Cruise operator Carnival has lowered its full-year guidance after surging oil prices and turmoil in the Arab world.It now predicts earnings per share of $2.50 to $2.60 for the full year, sharply lower than the previous envisaged range of $2.90 to $3.10.Carnival provided initial guidance in December but says it now sees an additional $0.40 coming off earnings due to the higher fuel prices, while the Arab turmoil will result in a five cents reduction.On the plus side, the quarter to 28 February was ahead of expectations, with earnings per share coming in at $0.19. The company had issued guidance of $0.15 to $0.19.