Why animals at the top of the food chain particualrly at the risk from poison in the environment?

Question

Which organisms is at a higher trophic level: dolphins or planktons? What is the relationship between trophic level of an organism and concerntration of pesticides in its body?

Thank you for answering!

Answer 1

1. This is biological magnification. The concentration of poison in the environment gets higher and higher as it goes up the food chain. The poisons are kept in the bodies of the animals that eat them. They are not broken down or eliminated. So a predator that is higher up the chain gets a lot of the poison from its food.

2. Picture trophic levels as starting at the bottom and working their way up. So plankton is at the bottom, and dolphins that eat fish that eat plankton are at a higher trophic level.

3. The higher the trophic level, the higher the concentration of pesticides in the body.
Example: little fish - low
big fish that ate the little fish - higher
eagle that ate the big fish - higher yet

Answer 2

animals at the higher end of the food chain (eg dolphin) are at risk of bioaccumulating toxins. this is particularly the case for marine life. low level feeders (particularly filter feeders such as plankton) take in some toxins. these are eaten by larger animals which accumulate these toxins. eventually the largest animals accumulate these toxins.