Project: Nitrate Processing at the SWI

Unlocking the Transient Storage Blackbox: Revealing the Role of Less-Mobile Porosity in Hyporheic Denitrification and Greenhouse Gas Production

Derived Publications

Dehkordy FMP, Briggs MA, Day-Lewis FD, Singha K, Krajnovich A, Hampton TB, Zarnetske JP, Scruggs C & Bagtzoglou A (2019). Multi-scale preferential flow processes in an urban streambed under variable hydraulic conditions. Journal of Hydrology. 10.1029/2018WR022823

Hampton TB, Zarnetske JP, Briggs MA, Singha K, Harvey JW, Day-Lewis FD, Dehkordy FMP & Lane JW (2019). Residence time controls on the fate of nitrogen in flow-through lakebed sediments. Journal of Geophysical Research: Biogeosciences. 10.1029/2018JG004741

Briggs MA, Day-Lewis FD, Dehkordy FMP, Hampton TB, Zarnetske JP, Scruggs C, Singha K, Harvey JW & Lane JW (2018). Direct observations of hydrologic exchange occurring with less-mobile porosity and the development of anoxic microzones in sandy lakebed sediments. Water Resources Research 54, 4714–4729. 10.1029/2018WR022823

Conceptual Model of a stream
hyporheic zone (Briggs et al., 2015)

Link to Zarnetske Lab Research Page

This project is broadly exploring denitrification at the surface-groundwater interface. Because of long residence times and ample supply of nutrients from surface waters, this interface is strongly reducing at depth/distance along flow-path, and favorable to denitrification. We are exploring whether biogeochemical or hydrologic conditions govern bulk function of this interface in reducing inorganic nitrogen, and what variations lead to export of nitrous oxide, a denitrification bi-product and potent greenhouse gas. This work is being coupled with numerical models of interface properties and geophysics to explore embedded less-mobile porosity quantity and structure.

Field site at Snake Pond on Cape Cod, MA

A rainy day on Cape Cod, from left to right: Farzaneh MahmoodPoor Dehkordy (UConn), Courtney Scruggs (UConn), Tyler Hampton, Erin Seybold (Duke), Jay Zarnetske, Martin Briggs, Kamini Singha

Field work Summer 2016 took place in a groundwater flow through lake on Cape Cod, MA, and piloted the controlled biogeochemical and hydrologic modifications, as well as the geophysical methods.

Field work during Summer 2017 took place in the Ipswich River watershed in MA, adjacent to the Plum Island LTER.

(Photo credit Kamini Singha) Sawmill Brook in
Burlington, MA. Left to right: Sinchan Roy 
Chowdhury (MSU),  Marty Briggs (USGS), 
Ashton Krajnovich (Mines), Farzaneh 
MahmoodPood Dehkordy (UConn), 
Tyler Hampton

Michigan State Students Sinchan
Roy Chowdhury and Tyler Hampton 
at Sawmill Brook.

Project: Exploring the effect of carbon and DOM quality on SWI nitrogen cycling

Exploring changes in carbon reactivity and composition, and the effect on the fate of nitrate, at a stream sediment-water interface

This work was conducted to explore how dissolved organic carbon (DOC) derived from different organic matter sources degraded within the sediment water interface (SWI), and how its reactivity or 'lability' affected nitrogen cycling and denitrification products within the SWI. Field work consisted of push-pull experiments at Augusta Creek, in Hickory Corners, MI, and additional laboratory studies were conducted by Joe-Lee Cullin and undergraduate Rachel Geiger at Michigan State. This work was supported by a Kellogg Biological Station LTER Summer Research Fellowship and a GSA Summer Research Grant, as well as the NSF Research Experiences for Undergraduates Program.

Joe Lee-Cullin and Tyler Hampton
sampling during Push-Pull experiments 
in Augusta Creek, Summer 2017

Joe Lee-Cullin and Rachel Geiger
collecting flocculated organic matter 
from Augusta Creek for use in batch reactor
studies of DOM quality and reactivity