6. Limiting Nutrients


Marine Ecosystem

1. Introduction
2. Phytoplankton
3. Carbon in the Sea
4. Carbon Cycle
5. Conditions for Life
6. Limiting Nutrients
7. Nutrient Distribution
8. Life in the Sea
9. Food Webs

When I was growing up, my father would rent a small boat at the harbor so we could go fishing one Sunday each month.

After returning home with the day's catch, we could clean the fish and bury the remains in his vegetable garden, which was his pride and joy.

Fish remains provide an excellent fertilizer, indeed natural fish emulsion is very popular with gardeners to this day.

The nutrients in the sea are recycled in a similar manner, much to the benefit of the entire ecosystem.

When organisms die, the remains decompose in the mid and deep waters by bacterial activity (so-called decomposers).

The result is that the deep waters contain a vast reservoir of nutrients that can be tapped by upwelling to return to the surface.

Data Table

Let's examine this process by using the table of chemical and temperature data above and the graph paper in your expedition worksheet.

Make plots of water depth against the concentration of:

1. Nitrogen (N) as Nitrate (NO3--)

2. Phosphorous (P) as Phosphate (PO4---)

3. Temperature (oC)

Make sure that understand the relationship of the nutrient distribution to the layering of the water masses.

©Copyright 1999
March 13, 1999

Send to Don Reed

Department of Geology
San Jose State University

What is the distribution of limiting nutrients with water depth?