Question

Which among the following statements is/are incorrect?

• A. In general, the transfer of energy from one trophic level to the next is in the order of 10%
• B. Open ocean and deserts are less productive than ocean- land -interface regions
• C. NPP is maximum in a tropical forest and average in a temperate forest
• D. The productivity of aquatic ecosystems is much higher as compared to the terrestrial ecosystem in context of total biosphere productivity

Answer 1

The correct option is D The productivity of aquatic ecosystems is much higher as compared to the terrestrial ecosystem in context of total biosphere productivity

Lindeman's 10% law limits the number of trophic levels in the ecosystem is less, as only 10% of the energy of lower trophic level is transferred to the organism of the higher trophic level unidirectional manner. Only 10% of the net productivity is entrapped by the herbivores; similarly carnivores and top carnivores are able to retain only a 10% of the energy from the preceding food chain level.

Productivity refers to the rate of biomass production, the rate at which sunlight is captured by the producers for the synthesis of energy rich organic compounds.

Different plant species inhabit different areas. Their different photosynthetic ability and the different nutrients available in the area affect the primary productivity in different ecosystems.

The Arctic region is really cold and has less sunlight and because of this, the number and organic matter of the plants (producers) is less, productivity is also less.

Desert has the highest sunlight availability but has the least rainfall, thus only cactus and desert plants grow. This accounts to comparatively less productivity. Similarly, in the open ocean, limited light penetrates deep down to the profundal zone below the photic zone and hence the amount of organic matter accumulated per unit area per unit time is less.

In tropical and temperate regions, the rainfall and sunlight are way better than the arctic and desert regions, thus this increases productivity. NPP of tropical forests is maximum and that of temperate forests is average.

Since aquatic plants have less access to sunlight under deep waters, when compared to terrestrial ecosystems, the productivity of aquatic ecosystems is low. Despite occupying more than 70% of biosphere their productivity is about 55 billion tonnes while terrestrial ecosystems have a productivity of 115 billion tonnes.