41. The second trophic level ( primary consumers ) is occupied by zooplankton which feed off the phytoplankton. 42. Certain isotopes can signify distinct primary producers forming the bases of food webs and trophic level positioning. 43. A numbers pyramid shows the relevant number of organisms that each trophic level occupies in an ecosystem. 44. These sharks occupy tertiary trophic levels . 45. If one species is significantly depleted, that will have an effect throughout the rest of the trophic levels . 46. Microalgae is the base of the food web and provide energy for all the trophic levels about it. 47. A biomass pyramid shows the total mass of the organisms that each trophic level occupies in an ecosystem. 48. An integrated aquaculture system consists of a number of species at different trophic levels of the food chain. 49. This energy stored in the organism represents the amount available to be passed on to the next trophic level . 50. It occurs when two or more species in a habitat affect shared natural enemies in a higher trophic level .
