19:I[42426,["/_next/static/immutable/chunks/1xctgzqre-wsy.js","/_next/static/immutable/chunks/06_-wz6pdtp2b.js","/_next/static/immutable/chunks/30e52g49hg40p.js","/_next/static/immutable/chunks/02yq6tul2z-oh.js","/_next/static/immutable/chunks/10bx_ec2vj7n_.js","/_next/static/immutable/chunks/33bfn03fo8xnt.js","/_next/static/immutable/chunks/0tfjf78scu61b.js","/_next/static/immutable/chunks/31xnvej4n1bi9.js"],"default"] 1a:Teac,

Inocula of 15N2-enriched water were prepared according to either of two protocols outlined by Klawonn et al. (2015).
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™ 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™ 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:

Equation 4:

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):

Equation S2:

For instance, at a temperature of 25ºC and salinity of 35 psu, the solubility coefficients of Hamme and Emerson (2004) predict a N2 concentration of 388.9 μmol 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:

= 99.2687 % Equation S3a

= 0.7299 % Equation S3b

= 0.0013 % Equation S3c

Accordingly, air-equilibrated concentrations of 28N2, 29N2, and 30N2 at this temperature and salinity are 386.0, 2.8, and 0.005 μmol 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 “incubations” was then calculated using a linear mixing model with N2 isotopologue concentrations in ambient and enriched seawater

1b:T7f4,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.6:["$","$L19",null,{"dataset":{"_id":"778126","description":"

Trial A test of the dissolution method

\n","problem":"","acquisition":"$1a","processing":"

BCO-DMO Processing Notes:
\n- table was extracted from original spreadsheet.
\n- added conventional header with dataset name, PI name, version date
\n- modified parameter names to conform with BCO-DMO naming conventions

