| This is a sea urchin (Lytechinus variegatus) in the flume. The red stream you see is mussel juice that has red dye in it so we can visualize the odor plume. Notice how the red-dyed cue looks similar to the smoke coming off a cigarette. That whispiness is due to turbulence--either in the air (for the cigarette), or in the water (for the mussel juice). Increasing the water velocity increases the turbulence. Animals must be able to perceive the signal to find the food source, though with increased turbulence this task may become more difficult. |
