Question

Why might aquatic ecosystems have inverted biomass pyramids?

Answer 1

Hint: Ecological pyramids give a graphical representation of ecological parameters at a successive trophic level which may be upright or inverted. An inverted pyramid consists of a base with a small number of producers and a large number of consumers.

Complete Answer:
Biomass represents the amount of living matter present in the form of fresh or dry weight. In the aquatic ecosystem, the main producers are diatoms and phytoplanktons which have high annual productivity but their life span is short that's why it is less than than the primary consumers. Hence the pyramids which get formed are inverted or spindle-shaped.

Additional Information:
In the case of the pyramid of biomass, the biomass is maximum in producers, only 10-20% of biomass get passed from producer level to herbivore level and the rest of the biomass gets used up in respiration and may get wasted. Because of this, the biomass at a higher trophic level becomes smaller and smaller. The pyramid of biomass does not deal with the size or number of individuals present in the population of each trophic level and it only deals with the total living matter.
The demerit of a pyramid of biomass is its value change in different periods of years depending on the production and the rate of formation and accumulation of biomass does not take into consideration.

Note:
The inverted pyramid always occurs in the case of number and biomass where either size or turnover of producers is large.
The passage of biomass in each trophic level is explained by Lindeman by 10% law, which operates with small variations at the level of food transfer.