Dataset: ETSP N2O
Deployment: AT15-61

ETSP N2O

View Data: For data, See Dataset Metadata Page: https://www.bco-dmo.org/dataset/821268

Principal Investigator:

Karen L. Casciotti (Woods Hole Oceanographic Institution, WHOI)

Student:

Noah Gluschankoff (Stanford University)

Contact:

Alyson E. Santoro (Woods Hole Oceanographic Institution, WHOI)

Analyst:

Matthew Forbes (Stanford University)

Matthew R. McIlvin (Woods Hole Oceanographic Institution, WHOI)

BCO-DMO Data Manager:

Dana Stuart Gerlach (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

Expression of Microbial Nitrification in the Stable Isotopic Systematics of Oceanic Nitrite and Nitrate (Microbial Nitrification)

Version:

Deployment Synonyms:

ETSP2010

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Description

These data were published as Figure 5 in Santoro et al. (2020).

Nitrate (NO3-) and Nitrite (NO2-) d15N and d18O data from the samples are available in the related dataset "ETSP NO3 and NO2 isotopes" (https://www.bco-dmo.org/dataset/903891).

Description of changes/updates contained in version 2 of this dataset:
Most depths were analyzed in duplicates from two bottles (i.e. one measurement of all isotopic variables and a concentration per bottle). This version (v2) contains each measurement in a unique column (i.e. d15n_alpha1, d15n_alpha2, etc.). A quality control (QC) flag was also added for each measurement using the SeaDataNet QC guidelines available at https://www.seadatanet.org/Standards/Data-Quality-Control.

Methods & Sampling

Dataset acquisition description

Seawater samples were obtained during the R/V Atlantis (AT15-61) and R/V Melville (MV1104) cruises from January to February 2010 and March to April 2011. Water samples were collected at discrete depths using Niskin bottle type rosette samplers equipped with either 24 bottles (10L) or 12 bottles (20L), and an SBE9plus conductivity-temperature-depth (CTD) sensor package (SeaBird Electronics, Bellevue, WA). This dataset's samples were collected from Niskin bottles into 160-milliliter (mL) glass serum vials, killed with saturated mercuric chloride, and crimp sealed with gray butyl stoppers. Prior to sealing, ~1 mL of sample was removed to allow room for sample expansion and to prevent the sample vessel from shattering upon warming.

In all cases, samples were extracted and analyzed using a custom automated purge and trap inlet system and normalized to an injection of calibrated pure N2O reference gas introduced prior to the elution of each sample peak (McIlvin & Casciotti, 2010). Isotope ratios were referenced initially to the calibrated N2O reference tank to create a set of 'ratio of ratios' (³¹Rsample/³¹Rreference, ⁴⁵Rsample/⁴⁵Rreference, ⁴⁶Rsample/⁴⁶Rreference). Next, the data were size corrected in reference to a calibrated 20 volt-second (Vs) peak area for a mass-to-charge ratio of 44 (m/z 44). Finally, 'scrambling coefficients' were applied to the isotopomer data to correct the measured 15Ra and 15Rb for the rearrangement of nitrogen atoms in N2O when the gas is ionized in the mass spectrometer ion source (Frame et al., 2014; Frame & Casciotti, 2010; Kelly et al., 2021). The isotope ratios of N and O atoms in N2O, ¹⁵Rsample or ¹⁸Rsample, respectively, are expressed in delta notation (δ), where the δ15N and δ18O are defined relative to the isotope ratios of certified standards: δ15N or δ18O = (Rsample/Rstandard - 1) x1000. The Rstandard values used for δ15N and δ18O are the ratios of 15N/14N and 18O/16O in atmospheric N2 and Vienna Standard Mean Ocean Water (VSMOW), respectively.

Data Processing Description

Dataset Processing Description

Data Processing:
CTD sensor data were processed using Seabird Electronics (SBE) Data Processing software using SBE recommended parameters, including the tau oxygen correction and oxygen hysteresis correction. Processing commands were applied in the following order: filter, alignctd, celltm, loopedit, wildedit.

Derived parameters (pottemp, aou, sigma_theta) were calculated in MATLAB using the CSIRO SEAWATER function library for MATLAB, ver 3.3 (22-Sept-2010).

Version 1:
(Version Date: 2020-08-18)
v1 BCO-DMO Processing:
- Added a conventional header with dataset name, PI name, version date.
- Adjusted parameter names to comply with database requirements.
- Combined year, month, day fields and adjusted timezone to create ISO date field.
- Units in parentheses removed and added to Parameter Description metadata section.
- Missing data identifier of 'NaN' replaced with 'nd'.

Version 2:
(Version Date: 2023-07-28)
Description of v2: This includes a further QC'ed version of the v1 data with six additional isotopic variables: d15n_alpha, d15n_beta, Site_preference (SP), d17O, and d18O. N2O samples were analyzed in duplicates, thus each analysis has an associated QC flag.
v2 BCO-DMO Processing:
- Imported original file named "ETSP_ENSO_N2Oisotope_BCODMO_230227.xlsx" sheet 1 into the BCO-DMO data system.
- Replaced missing data identifier of 'NaN' with blank/empty values, which is the default for csv files.
- Renamed "Presure" column to "Pressure".
- Filled in a value of "1" in the "flag_1" column per request of data submitter.
- Named the final file "821268_v2_etsp_n2o.csv".

