Question

Can the organisms of any trophic level be removed without causing any damage to the ecosystem? Will the impact of removing all the organisms in a trophic level be different for different trophic levels?

Answer 1

No, the organisms of no trophic level can be removed without causing damage to the ecosystem, as removing them can disturb the food chain.
Yes, the impact of removing all the organisms in a trophic level will be different for different trophic levels. Suppose the producers, who belong to the first trophic level, are removed, no organism belonging to the higher trophic levels will be able to exist, as the food and energy for the higher trophic levels are provided by the producers.
If consumers such as deer are removed from their trophic level, consumers such as lions, which eat deer, will die because of the unavailability of food. Hence, the population of lions will be reduced.
If consumers such as lions are removed from their trophic level, then there will be no predator control over the population of deer. Thus, the deer population will increase, leading to an excessive grazing of grass.