New Harvard Forest Publication: Bog Research Reveals Useful Indicators of Atmospheric Deposition

Geographic trends in surface water chemistry and leaf tissue nutrients may reflect gradients of nutrient limitation and broad-scale anthropogenic inputs. Harvard Forest Senior Ecologist Aaron Ellison and his colleagues at the University of Vermont measured nutrient and metal concentrations in pore-water and in leaf tissues of three common bog plant genera - leather-leaf (Chamaedaphne calyculata), northern pitcher plant (Sarracenia purpurea), and peat moss (Sphagnum spp. in 24 bogs in Massachusetts and Vermont. Macronutrient and trace heavy metal concentrations were very low. Dissolved organic carbon (DOC), dissolved organic nitrogen (DON), Cu, Mg, NO3 Al and K in pore-water increased from the northwest (northwestern Vermont) to the southeast (Cape Cod and eastern Massachusetts near Boston), a gradient of increasing human population density and urbanization. In contrast, pore-water concentrations of SO4 and Al were highest in the western sites, and SO4 concentrations increased with elevations, reflecting atmospheric inputs from the Ohio River Valley leading to increased acidic eposition and causing Al to be leached from soils. Because bogs are naturally low in nutrients and do not receive substantial inputs from surrounding groundwater, the chemical signatures and nutrient stoichiometry of specific bog plants may provide useful indicators for assessing spatiotemporal changes in atmospheric deposition. This work provides baseline information for developing such indicators.

Gotelli, N. J., P. J. Mouser, S. Hudman, S. E. Morales, D. Ross, and A. M. Ellison. 2008. Geographic variation in nutrient availability, stoichiometry, and metal concentrations of plants in ombrotrophic bogs in New England, USA. Wetlands 28: 827-840.