Biogeochemical data from sediment cores collected from a shallow, sandy subterranean estuary (STE) in Virginia USA from 2018 to 2019 (NCEI Accession 0291441)

This dataset contains chemical data collected from 2018-04-10 to 2019-01-16. These data include Ammonium, Nitrite, and nitrate plus nitrite. The instruments used to collect these data include Isotope-ratio Mass Spectrometer, Nutrient Autoanalyzer, and Vibracore. These data were collected by Craig Tobias of University of Connecticut and Bongkeun Song and Iris C. Anderson of Virginia Institute of Marine Science as part of the "Collaborative Research: Cryptic nitrogen cycling in the anoxic subterranean estuary (Subsurface cryptic N cycle)" project. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2023-03-27.

The following is the text of the dataset description provided by BCO-DMO:

Sediment Core Biogeochemistry

Dataset Description:
Acquisition Description:
These data were collected during 2018-2019 from a sandy subterranean estuary (STE) located in Gloucester Point, Virginia, USA (37.248884, -76.505324). In four seasons, a vibracore collected a sediment core roughly 100 centimeters (cm) in length from the mid-tide line of the beach during low tide. Cores were sectioned into ten-centimeter increments. Extractable nutrient concentrations in potassium chloride extracts were analyzed for NOx (nitrate + nitrite), nitrite, and ammonium with a Lachat autoanalyzer. Core sections were used in isotope tracer incubations with 15N-labeled substrates to measure potential denitrification and anaerobic ammonium oxidation (anammox) rates. Briefly, 1 gram (g) of the composited sediment from each 10 cm section was used in sediment slurry incubation experiments. Samples were incubated for 6, 12, or 24 hours in sealed, helium-flushed 12 milliliter (mL) exetainer vials (Labco) at the measured in situ temperature. Denitrification rate incubations were amended with 100 nanomoles ¹⁵NO₃⁻ (99 atm%, Cambridge Isotope Laboratories, Inc.), and ²⁹,³⁰N₂ products were measured using a gas bench isotope ratio mass spectrometer (IRMS, Delta V Plus, Thermo Fisher Scientific, Waltham, MA). To measure potential anammox rates, 500 nanomoles of ¹⁵NH₄⁺ (99 atm%, Cambridge Isotope Laboratories, Inc.) and 100 nmoles ¹⁴NO₂⁻ were added to the sediment slurries; the production of ²⁹N₂ was measured by IRMS. N₂ production rates were calculated using the methods described by (Song and Tobias, 2011). All incubations were conducted in duplicate.