Look at the diagrams at your table and answer the questions BIOMAGNIFICATION Look at the diagrams at your table and answer the questions

Biomagnification – Video on DDT and bald eagle: higher concentrations of a particular chemical, such as the pesticide DDT, are reached in organisms higher up the food chain, generally through a series of prey- predator relationships Examples: DDT and the bald eagle; PCBs and Lake Crabtree TOP CONSUMERS are most impacted Questions 1-2 (diagram 2) Video on DDT and bald eagle:

Diagram 1 At which trophic level does pcbs in the lake have the most effect on? top consumer Why do you think this would be? pcbs become more concentrated as they move up the food chain 2. What trophic level do the lake trout occupy? secondary/tertiary consumer What organism(s) are the producers? phytoplankton/algae

Diagram 3 Assume each alga consumers 10 units of mercury…How much mercury would concentrate in the mayfly nymph if each nymph ate 10 units of algae? 100 units (10 x 10) Assume the sunfish eats 10 mayfly nymphs. How much mercury accumulates in them? 1000 units (10 x 100) 3. Assume the heron eats 10 sunfish. How much mercury accumulates in them? 10,000 units (10 x 1000)

In summary… BIOMAGNIFICATION…. The concentration of chemicals in aquatic ecosystems (pcbs, mercury, etc) tends to increase in the tissues of organisms at higher levels in the food chain THEREFORE…TOP CONSUMERS (USUALLY THE BIRDS OF PREY) ARE MOST IMPACTED BY THIS PHENOMENON THE BIRD EGGS TEND TO BE FRAGILE…THUS PREVENTED SUCCESSFUL REPRODUCTION IN THE SPECIES

Lake Crabtree & PCBs read the pamphlet & answer the following What are PCBs? What happens to PCBs in the environment? How did PCBs get into Lake crabtree and other nearby water systems? Why did Wake County adopt the “catch & Release” practice in crabtree creek? What are some of the human health concerns if people eat fish from Lake crabtree? How do pcbs impact wildlife in and around Lake crabtree?