euphotic Zone

9. Depth Photosynthesis (mg C / m 3 / hour) Photosynthesis decreases with depth in the ocean

10. Depth Photosynthesis (mg C / m 3 / hour) Critical depth is depth where Respiration = Photosynthesis Respiration

11. Light Intensity (calories / cm 2 / min) Photosynthesis (mg C / m 3 / hour) Pmax (saturation point) Photoinhibition