Aerosols, landscape impact carbon dioxide

DURHAM, N.C., Dec. 9 (UPI) -- North Carolina scientists found the level of particles in the air along with the nature of the landscape impacts the rate at which plants absorb carbon dioxide.

The study looked at diffuse radiation -- indirect sunlight scattered by clouds, haze, or something else -- and found higher levels of diffuse radiation resulted in higher rates of carbon absorption. Aerosols, which also scatter light, increased the amount of carbon absorbed by the land.

But the land itself made a difference in the results. Increased amounts of aerosols over forests and croplands resulted in the surface areas below becoming carbon sinks while increased amounts of aerosols over grasslands resulted in surface areas becoming carbon sources.

The team, based at North Carolina State University, hypothesizes the difference is linked to the amount of shade provided by tree and plant leaves in forests and croplands. Limited shading in grasslands changes the ground surface temperature. Plants may slow their rate of photosynthesis to preserve water causing less CO2 to be absorbed and, relatively, more CO2 to be effectively emitted. That would make the surface area a carbon source.

The research was published in Geophysical Research Letters.