Q55.2-1ITD - Campbell Biology

Question

What percentage of the solar energy that reaches the marsh is incorporated into gross primary production? Into net primary production?

Step-by-Step Solution

Answer

The solar energy entering the marsh is used for primary production; approximately 5.8% of the total energy is incorporated within the gross primary production, and around 1.1% of energy is incorporated in net primary production.

Step 1: Ecosystem

The term ecosystem is used for describing the biological unit in which a geographical unit is studied along with all the life forms present in it and other abiotic factors of that area. Depending on the abiotic factors, the ecosystem can be of various types; the two broad types are terrestrial and aquatic.

Step 2: Prime source of energy

In any ecosystem, the autotrophic organisms generate food by using the energy from solar radiation, and the heterotrophic organisms rely on the autotrophs either directly or indirectly. This implies that energy from the sun’s radiation is the prime energy source in an ecosystem.

Step 3: Solar energy incorporation into primary production

Primary production refers to the synthesis of food by plants (or other autotrophs). In this case, a total of 600,000 kcal per (m² ∙ yr) enters the marsh, and the gross primary production is 34,580 kcal per (m² ∙ yr), and the net primary production is 6,585 kcal per (m² ∙ yr).

Thus, the percentage of solar energy incorporated within the ecosystem as gross primary production is $\frac{34,580}{600,000}\times 100=5.8\%$

The percentage of solar energy incorporated as net primary production is $\frac{6585}{600,000}\times 100=1.1\%$