Solid-state ³¹P NMR reveals the biological organophosphorus compounds as the dominant phosphorus species in Saharan dust aerosols

Phosphorus is a critical nutrient affecting primary productivity across all ecosystems. Many regions worldwide are limited or co-limited by phosphorus availability, which can be alleviated through atmospheric deposition. Dust is known to be a key external source of phosphorus in ecosystems, assumed to be in the form of various insoluble inorganic minerals. We show that this view is largely incomplete and here we present conclusive evidence, that organic phosphorus as diesters, primarily associated with biological materials. Phosphate diesters significantly correlated with soil bacteria found in dust, implying a direct link with microbial soil communities, without excluding the eukaryotic cells. Phosphate diesters in dust, along with abundant alkaline phosphatase, may contribute 70% to daily primary productivity in the eastern Mediterranean, highlighting the potential of organic phosphorus substrates present in dust as airborne microorganisms to impact the biogeochemistry of oligotrophic environments via atmospheric deposition. (Figure presented.)