Foliage Type Controls Mercury Input, Storage, and Release in the Boreal Forest
Abstract
Mercury (Hg) is a naturally occurring element with a complex biogeochemical cycle. Forests act as net sinks for both carbon (C) and Hg as foliage accumulates Hg with time. Litterfall represents a main input of C and Hg into forest soils. My aim was to investigate how foliage type (coniferous, deciduous) governs the input of Hg into forests with a field-based study that measured Hg accumulation over a growing season, and then investigate the storage and release of Hg from foliar tissues into soil with a laboratory-based incubation experiment. Results from the field-based study demonstrate deciduous leaves have more linear Hg uptake rates than conifer needles after the first growing season. Results from the incubation study suggest that Hg release is a function of decomposition influenced by litter type. Understanding how vegetation influences Hg cycles in forests is important for understanding how climate change will impact forest Hg cycles.