Scaling of Nitrogen Cycle Controls Throughout a River Network
Title: Collaborative Research: Understanding the Scaling of N
Cycle Controls Throughout a River Network
Project Duration: 1-Oct-2006 - 30-Sep-2009
investigating the controls on nitrogen (N) cycling throughout the
Ipswich River watershed in northeastern Massachusetts. The
River watershed landuse is a mix of urban, agrictultural, and reference
types. To understand how aquatic networks control N exports, we
require knowledge of what controls N reactivity across the entire range
of river sizes that comprise the river network. Much research has been
devoted to quantifying N cycle processes in small headwater streams,
with a recent emphasis on denitrification. It remains unknown whether
the controls in
small streams apply to larger river reaches. In particular, the role of
the hyporheic zone is potentially critical, yet scaling rules
describing changes in transient storage zone/hyporheic
characteristics and associated N cycle processes have yet to be
1) Characterize the major interactions involving surface water hydraulics, hyporheic flow and nitrate concentrations in regulating rates of aquatic denitrification and nitrate retention across stream orders;
2) Determine how the spatial distribution of denitrification and nitrate retention interacts with the distribution of nitrate inputs to define river network control of N exports to the coastal zone.
Location: Our field sites are within the Ipswich River watershed in Massachusetts (www.mass.gov).
This project is funded through the National Science Foundation's Ecosystem Sciences Program.
This material is based upon work supported by the National Science Foundation under Grant Nos. DEB 06-14350. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation