Litterfall mercury deposition in Atlantic forest ecosystem from SE – Brazil

Litterfall is believed to be the major flux of Hg to soils in forested landscapes, yet much less is known about this input on tropical environment. The Hg litterfall flux was measured during one year in Atlantic Forest fragment, located within Rio de Janeiro urban perimeter, in the Southeastern region of Brazil. The results indicated a mean annual Hg concentration of 238 ± 52 ng g−1 and a total annual Hg deposition of 184 ± 8.2 μg m−2 y−1. The negative correlation observed between rain precipitation and Hg concentrations is probably related to the higher photosynthetic activity observed during summer. The total Hg concentration in leaves from the most abundant species varied from 60 to 215 ng g−1. Hg concentration showed a positive correlation with stomatal and trichomes densities. These characteristics support the hypothesis that Tropical Forest is an efficient mercury sink and litter plays a key role in Hg dynamics.

► The litter production from an Atlantic Forest was measured by one year.
► Concentration and flux of mercury was measured from these litter samples.
► The Hg concentrations from 5 trees were taken.
► Correlations between the data found and meteorological and anatomical plant parameters were confronted.
► The high Hg values found and their distribution points to a great sequester potential from this biome.