Dust from the Sahara Desert provides life with a vital nutrient to life at the bottom of the marine food chain. Without the iron carried by this mineral cloud, ocean phytoplankton would not be able to thrive. The more time dust spends in the atmosphere and the further it travels, the more of its iron converts into a form readily available in the biosphere, according to new research from the University of California, Riverside.

“Just as iron fertilization can affect life in oceans and continents, transported iron appears to drive biological processes,” says biogeochemist Timothy Lyons. “This study is a proof of concept that confirms that iron-related dust can have serious impacts on life at great distances from its source.”

Dust from the barren desert of North Africa is the largest source of airborne particles on Earth. Each year, winds move about 800 million metric tons westward to the Americas, carrying iron isotopes collected from the open surface of the desert.

The metal plays a vital role in the biochemical pathways that enable the conversion of atmospheric carbon into organic molecules. Although iron is essential for life, its availability is limited, meaning that the distribution of this nutrient largely determines where life can be found on Earth.

Not all forms of iron are readily used by living organisms. Atmospheric conditions can make a big difference on the menu of iron that eventually settles on the ocean surface.

“Dust reaching areas such as the Amazon basin and the Bahamas may contain iron that is particularly soluble and accessible to life due to its greater distance from North Africa and therefore longer exposure to atmospheric chemistry,” Lyons said. he explains.

Biogeochemist Bridget Kenley and her colleagues discovered this by analyzing drill cores taken from the ocean floor. They found that while the total amount of dust decreased as transportation distance increased, the amount of bioavailable iron dissolved in water actually increased with distance.

“This rate suggests that chemical processes in the atmosphere are converting less bioreactive iron into more accessible forms,” says Owens.

Thanks to its large mass of bioactive iron, the dust feeds a vast food chain thousands of kilometers from its source, fertilizing phytoplankton in the oceans as well as plants as far away as the Amazon. These two systems produce most of the oxygen we breathe. Previous studies have shown that these bioactive iron patterns overlap with areas of increased biological activity. This includes greater microbial activity on the surface of Caribbean coral reefs and fertilization of the Amazon region.

The seven-year study found that an average of 28 million metric tons of North African dust also supplied about 22,000 tons of fertilizer phosphorus to the Amazon River basin. Other studies have also shown that dust from Asia has been fertilizing Hawaii’s rainforests for thousands of years. Saharan dust clouds can also cause problems such as allergies in people due to their presence. They have the power to suppress even hurricanes.

Despite the barren origins of this high ground and the problems it can cause, the grains of the Sahara Desert carry the vital fuel for life on Earth, providing another example of how incredibly interconnected the physical processes on our planet are with the life that beckons us. home. This study was published on: Frontiers in Marine Sciences.