Atmospheric dust is a global nutrient source for plants via foliar uptake

Area of Science:

• Plant Biology
• Environmental Science
• Soil Science

Background:

• Atmospheric mineral dust is recognized as a key nutrient source for marine ecosystems.
• Terrestrial plant nutrition has been primarily attributed to soil nutrient uptake via roots.
• The role of atmospheric dust in terrestrial plant nutrition is largely overlooked.

Purpose of the Study:

• To investigate the direct nutrient uptake pathway of atmospheric dust by terrestrial plants through leaves.
• To quantify the contribution of foliar dust nutrient uptake to plant nutrition in different ecosystems.
• To assess the significance of this pathway under current and future climate scenarios.

Main Methods:

• A Mediterranean field study simulating dust events was conducted.
• Plant macro- and micronutrient concentrations were analyzed after dust application.
• Dust deposition estimates, soil nutrient data, and regional flux data were integrated.
• Leaf microenvironment's role in dust dissolution was examined.

Main Results:

• Dust application significantly increased plant nutrient concentrations.
• The leaf microenvironment, with its mild acidity and organic acids, aids dust dissolution and nutrient release.
• Annual foliar dust nutrient input can constitute up to 17% of iron fluxes in the Western US and 12% of phosphorus fluxes in the Eastern Amazon.
• During dust events, daily foliar nutrient input can rival soil-derived fluxes.

Conclusions:

• Plants directly acquire nutrients from atmospheric dust via leaves, establishing a novel terrestrial nutrient uptake pathway.
• Foliar dust uptake plays a significant role in plant nutrition, particularly in nutrient-limited and dust-impacted environments.
• This pathway's importance may increase with climate change-induced shifts in dust emissions, necessitating its inclusion in ecosystem models.