ERDDAP > info > bcodmo_dataset_778126

Grid DAP Data	Sub- set	Table DAP Data	Make A Graph	W M S	Source Data Files	Acces- sible	Title	Sum- mary	FGDC, ISO, Metadata	Back- ground Info	RSS	E mail	Institution	Dataset ID
		data	graph		files	public	[trial_a] - Trial A test of the dissolution method for estimates of the 15N2 atom% of incubations (EAGER: Collaborative Research: Detection limit in marine nitrogen fixation measurements - Constraints of rates from the mesopelagic ocean)		I   M	background			BCO-DMO	bcodmo_dataset_778126

The Dataset's Variables and Attributes

Row Type	Variable Name	Attribute Name	Data Type	Value
attribute	NC_GLOBAL	access_formats	String	.htmlTable,.csv,.json,.mat,.nc,.tsv
attribute	NC_GLOBAL	acquisition_description	String	Inocula of 15N2-enriched water were prepared according to either of two protocols outlined by Klawonn et al. (2015).\u00a0 In a first Trial A, respective 1.9 mL of 15N2 gas aliquots (Cambridge Isotope Laboratories, Lot #I-21065) were injected into crimped-sealed 120 mL glass serum vials filled with deionized water. To dissolve the 15N2 bubble, each of the two serum vials was vortexed for 5 minutes. Two subsamples of each inoculum were dispensed into Exetainers\u2122 with a peristaltic pump for analysis on the MIMS. An aliquot of each inoculum (5 % vol/vol) was then dispensed in replicate 160 mL serum incubation bottles containing air- equilibrated deionized water (Trials A1-A4), which were then crimped-sealed. Following homogenization, triplicate subsamples of each incubation were collected in Exetainers\u2122 for MIMS analysis. The 15N atom % of the inocula and of the corresponding incubations were measured by MIMS at the University of Connecticut (Bay Instruments) and computed as follows:\u00a0 Equation 4:\u00a0 In both trials, the concentration of N2 isotopologues (m/z 28, 29, and 30) in each of the 15N2-enriched inocula was then extrapolated from the ionization efficiency of N isotopologues in air-equilibrated seawater. We define the ionization efficiency as the ratio of the isotopologue ion current measured by MIMS relative to its concentration in air-equilibrated seawater (ASW):\u00a0 \u00a0 Equation S2:\u00a0 For instance, at a temperature of 25\u00baC and salinity of 35 psu, the solubility coefficients of Hamme and Emerson (2004) predict a N2 concentration of 388.9 \u03bcmol kg-1. The fraction of 15N in N2 (i.e., 15N/(14N+15N)) for air-equilibrated seawater is 0.003663 (Mariotti, 1983), such that the expected fractions of 28N2, 29N2, and 30N2 derived from their binomial probability distributions are as follows: \u00a0 \u00a0 = 99.2687 % Equation S3a = 0.7299 % Equation S3b = 0.0013 % Equation S3c \u00a0 Accordingly, air-equilibrated concentrations of 28N2, 29N2, and 30N2 at this temperature and salinity are 386.0, 2.8, and 0.005 \u03bcmol kg-1, respectively. The ionization efficiency of the isotopologues is then equal to the ion current of m/z 28 recorded for ASW divided by the corresponding 28N2 concentration (Eq. S2). We used the ionization efficiency of m/z 28 in ASW to derive the N2 isotopologue concentrations in the inocula from their respective MIMS ion currents. We did not derive distinct ionization efficiencies