Dust storms in the Sahara sustain life in the Atlantic Ocean

Science Daily: Research at the University of Liverpool has found how Saharan dust storms help sustain life over extensive regions of the North Atlantic Ocean. Working aboard research vessels in the Atlantic, scientists mapped the distribution of nutrients including phosphorous and nitrogen and investigated how organisms such as phytoplankton are sustained in areas with low nutrient levels.

They found that plants are able to grow in these regions because they are able to take advantage of iron minerals in Saharan dust storms. This allows them to use organic or ‘recycled’ material from dead or decaying plants when nutrients such as phosphorous – an essential component of DNA – in the ocean are low.

Professor George Wolff, from the University’s Department of Earth and Ocean Sciences, explains: “We found that cyanobacteria – a type of ancient phytoplankton – are significant to the understanding of how ocean deserts can support plant growth. Cyanobacteria need nitrogen, phosphorous and iron in order to grow. They get nitrogen from the atmosphere, but phosphorous is a highly reactive chemical that is scarce in sea water and is not found in the Earth’s atmosphere. Iron is present only in tiny amounts in sea water, even though it is one of the most abundant elements on earth.

“Our findings suggest that Saharan dust storms are largely responsible for the significant difference between the numbers of cyanobacteria in the North and South Atlantic. The dust fertilises the North Atlantic and allows phytoplankton to use organic phosphorous, but it doesn’t reach the southern regions and so without enough iron, phytoplankton are unable to use the organic material and don’t grow as successfully.”….

A dust plume off the west coast of Africa, NASA, Wikimedia Commons