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-0961098	NSF Division of Ocean Sciences

Instruments

Automated Purge and Trap System

Supplied Name: custom automated purge and trap inlet system

Supplied Description:

Instrument Type

Generic Name: Automated Purge and Trap System

Generic Description:

This equipment removes dissolved gases from the water samples, traps the extracted compounds on a cold trap and then heats the trap and injects the trapped gases into the gas chromatograph. It is automated and controlled by a laptop computer.

CTD Sea-Bird

Supplied Name: SBE9plus

Supplied Description:

Instrument Type

Generic Name: CTD Sea-Bird

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/130/

Generic Description:

Conductivity, Temperature, Depth (CTD) sensor package from SeaBird Electronics, no specific unit identified. This instrument designation is used when specific make and model are not known. See also other SeaBird instruments listed under CTD. More information from Sea-Bird Electronics.

Isotope-ratio Mass Spectrometer

Supplied Name: Thermo Fisher Delta V Plus

Supplied Description:

Instrument Type

Generic Name: Isotope-ratio Mass Spectrometer

Acronym: IR Mass Spec; IRMS

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/

Generic 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).

Niskin bottle

Supplied Name: Niskin bottle type rosette

Supplied Description:

Instrument Type

Generic Name: Niskin bottle

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/

Generic Description:

A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
ISO_Date_Local	Date of sampling in ISO 8601 format. Timezone was GMT-5 in 2010, GMT-4 in 2011	unitless	ISO_DateTime_Local
Latitude	Latitude of sample collection, South is negative	decimal degrees	lat
Longitude	Longitude of sample collection, West is negative	decimal degrees	lon
Station	Station number	unitless	station
Cast	Cast number	unitless	cast
Depth	Sample collection depth	meters (m)	depth
Salinity	Salinity	practical salinity units (psu)	sal
Temperature	Temperature	degrees Celsius	temp
Density	Seawater density	kilograms per cubic meter (kg/m^3)	density
Oxygen	Dissolved oxygen	micromoles per kilogram (umol/kg)	O2
Pressure	Pressure	decibars	press
Potential_Temp	Potential temperature	degrees Celsius	potemp
AOU	Apparent oxygen utilization	micromoles per kilogram (umol/kg)	AOU
sigma_theta	sigma-theta, Potential density anomaly	kilograms per cubic meter (kg/m^3)	sigma_0
sigma_T	sigma-T, Density anomaly	kilograms per cubic meter (kg/m^3)	sigma_t
d15n_alpha_1	First measurement of d15N alpha (inner nitrogen atom) in N2O in reference to atmospheric nitrogen gas, expressed in permille notation	permille	d15N
d15n_beta_1	First measurement of d15N beta (outer nitrogen atom) in N2O in reference to atmospheric nitrogen gas, expressed in permille notation	permille	d15N
SP_1	First measurement of N2O SP (site preference) in N2O in reference to atmospheric nitrogen gas, expressed in permille notation	permille	N2O
d15n_bulk_1	First measurement of d15N bulk in N2O in reference to atmospheric nitrogen gas, expressed in permille notation	permille	d15N
d17O_1	First measurement of d17O in N2O in reference to VSMOW, expressed in permille notation	permille	delta17O
d18O_1	First measurement of d18O in N2O in reference to VSMOW, expressed in permille notation	permille	d18O
N2O_nM_1	First N2O concentration measurement in nanomolar (nM)	nanomoles per liter (nM)	N2O
flag_1	Data quality control flag from SeaDataNet: https://www.seadatanet.org/Standards/Data-Quality-Control. 1 = good value; 2 = probably good value; 3 = probably bad value, 4 = bad value, 9 = missing value	unitless	q_flag
d15n_alpha_2	Second measurement of d15N alpha (inner nitrogen atom) in N2O in reference to atmospheric nitrogen gas, expressed in permille notation	permille	d15N
d15n_beta_2	Second measurement of d15N beta (outer nitrogen atom) in N2O in reference to atmospheric nitrogen gas, expressed in permille notation	permille	d15N
SP_2	Second measurement of N2O SP (site preference) in N2O in reference to atmospheric nitrogen gas, expressed in permille notation	permille	N2O
d15n_bulk_2	Second measurement of d15N bulk in N2O in reference to atmospheric nitrogen gas, expressed in permille notation	permille	d15N
d17O_2	Second measurement of d17O in N2O in reference to VSMOW, expressed in permille notation	permille	delta17O
d18O_2	Second measurement of d18O in N2O in reference to VSMOW, expressed in permille notation	permille	d18O
N2O_nM_2	Second N2O concentration measurement in nanomolar (nM)	nanomoles per liter (nM)	N2O
flag_2	Data quality control flag from SeaDataNet: https://www.seadatanet.org/Standards/Data-Quality-Control. 1 = good value; 2 = probably good value; 3 = probably bad value, 4 = bad value, 9 = missing value	unitless	q_flag
Year	Deployment year	unitless	year
Month	Deployment month (local)	unitless	month
Day	Deployment day (local)	unitless	day

Database

Contribute Data

Dataset: ETSP N2O
Deployment: AT15-61

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: ETSP N2ODeployment: AT15-61

Dataset acquisition description

Dataset Processing Description

Dataset: ETSP N2O
Deployment: AT15-61