from the ion current-to-concentration of m/z 29 and 30 in ASW, as these isotopologues are poorly resolved by the MIMS at natural abundance. Thus, we are assuming that the ionization efficiency of m/z 29 and 30 isotopologues is roughly similar to that of m/z 28 (i.e., that ionization isotope effects are negligible for our purposes). The initial expected AN2 of the \u201cincubations\u201d was then calculated using a linear mixing model with N2 isotopologue concentrations in ambient and enriched seawater
attribute	NC_GLOBAL	awards_0_award_nid	String	772538
attribute	NC_GLOBAL	awards_0_award_number	String	OCE-1732246
attribute	NC_GLOBAL	awards_0_data_url	String	http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1732246
attribute	NC_GLOBAL	awards_0_funder_name	String	NSF Division of Ocean Sciences
attribute	NC_GLOBAL	awards_0_funding_acronym	String	NSF OCE
attribute	NC_GLOBAL	awards_0_funding_source_nid	String	355
attribute	NC_GLOBAL	awards_0_program_manager	String	Henrietta N Edmonds
attribute	NC_GLOBAL	awards_0_program_manager_nid	String	51517
attribute	NC_GLOBAL	cdm_data_type	String	Other
attribute	NC_GLOBAL	comment	String	Trial A test of the dissolution method PI: Julie Granger Version: 2019-09-30
attribute	NC_GLOBAL	Conventions	String	COARDS, CF-1.6, ACDD-1.3
attribute	NC_GLOBAL	creator_email	String	info at bco-dmo.org
attribute	NC_GLOBAL	creator_name	String	BCO-DMO
attribute	NC_GLOBAL	creator_type	String	institution
attribute	NC_GLOBAL	creator_url	String	https://www.bco-dmo.org/
attribute	NC_GLOBAL	data_source	String	extract_data_as_tsv version 2.3 19 Dec 2019
attribute	NC_GLOBAL	date_created	String	2019-09-30T19:01:20Z
attribute	NC_GLOBAL	date_modified	String	2019-10-02T18:51:48Z
attribute	NC_GLOBAL	defaultDataQuery	String	&time<now
attribute	NC_GLOBAL	doi	String	10.1575/1912/bco-dmo.778126.1
attribute	NC_GLOBAL	infoUrl	String	https://www.bco-dmo.org/dataset/778126
attribute	NC_GLOBAL	institution	String	BCO-DMO
attribute	NC_GLOBAL	instruments_0_acronym	String	IR Mass Spec
attribute	NC_GLOBAL	instruments_0_dataset_instrument_description	String	continuous flow Delta V Isotope Ratio Mass Spectrometer (Smith et al. 2015), and continuous flow-GV Isoprime IRMS (Charoenpong et al., 2014)
attribute	NC_GLOBAL	instruments_0_dataset_instrument_nid	String	778134
attribute	NC_GLOBAL	instruments_0_description	String	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).
attribute	NC_GLOBAL	instruments_0_instrument_external_identifier	String	https://vocab.nerc.ac.uk/collection/L05/current/LAB16/
attribute	NC_GLOBAL	instruments_0_instrument_name	String	Isotope-ratio Mass Spectrometer
attribute	NC_GLOBAL	instruments_0_instrument_nid	String	469
attribute	NC_GLOBAL	instruments_0_supplied_name	String	Isotope Ratio Mass Spectrometer
attribute	NC_GLOBAL	instruments_1_acronym	String	MIMS
attribute	NC_GLOBAL	instruments_1_dataset_instrument_description	String	Membrane Inlet Mass Spectrometer (Bay Instruments)
attribute	NC_GLOBAL	instruments_1_dataset_instrument_nid	String	778133
attribute	NC_GLOBAL	instruments_1_description	String	Membrane-introduction mass spectrometry (MIMS) is a method of introducing analytes into the mass spectrometer's vacuum chamber via a semipermeable membrane.
