NEW YORK ( TheStreet) -- The latest estimate of U.S. gross domestic product for the January to March period has been revised down to growth of 1.8% from an earlier estimate of 2.4%. The Commerce Department attributed the revision down to less consumer spending, a decrease in exports and softer business investment. Consumer spending, which accounts for about two-thirds of the GDP figure, rose at a 2.6% annualized pace during the period, down from the 3.4% pace estimated in the previous report. Consumer spending had grown at a 1.8% rate in the fourth quarter of 2012. According to Reuters, economists had expected the GDP report to be unchanged. The revision marks the third estimate for the first quarter. Carnival Corp. ( CCL) announced it is replacing its CEO Micky Arison. Arison, who has held the post since 1979, is the son of the company's founder, Ted Arison. He will continue to serve as chairman, while fellow board member Arnold W. Donald will take over as CEO. Carnival Cruise Lines has come under fire after a string of bad incidents have damaged the company's reputation. Last year, the Costa Concordia's sinking off the coast of Italy killed 32 people, while earlier this year passengers of the Carnival Triumph endured what were described as terrible conditions after the ship was left stalled without power in the Gulf of Mexico for days after an engine room fire. Shortly after, a backup emergency diesel generator failed on the Carnival Dream and the company was forced to cut the trip short and fly all of the ship's more than 4,000 passengers back to Florida from St. Maarten. Carnival announced Arison's departure as the company released second-quarter profit of $41 million on lower fuel and administrative costs. That's up from $14 million the company earned during the same period last year.