Phosphorous in the dust is necessary for photosynthesis, and now scientists have shown the mineral comes from fossilized bones and scales from organisms a continent away.
About 5,000-10,000 years ago Megalake Chad covered north-central Africa, with a surface level 36 stories taller than it is today. Remains of the fish that swam there settled into part of the lake bed called the Bodélé Depression, which "is probably the largest single source of wind-blown dust in the world," according to NASA.
The researchers used X-rays to identify the bone and scale phosphorous from Bodélé dust.
"The Bodélé fish phosphorus is like that found in fish bone meal that gardeners use as a fertilizer," Karen Hudson-Edwards from Birkbeck, University of London told BBC News.
The organic phosphorous won't last forever, the scientists report. It's not clear how long it will take for the sediments in Lake Chad to completely erode. But when the time comes, the Amazon will come to rely on rock-based phosphorous, which may negatively affect the rainforest.
From Discovery News
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