attribute	NC_GLOBAL	instruments_1_instrument_name	String	Membrane Inlet Mass Spectrometer
attribute	NC_GLOBAL	instruments_1_instrument_nid	String	661606
attribute	NC_GLOBAL	instruments_1_supplied_name	String	Membrane Inlet Mass Spectrometer
attribute	NC_GLOBAL	keywords	String	analysis, average, avg_measured_a_pcnt, baro, Baro_Press, bco, bco-dmo, biological, chemical, data, dataset, dmo, erddap, m_z_28, m_z_29, m_z_30, m_z_32, m_z_40, management, meas, meas_at_pcnt, measured, N2_Ar, oceanography, office, pcnt, preliminary, press, ratio, ratio_28_29, ratio_28_30, sample, time, Time_of_analysis
attribute	NC_GLOBAL	license	String	https://www.bco-dmo.org/dataset/778126/license
attribute	NC_GLOBAL	metadata_source	String	https://www.bco-dmo.org/api/dataset/778126
attribute	NC_GLOBAL	param_mapping	String	{'778126': {}}
attribute	NC_GLOBAL	parameter_source	String	https://www.bco-dmo.org/mapserver/dataset/778126/parameters
attribute	NC_GLOBAL	people_0_affiliation	String	University of Connecticut
attribute	NC_GLOBAL	people_0_affiliation_acronym	String	UConn
attribute	NC_GLOBAL	people_0_person_name	String	Julie Granger
attribute	NC_GLOBAL	people_0_person_nid	String	528937
attribute	NC_GLOBAL	people_0_role	String	Principal Investigator
attribute	NC_GLOBAL	people_0_role_type	String	originator
attribute	NC_GLOBAL	people_1_affiliation	String	University of Massachusetts Dartmouth
attribute	NC_GLOBAL	people_1_affiliation_acronym	String	UMass Dartmouth
attribute	NC_GLOBAL	people_1_person_name	String	Annie Bourbonnais
attribute	NC_GLOBAL	people_1_person_nid	String	778011
attribute	NC_GLOBAL	people_1_role	String	Co-Principal Investigator
attribute	NC_GLOBAL	people_1_role_type	String	originator
attribute	NC_GLOBAL	people_2_affiliation	String	University of Hawaii
attribute	NC_GLOBAL	people_2_person_name	String	Samuel Wilson
attribute	NC_GLOBAL	people_2_person_nid	String	51733
attribute	NC_GLOBAL	people_2_role	String	Co-Principal Investigator
attribute	NC_GLOBAL	people_2_role_type	String	originator
attribute	NC_GLOBAL	people_3_affiliation	String	Woods Hole Oceanographic Institution
attribute	NC_GLOBAL	people_3_affiliation_acronym	String	WHOI BCO-DMO
attribute	NC_GLOBAL	people_3_person_name	String	Mathew Biddle
attribute	NC_GLOBAL	people_3_person_nid	String	708682
attribute	NC_GLOBAL	people_3_role	String	BCO-DMO Data Manager
attribute	NC_GLOBAL	people_3_role_type	String	related
attribute	NC_GLOBAL	project	String	EAGER NitFix
attribute	NC_GLOBAL	projects_0_acronym	String	EAGER NitFix
attribute	NC_GLOBAL	projects_0_description	String	NSF Award Abstract: The availability of nitrogen is required to support the growth and production of organisms living in the surface of our global ocean. This element can be scarce. To alleviate this scarcity, a special class of bacteria and archaea, called nitrogen fixers, can derive the nitrogen needed for growth from nitrogen gas. This project would carefully examine one specific method for measuring nitrogen fixation that has been used recently to suggest the occurrence of small amounts of nitrogen fixation in subsurface ocean waters. If these reports are verified, then a revision of our understanding of the marine nitrogen cycle may be needed. The Ocean Carbon and Biogeochemistry program will be used as a platform to develop community consensus for best practices in nitrogen fixation measurements and detection of diversity, activity, and abundances of the organisms responsible. In addition, a session will be organized in a future national/international conference to communicate with the broader scientific community while developing these best practices. The goal of this study is to conduct a thorough examination of potential experimental and analytical errors inherent to the 15N2-tracer nitrogen fixation method, in tandem with comprehensive molecular measurements, in mesopelagic ocean waters. Samples will be collected and experimental work conducted on a cruise transect in the North Atlantic Ocean, followed by analytical work in the laboratory. The specific aims of this study are to (1) determine the minimum quantifiable rates of 15N2 fixation based on incubations of mesopelagic waters via characterization of sources of experimental and analytical error, and (2) seek evidence of presence and expression of nitrogen fixation genes via comprehensive molecular approaches on corresponding samples. The range of detectable rates and diazotroph activity from the measurements made in this study will be informative for the understanding of the importance of nitrogen fixation in the oceanic nitrogen budget.
