In the aftermath of the Gulf oil spill, what is the effect of oil on invertebrates, animals like jellyfish, clams, crabs, sea stars, and plankton? The scope of the damage is more easily observed among birds and large animals, but Dr. Christopher Mah suggests what we don't see may be more widespread and devastating. Dr. Mah is an Invertebrate Zoologist with the Smithsonian National Museum of Natural History. He writes the Echinoblog www.echinoblog.blogspot.com , a blog focusing on Echinodermata, which includes sea stars, sea urchins, brittle stars, sea cucumbers, feather stars, and other spiny skinned animals. To learn more, read Dr. Mah's Ocean Portal guest blog post The Invisible Loss: The Impacts of Oil You Do Not See - ocean.si.edu/blog/invisible-loss-impacts-oil-you-do-not-see/.