In the past six months, the numbers of dolphin and sea turtle deaths in the Gulf of Mexico (map) have risen, and some fish that inhabit the Gulf's coral reefs have developed abnormalities. (Read more about the Gulf oil spill anniversary.)

Yet projects to document and measure the oil's effects on Gulf marine life are still in the very early stages, scientists caution. Preliminary results may not be available for months, and it may be several years before any kind of scientific consensus is reached.

(See an interactive of the Gulf's layers of life in