Tourists and locals streaming to South Florida beaches will find fun in the sun, but also heaps of smelly sargassum seaweed. Sargassum, which forms in enormous floats out in the Caribbean Sea and off of Brazil is increasingly becoming a huge headache for Caribbean Islands, Mexico's Yucatan Peninsula and South Florida. The seaweed is growing at record rates due to climate change warming the ocean and nutrients from fertilizer and human and animal waste flowing into the sea. The sargassum floats in ocean currents until prevailing winds blow it ashore. In some areas, the seaweed accumulations are threatening local tourism. It can also threaten wildlife by de-oxygenating the water, making it hard for shore birds to find food, and sea turtle hatchlings to reach the water. The seaweed problem is expected to worsen until humans stop burning the fossil fuels -- coal, oil, and natural gas -- that are driving global and ocean warming.