In the aftermath of the Gulf oil spill, what is the effect of oil on invertebrates like jellyfish, clams, crabs, sea stars, and plankton? The scope of the damage is more easily observed among birds and large animals, but Dr. Chris Mah, an invertebrate zoologist at Smithsonian's National Museum of Natural History, suggests that what we don’t see may be more widespread and devastating. To learn more about sea stars, urchins, brittle stars, sea cucumbers, feather stars, and other spiny skinned animals, visit the Echinoblog.