Thousands of dead crabs and mysterious deposits of black sand have littered the Thanet coastline.

Environmental experts believe the cold weather is again to blame for the deaths of velvet swimming crabs, which have been found at Palm, Walpole and Westbrook Bays.

In January 2010, the dead bodies of 30,000 to 40,000 of the crabs - also known as devil crabs - came ashore.

Volunteer coastal warden, Tony Sykes said: "We suspect that climate change and warmer weather has lured the crabs towards the shoreline.

"They could also be attracted to these waters looking for kelp, to feed on.

"We believe the sudden temperature drop causes the crabs to suffer from hypothermia and die."

Beach walkers at Viking Bay have also discovered large deposits of black sand.

Thanet geologist Dr Alasdair Bruce said: "My first thought was that it may be some sort of oil contamination but I am very pleased to say it wasn't. The sand itself is naturally black."

Dr Bruce said it was likely the sand, containing iron pyrite, was washed up by shifting currents during the winter.