attribute	NC_GLOBAL	projects_0_end_date	String	2018-10
attribute	NC_GLOBAL	projects_0_geolocation	String	North Atlantic Ocean, Pacific Ocean
attribute	NC_GLOBAL	projects_0_name	String	EAGER: Collaborative Research: Detection limit in marine nitrogen fixation measurements - Constraints of rates from the mesopelagic ocean
attribute	NC_GLOBAL	projects_0_project_nid	String	772534
attribute	NC_GLOBAL	projects_0_start_date	String	2017-05
attribute	NC_GLOBAL	publisher_name	String	Biological and Chemical Oceanographic Data Management Office (BCO-DMO)
attribute	NC_GLOBAL	publisher_type	String	institution
attribute	NC_GLOBAL	sourceUrl	String	(local files)
attribute	NC_GLOBAL	standard_name_vocabulary	String	CF Standard Name Table v55
attribute	NC_GLOBAL	summary	String	The \u201cdissolution\u201d method to measure N2 fixation rates with 15N2 gas tracer involves the preparation of 15N2-enriched water that is then added to each incubation bottle. Investigators typically measure the 15N2 atom% of the 15N2-enriched inoculum by MIMS, and extrapolate the 15N2 atom% in the incubations based on the inoculum value. Here, we demonstrate that such extrapolation yields inaccurate estimates of the 15N2 atom% of incubations. The latter should be measured directly.
attribute	NC_GLOBAL	title	String	[trial_a] - Trial A test of the dissolution method for estimates of the 15N2 atom% of incubations (EAGER: Collaborative Research: Detection limit in marine nitrogen fixation measurements - Constraints of rates from the mesopelagic ocean)
attribute	NC_GLOBAL	version	String	1
attribute	NC_GLOBAL	xml_source	String	osprey2erddap.update_xml() v1.3
variable	Sample		String
attribute	Sample	bcodmo_name	String	sample
attribute	Sample	description	String	sample
attribute	Sample	long_name	String	Sample
attribute	Sample	nerc_identifier	String	https://vocab.nerc.ac.uk/collection/P02/current/ACYC/
attribute	Sample	units	String	unitless
variable	Baro_Press		float
attribute	Baro_Press	_FillValue	float	NaN
attribute	Baro_Press	actual_range	float	30.51, 30.53
attribute	Baro_Press	bcodmo_name	String	unknown
attribute	Baro_Press	description	String	barometric pressue
attribute	Baro_Press	long_name	String	Baro Press
attribute	Baro_Press	units	String	unknown
variable	Time_of_analysis		String
attribute	Time_of_analysis	bcodmo_name	String	time
attribute	Time_of_analysis	description	String	time of analysis
attribute	Time_of_analysis	long_name	String	Time Of Analysis
attribute	Time_of_analysis	nerc_identifier	String	https://vocab.nerc.ac.uk/collection/P01/current/AHMSAA01/
attribute	Time_of_analysis	units	String	unitless
variable	m_z_28		double
attribute	m_z_28	_FillValue	double	NaN
attribute	m_z_28	actual_range	double	1.946714E-8, 0.16527391698923202
attribute	m_z_28	bcodmo_name	String	unknown
attribute	m_z_28	description	String	mass-to-charge
attribute	m_z_28	long_name	String	M Z 28
attribute	m_z_28	units	String	unitless
variable	m_z_29		double
attribute	m_z_29	_FillValue	double	NaN
attribute	m_z_29	actual_range	double	1.591554E-10, 0.13304737362866276
