Crabs that are blue need grass that is green. The sun provides light and warmth to land, air, and water. When light does not get to green plants, such as eelgrass, they wilt and die. Blue crabs and fish need the protection and oxygen the underwater plants in their habitat provide.
Blue crabs walk sideways.
Synopsis Students will observe that muddy water blocks sunlight. They will consider ways that soil might get into water and make inferences about effects on underwater grasses, crabs, and other animals. When sediment from soil erosion enters the Chesapeake Bay and its tributaries, it blocks sunlight that eelgrass and other submerged aquatic plants need. Without these underwater plants young aquatic animals lack protective habitat and sufficient dissolved oxygen. Show crab shells, seahorse, artificial eelgrass.