Which of the following ecosystems will be more productive in terms of primary productivity? Justify your answer. A young forest, a natural old forest, a shallow polluted lake, alpine meadow.

Primary productivity:

Primary productivity is defined as the synthesis of biomass per unit area per unit time. It depends upon several factors like nutrients, temperature, moisture, and photosynthetic activity of the plants.

Young forest vs old forest:

Since a young forest is still developing it may contain fewer trees compared to the old forests. The young forests therefore will not absorb the solar radiation as much as old forests that contain a well-established community of trees. Old forests are therefore more productive as compared to young forests.

Polluted lake:

A polluted lake does not support the growth of plants. Hence, it has low productivity.

Alpine meadow:

Alpine meadows have a short growing period. They do not have trees but contain simple plant communities like grasses hence, they have low productivity.

Hence, old forests will be more productive in terms of primary productivity