The energy transfer between trophic levels follows the 10% rule, where only about 10% of energy is transferred from one level to the next. However, producers (1st trophic level) typically convert only 1-2% of the solar energy they receive into chemical energy (biomass).

Given:

Total solar energy available = 1,000,000 J.

Producers capture ≈1% of this energy:
1%×1,000,000 J=10,000 J.

Energy at the 2nd trophic level (herbivores) = 10% of producers' energy:
10%×10,000 J=1,000 J=1 kJ.

Thus, the energy available at the 2nd trophic level is 1 kJ.