This is a reminder that  TOMORROW, Thursday Feb 24,  Dr. Jim  Kirchner   will be  giving a seminar in the Water Institute Distinguished Scholar Seminar Series.     
Thursday, February 24, 2011
Speaker:   Dr. James Kirchner, Director of the Swiss Federal Institute for Forest, Snow, and Landscape Research, Davos, Switzerland
Seminar Title:  Hydrological Processes Revealed by High-frequency Chemical Dynamics Spanning the Periodic Table
Time:  3:00 PM - 4:00 PM
Location:  209 Emerson Alumni Hall
Abstract: Catchment tracer studies have typically suffered from a stark mismatch of measurement timescales: water fluxes are typically measured sub-hourly, but their chemical signatures are typically sampled only weekly or monthly. More intensive measurement campaigns usually last only for short periods, such as individual storm cycles. At the Plynlimon catchment in mid-Wales, however, precipitation and streamflow have now been sampled every seven hours for nearly two years, and analyzed for water isotopes and more than 40 chemical tracers spanning the periodic table.

Here we explore these unique tracer time series, and compare them to longer-term (~20 years) but less frequently sampled (weekly) hydrochemical data from the same catchment. The high-frequency sampling reveals clear diurnal cycles in many chemical species, including some that are not normally thought to be biologically controlled. Passive tracers such as chloride and water isotopes are very strongly damped in streamflow relative to precipitation, implying that the catchment stores and mixes volumes of water that are much larger than individual storms, on timescales that are much longer than the intervals between events. However, other chemical species show strong coupling to streamflow on timescales of hours, implying that the catchment can rapidly re-set the chemical signature of "old water" in response to changes in the flow regime. The implications of these observations for catchment flowpaths, runoff generation, and biogeochemical processes will be discussed.  

Dr. Kirchner's research explores connections between terrestrial and aquatic environments, and linkages between physical, chemical, and biological processes. His research group seeks to answer questions such as: How does rainfall become runoff? How is the chemistry of natural waters shaped by subsurface transport and mixing, by chemical reactions with soils and rocks, and by biological processes? What can we learn about these processes at the scale of the whole landscape, by observing the signals that they impart to streams? How do ecological interactions among organisms shape their evolutionary development? His work typically combines field observations, simple mathematical models, and novel analyses of environmental data.  

Dr. Kirchner will be available to meet with interested students and faculty on the morning of Thursday February 24th.  Please contact Jim Jawitz ([log in to unmask]) or Wendy Graham ([log in to unmask]) if you are interested in meeting with him

Wendy Graham, Ph. D.
Carl S. Swisher Chair in Water Resources
Director UF Water Institute
PO Box 116601
University of Florida
Gainesville, Florida 32611-6601

Phone 352-392-5893 x 2113
Email  [log in to unmask]