| Contributors | Affiliation | Role |
|---|---|---|
| Song, Bongkeun | Virginia Institute of Marine Science (VIMS) | Principal Investigator, Contact |
| Brush, Mark J. | Virginia Institute of Marine Science (VIMS) | Co-Principal Investigator |
| Piehler, Michael F. | University of North Carolina at Chapel Hill (UNC-Chapel Hill) | Co-Principal Investigator |
| Tobias, Craig | University of Connecticut (UConn - Avery Point) | Co-Principal Investigator |
| Ake, Hannah | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Measurements of nutrient flux and denitrification and DNRA rates in clam aquaculture sediments.
In May and July 2013, 16 randomly selected clam beds and 4 uncultivated sites and in November 2013, 7 randomly selected clam beds and 3 uncultivated sites were sampled at the Cheerystone Inlet of VA Eastern Shore. Uncultivated sites were located approximately 20 m from the clam beds, a distance chosen to reduce any influence of aquaculture on the control sediments and at a water depth similar to that of the clam beds. 60 cores were collected in May and July (20 total sites during each month), and 30 cores were collected in November (10 total sites). Cores were not treated as replicates, but were used to conduct concurrent incubations to measurement of denitrification and DNRA rates by isotope-pairing techniques. The details of methods are published in Murphy et al. (2016). DOI: 10.1002/lno.10305.
Nutrients and isotopic composition of N2 and NH4+ were used to calculate the fluxes and rates as reported in Murphy et al (2016). DOI: 10.1002/lno.10305.
BCO-DMO Processing Notes:
- column names reformatted to comply with BCO-DMO naming standards.
- nd used to replace all blank cells with no data.
| File |
|---|
nutrients.csv (Comma Separated Values (.csv), 12.97 KB) MD5:f93b3eab4c69ad9fb2c5592313adbf38 Primary data file for dataset ID 700800 |
| Parameter | Description | Units |
| month | Month that sampling took place | unitless |
| treatment | Treatment description | unitless |
| ID | PI issued ID | unitless |
| light_dark | Light or dark treatment | unitless |
| DIC | Concentration per hour | millimoles per meter squared per hour |
| Nox | Concentration per hour | micromoles per meter squared per hour |
| NH4 | Concentration per hour | micromoles per meter squared per hour |
| PO4 | Concentration per hour | micromoles per meter squared per hour |
| dark_DON | Concentration per hour | unitless |
| DO | Concentration per hour | millimoles per meter squared per hour |
| D14 | Concentration per hour | micromoles per meter squared per hour |
| DNRAt | Concentration per hour | micromoles per meter squared per hour |
| D15 | Concentration per hour | micromoles per meter squared per hour |
| Dw | Concentration per hour; Cherry WC Nox | micromoles per meter squared per hour |
| Dn | Concentration per hour; Cherry WC Nox | micromoles per meter squared per hour |
| DNRAw | Concentration per hour; Cherry WC Nox | micromoles per meter squared per hour |
| DNRAn | Concentration per hour; Cherry WC Nox | micromoles per meter squared per hour |
| Dataset-specific Instrument Name | IRMS |
| Generic Instrument Name | Isotope-ratio Mass Spectrometer |
| Generic Instrument Description | The Isotope-ratio Mass Spectrometer is a particular type of mass spectrometer used to measure the relative abundance of isotopes in a given sample (e.g. VG Prism II Isotope Ratio Mass-Spectrometer). |
| Dataset-specific Instrument Name | Core |
| Generic Instrument Name | Multi Corer |
| Dataset-specific Description | Used to collect core samples |
| Generic Instrument Description | The Multi Corer is a benthic coring device used to collect multiple, simultaneous, undisturbed sediment/water samples from the seafloor. Multiple coring tubes with varying sampling capacity depending on tube dimensions are mounted in a frame designed to sample the deep ocean seafloor. For more information, see Barnett et al. (1984) in Oceanologica Acta, 7, pp. 399-408. |
| Website | |
| Platform | shoreside Virginia |
| Start Date | 2013-05-01 |
| End Date | 2013-07-31 |
| Description | Cheerystone Inlet of the Eastern Shore of Virginia: N37°18’30” and W76°1’0” |
Extracted from the NSF award abstract:
Oyster reefs are biogeochemical hot spots and prominent estuarine habitats that provide disproportionate ecological function. Suspension-feeding eastern oysters, Crassostrea virginica, are capable of improving water quality and diminishing eutrophication by filtering nutrients and particles from the water and depositing them in the sediments. Remineralization of these deposits may enhance sedimentary denitrification that facilitates nitrogen removal in tidal estuaries. However, the scientific underpinning of oyster reef function has been challenged in various studies. In addition, recent studies of filter feeding invertebrates reported the production of nitrous oxide (N2O), a greenhouse gas, as an end product of incomplete denitrification by gut microbes. C. virginica could be another source of N2O flux from intertidal habitats. Preliminary work indicated substantial N2O production from individual oysters. The estimated N2O production from high density oyster reefs may exceed the N2O flux measured from some estuaries. With the new discovery of N2O emission and uncertainty regarding eutrophication control, the ecological value of oyster reef restoration may become equivocal.
This project will quantify N2O fluxes to understand the factors controlling N2O emission from oyster reefs. Sedimentary N processes will be examined to develop an oyster reef N model to estimate N2O emission from tidal creek estuaries relative to other N cycling processes. The PIs hypothesize that intertidal oyster reefs are a substantial source of N2O emission from estuarine ecosystems and the magnitude of emission may be linked to water quality. If substantial N2O flux from oyster reefs is validated, ecological benefits of oyster reef restoration should be reevaluated. This interdisciplinary research team includes a microbial ecologist, a biogeochemist, an ecologist and an ecosystem modeler. They will utilize stable isotope and molecular microbiological techniques to quantify oyster N2O production, elucidate microbial sources of N2O emission from oysters and sediments, and estimate seasonal variation of N2O fluxes from oyster reefs. Measurements from this study will be integrated into a coupled oyster bioenergetics-sediment biogeochemistry model to compare system level rates of N cycling on oyster reefs as a function of oyster density and water quality. Modeling results will be used to assess the relative trade-offs of oyster restoration associated with N cycling. They expect to deliver the following end products:1) estimation of annual N2O flux from oyster reefs as an additional source of greenhouse gases from estuaries, 2) a better understanding of the environmental and microbial factors influencing N2O and N2 fluxes in tidal estuaries, 3) transformative knowledge for the effect of oyster restoration on water quality enhancement and ecosystem function, 4) direct guidance for oyster restoration projects whose goals include water quality enhancement, and 5) a modeling tool for use in research and restoration planning.
| Funding Source | Award |
|---|---|
| NSF Division of Ocean Sciences (NSF OCE) |