1. Nutrient Cycles in Marine Ecosystems Part II
Section 4

2. Limited Productivity
Inorganic nutrients (ex: nitrate and phosphate ions) are essential for growth of primary producers
Productivity of primary producers will affect productivity of higher trophic levels
Example: upwelling – high productivity

3. Benguela upwelling system

4. Removal of Nutrients Sink to sea floor In feces
Detritus (decaying organic materials); organisms die
Loss of nutrients from surface water
Will only return to surface by upwelling
Slow decomposition on sea bed (floor) due to cold/lack of oxygen

6. Removal of Nutrients Incorporated into coral reefs
Deposition of calcium carbonate for growth of corals

7. Removal of Nutrients Removed by harvesting
Removing/eating fish and other marine organisms

9. Nutrient Biological Uses
Nitrogen
Make proteins; synthesis of amino acids
Carbon
Synthesis of all organic materials (ex: carbohydrates, proteins)
Magnesium
Make chlorophyll for plants
Calcium
Production of bones, corals and shells
Phosphorus
Production of bones and synthesis of DNA

10. Summary of ways in nutrients are cycled in marine systems
Nutrients derived from both
Removal (3)
Figure 4.1
Summary of ways in nutrients are cycled in marine systems

11. In Summary Fertilizers(N ,P and K)- plant growth.
The level of dissolved nutrients increases from animal feces
Surface water often lack nutrients because feces and dead matter tend to settle to the bottom of the ocean.
Most decomposition is thus at the bottom of the ocean.
Plants must be at the surface for the light. Nutrients are returned to surface waters by a special type of current called 'upwelling' and it is in these areas of upwelling that we find the highest productivity of marine life.

12. Website References