MIAMI, FLORIDA (AFP) - Florida's vast coral reefs could suffer disastrous consequences if they are doused with oil and chemical dispersants from the huge Gulf of Mexico spill, scientists warn.

Satellite images show it is likely that the slick leaking from a ruptured well pipe will be swept into the Loop Current which would drag the toxic crude to the southern end of the Florida peninsula, where its coral reefs are located. The current then rushes northward off the east coast of Florida.

Residents of the Florida Keys - a chain of small islands at the bottom of the state famous for fishing and diving - were in a panic Tuesday when tar balls washed up on area beaches.

Tests were being carried out to determine whether the tar balls came from the Gulf spill or were instead waste from a passing ship.

The possibility of oil washing up along Florida's coastline is alarming news for the Sunshine State, which has a 60-billion-dollar tourist industry that could be crippled by the environmental menace. The state had 80 million visitors in 2009.

The potential threat is especially dire for the Keys, a spot that attracts divers keen to visit the area's coral reefs, the largest on the planet after reefs in Australia and Belize.

Crude oil and dispersants could bleach and kill coral, said Richard Dodge an coral reef expert at Florida's Nova University.

"Dispersants and dispersed oil are detrimental to coral reefs and so dispersants should not be used around coral reefs," Dodge said.

Oil alone is toxic to corals. "Effects range from heavy mucous production by the coral causing stress, disruption of reproductive tissues, bleaching, and mortality," Dodge said.

Water dilutes the oil's toxicity, but when chemical dispersants are used the oil is concentrated in highly toxic droplets. "Dispersed oils is much more harmful to corals than oil only," Dodge said.

"This can have an increased detrimental effects on corals because the oil can become more available to coming in contact with the coral tissue," he said.

The amount of damage to the coral will depend on the level of exposure to the oil and dispersants, he added.

BP says some 5,000 barrels - 210,000 gallons of crude - is spewing each day from the wreckage of the Deepwater Horizon rig, which sank after an April 20 explosion that killed 11 people. Independent experts however fear the flow rate is many times higher.

Oceanographers said on Monday they believed that once the oil is inside the Loop Current it could take about a week for it to collide with the Florida Keys.