Baltimore Ecosystem Study Institute of Ecosystem Studies

2017 BES Annual Meeting Presentation and Poster Abstracts

Declines in methane uptake in forest soils in the northeastern United States
Ni, Xiangyin
Co-Authors: Xiangyin Ni and Peter Groffman

Abstract: Forest soils are a sink for atmospheric methane (CH4) and play an important role in modulating global CH4 budget. Monthly soil to atmosphere net CH4 fluxes in urban and rural forests in the Baltimore Metropolitan area, MD were measured from 1998 to 2016. Annual soil CH4 uptake decreased by 62% and 53% in urban and rural forests over the 18 year study period, and CH4 uptake was 46% lower in urban forest than that in rural forest. This decrease, which occurred despite marked declines in nitrogen deposition and increases in atmospheric CH4 concentration and temperature (which should increase uptake), appears to be driven by increases in precipitation, soil moisture and/or soil leaching flux. We conclude that the current global soil CH4 sink may be declining and overestimated.