1 / 13

Denitrification in Delaware Bay Tidal Marshes and Creeks

Denitrification in Delaware Bay Tidal Marshes and Creeks. February 2011 Mike Owens, Jeffrey Cornwell Chesapeake Biogeochemical Associates & UMCES Horn Point Laboratory Delaware Estuary Science and Environmental Summit. Sediment Fluxes.

kathleengriffin
Télécharger la présentation

Denitrification in Delaware Bay Tidal Marshes and Creeks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Denitrification in Delaware Bay Tidal Marshes and Creeks February 2011 Mike Owens, Jeffrey Cornwell Chesapeake Biogeochemical Associates & UMCES Horn Point Laboratory Delaware Estuary Science and Environmental Summit

  2. Sediment Fluxes • July 19, 2007: Cores collected for subtidal fluxes at 4 stations (triplicate cores) • July 23, 2007, April 27, 2008: Cores collected for marsh fluxes (2 marsh cores, 1 creek core). Standard fluxes carried out both time, plus two levels of NO3- addition in 2007 • We utilized our “standard” core incubation procedures and measured fluxes of ammonium, nitrate, di-nitrogen, oxygen and soluble reactive phosphorus.

  3. Study Goals • Measure net nutrient fluxes at the sediment-water interface of Murderkill River, creek and marsh environments • Utilize N2:Ar approach to measure denitrification to examine denitrification in high and low nitrate seasons • Compare denitrification rate estimates to other nitrogen sinks (i.e. burial) and to estimates of N input

  4. Atmospheric DIN Wetland Plant Community DIN + PN Surface Water Nitrogen N2-N Point/Non-Point N Inputs 3 2 DIN DIN 4 Wetland Soil DIN + PN 1 • Measured Parameters • NOx flux into soil • NOx flux into soil • NH4+ efflux from soil • Soil denitrification • Nitrogen burial Groundwater DIN Exchange 5 “Permanent” Burial

  5. Putting Microbes to Work Denitrification requires 1) reducing conditions (no oxygen) and 2) a source of nitrate (NO3-) In many environments, nitrate come from the oxidation of ammonium (nitrification) This process represents a bona fide loss of nitrogen; burial, incorporation into fish and washout at the bay mouth are the other major sinks for nitrogen

  6. Marshes

  7. Nitrate Addition Experiment July 2007

  8. Conclusions • Marsh nitrogen burial and denitrification rates are similar. Both could account for an important portion of watershed N inputs. • Denitrification is similar in early spring to summer rates, despite different nitrate sources (summer nitrification, spring water column nitrate)

More Related