NAPLES — A year after the worst oil disaster in U.S. history slimed the Gulf of Mexico, scientists say they are finding troubling signs of an ecosystem still reeling.

They say, though, it is too early to draw a definitive connection to the Deepwater Horizon explosion, which killed 11 rig workers last April.

Scientists are studying everything from the lowliest organisms to the Gulf's top predators to try to paint a picture of what is happening below the surface.

So far, they don't like what they see.

Red snapper caught in the northern Gulf are sick. Bottlenose dolphins are washing ashore with oil on them. Brown muck is covering bottom-dwelling creatures, some of which are deformed.

"We're certainly wondering if there is a connection or not," said Ben Flower, associate professor of oceanography at the University of South Florida in St. Petersburg. "It's a circumstantial case, but it's part of a good case."