H2S microsensor profiling conducted alongside the destructive sampling of Chesapeake Bay sediments during incubation experiments at Horn Point Lab from 2018-12-01 to 2019-01-31 (NCEI Accession 0291917)

This dataset contains chemical data collected from 2018-12-01 to 2019-01-31. These data include H2S and depth core. The instruments used to collect these data include Unisense H2S microsensor. These data were collected by Sairah Malkin of University of Maryland Center for Environmental Science as part of the "Collaborative Research: Probing the Metabolic and Electrical Interactions of Cable Bacteria in Anoxic Sediments (Anoxic Sediment Bacteria Interactions)" project. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2022-11-14.

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

Microsensor Profiling H2S

Dataset Description:
Acquisition Description:
The source material was collected from Chesapeake Bay (38.55505 N, 76.42794 W) (mesohaline), water column depth 26 meters, sediment horizon 0-10 centimeter below sea floor.

Incubation conditions: 16 degrees Celsius, S=15.5, dark, aerated.

Incubation Set-up: Sediments were homogenized and packed into polycarbonate core liners, sealed with a stopper at the bottom, and open to aerated aquarium water at the top. In a subset of cores, a polycarbonate filter (pore size 0.2 microns) was secured at 0.5 cm depth, to prevent downward growth of cable bacteria in these treatments. Sediments were incubated for up to 46 days. At 6 time points, microsensor profiles were measured, followed by destructive sampling.

Porewater extraction : Sediments were sectioned at 0.5 cm depth increments in an anaerobic glove bag under nitrogen atmosphere. Porewaters were separated by centrifugation (3500 rpm for 10 minutes), and filtered (0.2 micron) and aliquoted in the anaerobic glove bag. Samples for ferrous iron measurements were preserved with trace-metal grade nitric acid (final pH < 2).

Microsensor Profiling: High-resolution microsensor profiling of oxygen (O2), pH, and hydrogen sulfide (H2S) was performed on replicate sediment cores with 1 profile made per sediment core per analyte, using commercial microsensors operated with a motorized micromanipulator (Unisense A.S., Denmark). Oxygen sensor data were calibrated with a 2-point calibration using air-saturated water and anoxic zone of sediments. pH sensors were calibrated with a 3-point NBS buffer calibration. Sulfide (SumH2S) was calibrated with 5-point calibration using NaS2 (0-300 micromolar), and corrected with pH at the corresponding depth. Detailed methodology is given in Malkin et al. 2014.