attribute	m_z_29	bcodmo_name	String	unknown
attribute	m_z_29	description	String	mass-to-charge
attribute	m_z_29	long_name	String	M Z 29
attribute	m_z_29	units	String	unitless
variable	m_z_30		double
attribute	m_z_30	_FillValue	double	NaN
attribute	m_z_30	actual_range	double	3.340442E-12, 3.080166212540741
attribute	m_z_30	bcodmo_name	String	unknown
attribute	m_z_30	description	String	mass-to-charge
attribute	m_z_30	long_name	String	M Z 30
attribute	m_z_30	units	String	unitless
variable	m_z_32		double
attribute	m_z_32	_FillValue	double	NaN
attribute	m_z_32	actual_range	double	1.735591E-11, 1.062805216597332
attribute	m_z_32	bcodmo_name	String	unknown
attribute	m_z_32	description	String	mass-to-charge
attribute	m_z_32	long_name	String	M Z 32
attribute	m_z_32	units	String	unitless
variable	m_z_40		double
attribute	m_z_40	_FillValue	double	NaN
attribute	m_z_40	actual_range	double	5.645087E-10, 1.1222807152753036
attribute	m_z_40	bcodmo_name	String	unknown
attribute	m_z_40	description	String	mass-to-charge
attribute	m_z_40	long_name	String	M Z 40
attribute	m_z_40	units	String	unitless
variable	N2_Ar		float
attribute	N2_Ar	_FillValue	float	NaN
attribute	N2_Ar	actual_range	float	33.95307, 39.72807
attribute	N2_Ar	bcodmo_name	String	unknown
attribute	N2_Ar	description	String	N2/Ar ratio
attribute	N2_Ar	long_name	String	N2 Ar
attribute	N2_Ar	units	String	unitless
variable	ratio_28_29		float
attribute	ratio_28_29	_FillValue	float	NaN
attribute	ratio_28_29	actual_range	float	120.9205, 135.7853
attribute	ratio_28_29	bcodmo_name	String	unknown
attribute	ratio_28_29	description	String	28/29 ratio
attribute	ratio_28_29	long_name	String	Ratio 28 29
attribute	ratio_28_29	units	String	unitless
variable	ratio_28_30		float
attribute	ratio_28_30	_FillValue	float	NaN
attribute	ratio_28_30	actual_range	float	1.430992, 10582.37
attribute	ratio_28_30	bcodmo_name	String	unknown
attribute	ratio_28_30	description	String	28/30 ratio
attribute	ratio_28_30	long_name	String	Ratio 28 30
attribute	ratio_28_30	units	String	unitless
variable	meas_at_pcnt		double
attribute	meas_at_pcnt	_FillValue	double	NaN
attribute	meas_at_pcnt	actual_range	double	0.3756647104406213, 41.17840652185543
attribute	meas_at_pcnt	bcodmo_name	String	unknown
attribute	meas_at_pcnt	description	String	measured atom percent
attribute	meas_at_pcnt	long_name	String	Meas At Pcnt
attribute	meas_at_pcnt	units	String	unitless
variable	avg_measured_a_pcnt		float
attribute	avg_measured_a_pcnt	_FillValue	float	NaN
attribute	avg_measured_a_pcnt	actual_range	float	0.38, 41.11
attribute	avg_measured_a_pcnt	bcodmo_name	String	unknown
attribute	avg_measured_a_pcnt	description	String	average measured atom percent
attribute	avg_measured_a_pcnt	long_name	String	Avg Measured A Pcnt
attribute	avg_measured_a_pcnt	units	String	unitless

The information in the table above is also available in other file formats (.csv, .htmlTable, .itx, .json, .jsonlCSV1, .jsonlCSV, .jsonlKVP, .mat, .nc, .nccsv, .tsv, .xhtml) via a RESTful web service.