Many species of marine zooplankton feed on phytoplankton within aquatic ecosystems. Marine biologists analysed the energy flow within a specific coastal reef ecosystem. They estimated that the energy in the zooplankton (primary consumers) trophic level was 620 000 J m−2 yr−1620\,000\text{ J m}^{-2}\text{ yr}^{-1}620000 J m−2 yr−1. The energy within the phytoplankton (producers) trophic level was 750%750\%750% greater than that of the zooplankton.
Calculate the energy in the phytoplankton trophic level in kJ m−2 yr−1\text{kJ m}^{-2}\text{ yr}^{-1}kJ m−2 yr−1.
Calculate the percentage efficiency of the energy transfer from phytoplankton to zooplankton. Give your answer to two significant figures.
37 exam-style questions on OCR A A Level Biology Ecosystems. Each one has a worked solution and a mark scheme showing where the marks go.