MRI: Acquisition of Liquid Water
Isotope Analyzer Capability for Advancing Hydrologic Research in the
Baltimore Ecosystem Study LTER
C. Welty, K. Szlavecz, L E. Band, P. M. Groffman, S. Kaushal, S.S.
Schwartz, A.J. Miller, D. Bain, M. Baker, J. Duncan, K. Belt, M. Lorah
Intellectual Merit of Proposed Activity
University of Maryland Baltimore County (UMBC) and institutions participating in the Baltimore Ecosystem Study (BES) Long-Term Ecological Research (LTER) project propose to acquire a liquid water isotope analyzer for use in hydrologic and biogeochemical watershed research. The instrument would be housed at the BES field headquarters on the campus of UMBC. This acquisition will complement existing analytical capabilities and greatly enhance BES investigators’ ability to interpret data needed to close urban water and nutrient budgets and to quantify flow paths, fluxes, and stores of water in the urban environment. The instrument will enable determination of 18O/16O and 2H/1H ratios in liquid-water samples and processing of many samples inexpensively on a routine basis. These naturally occurring stable isotopes of hydrogen and oxygen behave as conservative tracers in hydrologic systems. Isotopic ratios are altered by phase changes (e.g. evaporation and condensation) resulting in distinctive high frequency variability in precipitation enrichment ratios. Absent significant phase changes, hydrologic stable isotope concentrations only change through mixing, enabling the distribution of catchment-scale flow paths to be estimated from the time series of observed isotope concentrations in flow and precipitation.
BES research efforts that would benefit from the instrumentation include: evaluating the interaction between stream base-flow and urban infrastructure; determining sources of water in urban storm flows; evaluating the impact of engineered stormwater infiltration practices on groundwater recharge; and quantifying components of urban evapotranspiration. These efforts will support fundamental advances in our understanding of urban hydrology, complementing ongoing work at field sites with an unusually rich array of field installations and modeling capabilities. Neither UMBC nor the BES owns a liquid water isotope analyzer. Samples are currently sent off-site to commercial laboratories on a per-sample fee basis.
Broader Impacts of Proposed Activity
The proposed acquisition represents a multi-institutional, multidisciplinary collaboration. Twelve investigators from five universities, two federal agencies, and one research institute spanning the fields of hydrology, biogeochemistry, ecology, geomorphology, and environmental engineering are involved. A much wider use of the instruments beyond this proposal lead group is expected since the BES LTER is composed of 34 co-PIs and over 70 collaborators. It is also anticipated that the instruments or data from the instruments will be used by dozens of undergraduate and graduate students and post-doctoral associates in research and coursework under the mentorship of the faculty members and scientists involved. The proposed work will have the broader impact of contributing to the research infrastructure of the BES by providing access to instrumentation that is currently unavailable on site.
UMBC, the BES, and partner institutions are committed to recruiting underrepresented groups into their science and engineering programs. A major focus at UMBC is bringing the research experience to the undergraduate student especially female and minority students. UMBC scholarship programs and the Cary Institute of Ecosystem Studies REU are explicitly targeted to minority students, and UMBC hosts summer undergraduate research programs designed to introduce students, including minority students, to research. UMBC is also host to a NSF IGERT “Water in the Urban Environment”. Graduate students in this program are mentored by BES faculty and are working on research that would benefit from acquisition of the instruments. Through the BES, an extensive outreach educational program with inner-city Baltimore schools is in place that can be utilized for this project as appropriate. For example, educational modules on the soil, water, and ecosystems of Baltimore City are available for school teachers that can be supplemented with data analyzed by BES scientists using the proposed liquid water isotope analyzers.