Impact of Fugitive Methane Emissions on Ecosystem Services Across a Gradient of Shale Gas Extraction to Natural Gas DistributionEPA Grant Number: F13F31263
Title: Impact of Fugitive Methane Emissions on Ecosystem Services Across a Gradient of Shale Gas Extraction to Natural Gas Distribution
Investigators: Hendrick, Margaret
Institution: Boston University
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2014 through September 1, 2016
Project Amount: $84,000
RFA: STAR Graduate Fellowships (2013) RFA Text | Recipients Lists
Research Category: Fellowship - Environmental Monitoring , Academic Fellowships
As the United States shifts away from oil and coal and develops its sizable shale gas reserves, the carbon (C) budgets associated with extracting, producing and distributing natural gas have come into sharp focus, especially as leaks from natural gas systems are the highest anthropogenic CH4 emissions by source. Despite extensive research that characterizes the C sequestration and CH4 oxidation services that soil biota and vegetation render, the effects of these services have not yet been evaluated locally or regionally with respect to the United States’ natural gas industry. This research will characterize the effect of fugitive CH4 emissions on the ecosystem services of C storage and CH4 oxidation rendered by vegetation and soil across a gradient of shale gas extraction and natural gas distribution. By collecting and integrating ecological, biogeochemical and atmospheric data, this study aims to improve the quality of management and valuation of ecosystem services across the interdependent communities that produce and consume natural gas.
Soil, soil biota, vegetation and flux sampling will be performed in targeted communities in the Marcellus Shale Formation and within the greater metropolitan area of Boston, Massachusetts, where subterranean CH4 emissions are known to be elevated. As Boston is one of the oldest cities in the United States, with an equally aged natural gas distribution infrastructure, it provides an ideal environment in which to investigate the effects of pervasive natural gas leaks on urban ecosystems. Field sampling will occur during the growing season when trees are fully leafed out and soil biota are most active. A smaller set of winter samples will be taken to gauge seasonal variation. To study the same field processes under controlled conditions, greenhouse experiments will be conducted to measure the response of soil, soil biota, vegetation and total CH4 flux to treatments with known volumes of natural gas. By measuring microbial and vegetation processes, this research will quantify the impact of CH4 on above-and belowground C storage and CH4 oxidation. Flux chamber and landscape level CH4 sampling will assess whole-ecosystem CH4 flux across a rural to urban gradient of shale gas production and natural gas distribution, respectively.
Soils represent an extensive sink for atmospheric C, with soil biota oxidizing both atmospheric CH4 and CH4 that migrates up through the soil profile. Vegetation,especially trees, also represents a sizable sink for atmospheric C, and fugitive CH4 emissions negatively affect tree health and survivorship. It is likely that CH4 emissions from shale gas extraction and natural gas distribution will increase the proportion of methanotrophic bacteria in soil microbial communities and the potential for CH4 oxidation. Conversely, it is likely that CH4 emissions will decrease vegetation survivorship, growth rate, photosynthetic capacity and overall C storage potential. Total, relative CH4 flux to the atmosphere from shale gas extraction and natural gas distribution is therefore expected to change relative to the capacity of soil and vegetation in urban and rural ecosystems to render these climate regulation services.
Potential to Further Environmental/Human Health Protection
As the global population has just surpassed 7 billion and current C emissions are the largest on record, more attention than ever must be paid to mitigating the impact of climate change. Characterizing the effects of fugitive CH4 emissions in the United States is crucial because natural gas is central to this nation’s current energy program, and leaks from natural gas systems are the highest anthropogenic CH4 emissions by source. Data that fully characterize and quantify currently unvalued ecosystem services provided by soils and vegetation in response to sustained CH4 enrichment are urgently needed to guide policy that better manages natural gas fuels, improves urban and rural ecosystem health and reduces potent greenhouse gas emissions.