The Amazon rainforest might be a little less green if not for a massive plume of Saharan dust that drifts across the Atlantic Ocean each year, according to a new, multi-year study by NASA scientists.
NASA used light pulses from its CALIPSO satellite to measure the transatlantic dust cloud in three dimensions. They found that wind carries roughly 182 million tons of Saharan dust out to sea each year. The cloud sheds roughly 50 million en route to South America, but the remainder fans out over the Amazonian basin and the Caribbean Sea, dusting the soil with 22,000 tons of phosphorus, a nutrient commonly found in commercial grade fertilizer.
Amazingly, the special delivery of plant food almost perfectly matches the amount of phosphorous the Amazonian jungle loses through heavy rains and run-off water.
"This is a small world," said study author Hongbin Yu, "and we're all connected together."