How many phytoplanktons are needed for one Dolphin weighing 300 kilograms to grow in the Black Sea?

According to the rule of the ecological pyramid, only 10% of the energy goes to the next trophic level. Roughly speaking, the body needs to eat 10 kg of food to gain 1 kg.

1) Let’s compose the simplest food chain:

Phytoplankton – zooplankton – fish – dolphin.

2) For a dolphin to gain 300 kg, it is necessary to eat 10 times more fish:

300 * 10 = 3000 kg or 3 tons.

3) For this, the fish needs to eat 3 tons * 10 = 30 tons of zooplankton.

4) Zooplankton for such biomass should eat 30 * 10 = 300 tons of phytoplankton.