Wednesday, All Day in Poster Hall
, Thursday, All Day in Poster Hall
(subject to change)
Roadways in the conterminous US are ubiquitous with 20% of the US within 150 m of a roadway, and nowhere more than 35 km from a roadway. Motor vehicles (mobile sources) are the dominant source of NOx in the US as a whole and of NH3 in urban areas. Atmospheric deposition is the largest source on N to our watershed, but because of retention is not the largest source to the estuary however with continued deposition this is expected to decrease. We used paired 150 m transects of bulk and throughfall precipitation collectors as well lysimeters, forest floor and foliage samples to assess the impact of near source N deposition on N retention near a moderately traveled road (10,000-18,000 vehicles day-1). In sites near the road, the N content of leaves and litter was greater; the C:N ratio of the forest floor was lower; more NO3- was collected in lysimeters and on ion exchange resins; and pH of both the forest floor and mineral soil was less than at the sites furthest from the road.
