Phytoplankton like diatoms, dinoflagellates, and coccolithophores live near the surface of oceans and use sunlight, carbon dioxide, and nutrients like nitrogen and phosphorus to photosynthesize and grow. The Redfield ratio describes the optimal balance of these elements for phytoplankton growth, with carbon and nitrogen being taken up at a ratio of around 106:16 and carbon and phosphorus at around 106:1. Nutrient availability in different areas of the ocean is influenced by upwelling currents that transport nutrients from the thermocline to the euphotic zone where phytoplankton live.

1. Primary Productivity Nutrient Cycling Honors Biology – Edgar October 2011

9. NPP=GPP-R

14. phytoplankton Who are the Phytoplankton? Coccolithophore Diatoms Dinoflagellates

15. Thermocline Depth in meters 0 100 Nutrients Euphotic Zone or Mixed Layer Thermocline 0µM 5µM 10µM 200 0% 50% 100% Light 0° 10° 20° Temperature

16. Gulf of Maine Data: Wilkinson and Jordan Basins Wilk. Basin Jordan Basin

17. Redfield Nucleic Acids Lipids Proteins Carbohydrates CO 2 Light Nutrients (N, P, etc) The Redfield Ratio 106 Carbon : 16 Nitrogen : 1 Phosphorus Liebig’s Law: Growth of a “plant” is determined by availability of the single most limiting resource.

18. Duck?

26. Nutrient Cycle