Chapter 20, Problem 16PS

Interpreting Data In a classic study, John Teal measured energy flow in a salt marsh ecosystem. The table below shows some of his results.

Form of energy	Kcal/m2/yr	Efficiency of energy transfer (%)
Sunlight	600,000	n/a
Chemical energy in producers	6,585
Chemical energy in primary consumers	81

Data from: J.M. Teal, Energy Flow in the Salt Marsh Ecosystem of Georgia. Ecology 43: 614–24 (1962).

1. a. Calculate the efficiency of energy transfer by the producers. That is, what percentage of the energy in sunlight was converted into chemical energy and incorporated into plant biomass?
2. b. Calculate the efficiency of energy transfer by the primary consumers. What percentage of the energy in plant biomass was incorporated into the bodies of the primary consumers? What became of the rest of the energy (see Figure 20.27)?
3. c. How much energy is available for secondary consumers? Based on the efficiency of energy transfer by primary consumers, estimate how much energy will be available to tertiary consumers.
4. d. Draw an energy pyramid for the producers, primary consumers, and secondary consumers for this ecosystem (see Figure 20.28).