\n","bcodmoProcessing":"","title":"Trial A test of the dissolution method for estimates of the 15N2 atom% of incubations","nickname":"trial_a","dataUrl":"","currentState":"Final no updates expected","currentStateId":"7","validated":true,"restricted":false,"version":"1","version_date":"2019-10-02T04:00:00.000Z","abstract":"The “dissolution” 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.","citation":"Granger, J., Bourbonnais, A., Wilson, S. (2019) Trial A test of the dissolution method for estimates of the 15N2 atom% of incubations. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2019-10-02 [if applicable, indicate subset used]. doi:10.1575/1912/bco-dmo.778126.1 [access date]","citationParts":{"identifier":"doi:10.1575/1912/bco-dmo.778126.1","versionDate":"2019-10-02","versionId":"1","year":"2019","title":"Trial A test of the dissolution method for estimates of the 15N2 atom% of incubations","authors":"Granger, J., Bourbonnais, A., Wilson, S.","publisher":"Biological and Chemical Oceanography Data Management Office (BCO-DMO)."},"doi":"10.1575/1912/bco-dmo.778126.1","release_date":null,"field_dataset_location":"","temporal_extent":{"start":null,"end":null},"temporal":{"resolution":"","type":"","start":{"value":"","label":""},"end":{"value":"","label":""}},"spatial_extent":{"shape":"","center":{"latitude":0,"longitude":0},"wkt":"","north":0,"east":0,"south":0,"west":0},"dataset_type":["experimental"],"keywords":["oceans"],"data_files":[{"id":"902653","title":"trial_a.csv","url":"https://datadocs.bco-dmo.org/dataset/778126/file/WWW1rw2SzppB8G/trial_a.csv","showTableUrl":"https://www.bco-dmo.org/dataset/778126/data/view/902653","description":"Primary data file for dataset ID 778126","filename":"trial_a.csv","bytesize":6309,"checksum":{"value":"2298e8da89522e950fdb4b6cf8296398","Algorithm":{"_id":"190","name":"MD5"}},"mimetype":"text/csv","fileType":{"_id":"192","name":"Comma Separated Values (.csv)"},"isErddap":"bcodmo_dataset_778126","date":"","isPublicDuringEmbargo":false,"primaryDataFile":true,"showTable":true,"restricted":false}],"supplemental_files":[{"id":"778527","title":"equation 4 EAGER_NitFix","url":"https://datadocs.bco-dmo.org/docs/302/EAGER_NitFix/data_docs/equation_4.jpg","showTableUrl":"","description":"The 15N atom % of the inocula and of the corresponding incubations were measured by MIMS at the University of Connecticut (Bay Instruments) and computed using this equation.","filename":"equation_4.jpg","bytesize":25208,"checksum":{"value":"25f19b478991407bd347bd9221c4857b","Algorithm":{"_id":"190","name":"MD5"}},"mimetype":"image/jpeg","fileType":{"_id":"415","name":"JPEG Image (.jpg)"},"isErddap":"","date":"","isPublicDuringEmbargo":false,"primaryDataFile":false,"showTable":false,"restricted":false},{"id":"778528","title":"equation S2 Eager_NitFix","url":"https://datadocs.bco-dmo.org/docs/302/EAGER_NitFix/data_docs/equation_s2.jpg","showTableUrl":"","description":"Equation for the definition of the ionization efficiency as the ratio of the isotopologue ion current measured by MIMS relative to its concentration in air-equilibrated seawater (ASW).","filename":"equation_s2.jpg","bytesize":24231,"checksum":{"value":"af88aa623a8e948669b26dbeb4dbaeaf","Algorithm":{"_id":"190","name":"MD5"}},"mimetype":"image/jpeg","fileType":{"_id":"415","name":"JPEG Image (.jpg)"},"isErddap":"","date":"","isPublicDuringEmbargo":false,"primaryDataFile":false,"showTable":false,"restricted":false},{"id":"778529","title":"equation s3a Eager_NitFix","url":"https://datadocs.bco-dmo.org/docs/302/EAGER_NitFix/data_docs/equation_s3a.jpg","showTableUrl":"","description":"Equation for the binomial probability distribution for 28N2.","filename":"equation_s3a.jpg","bytesize":9810,"checksum":{"value":"fdc41b085863b05134fbb25f6cc25c54","Algorithm":{"_id":"190","name":"MD5"}},"mimetype":"image/jpeg","fileType":{"_id":"415","name":"JPEG Image (.jpg)"},"isErddap":"","date":"","isPublicDuringEmbargo":false,"primaryDataFile":false,"showTable":false,"restricted":false},{"id":"778530","title":"equation s3b Eager_NitFix","url":"https://datadocs.bco-dmo.org/docs/302/EAGER_NitFix/data_docs/equation_s3b.jpg","showTableUrl":"","description":"Equation for the binomial probability distribution for 29N2.","filename":"equation_s3b.jpg","bytesize":22648,"checksum":{"value":"d7200880be28043d090d28bebeda9d12","Algorithm":{"_id":"190","name":"MD5"}},"mimetype":"image/jpeg","fileType":{"_id":"415","name":"JPEG Image (.jpg)"},"isErddap":"","date":"","isPublicDuringEmbargo":false,"primaryDataFile":false,"showTable":false,"restricted":false},{"id":"778531","title":"equation s3c Eager_NitFix","url":"https://datadocs.bco-dmo.org/docs/302/EAGER_NitFix/data_docs/equation_s3c.jpg","showTableUrl":"","description":"Equation for the binomial probability distribution for 30N2.","filename":"equation_s3c.jpg","bytesize":15058,"checksum":{"value":"04c7942d3273c43e9c10e3ed2b41b0fd","Algorithm":{"_id":"190","name":"MD5"}},"mimetype":"image/jpeg","fileType":{"_id":"415","name":"JPEG Image (.jpg)"},"isErddap":"","date":"","isPublicDuringEmbargo":false,"primaryDataFile":false,"showTable":false,"restricted":false}],"roles":[{"role":{"_id":"138","name":"Principal Investigator"},"performedBy":{"_id":"528937","name":"Julie Granger"},"performedAtOrganization":{"_id":"85","name":"University of Connecticut"}},{"role":{"_id":"140","name":"Co-Principal Investigator"},"performedBy":{"_id":"778011","name":"Annie Bourbonnais"},"performedAtOrganization":{"_id":"189","name":"University of Massachusetts Dartmouth"}},{"role":{"_id":"140","name":"Co-Principal Investigator"},"performedBy":{"_id":"51733","name":"Samuel T. Wilson"},"performedAtOrganization":{"_id":"62","name":"University of Hawai'i"}},{"role":{"_id":"145","name":"BCO-DMO Data Manager"},"performedBy":{"_id":"708682","name":"Mathew Biddle"},"performedAtOrganization":{"_id":"191","name":"Woods Hole Oceanographic Institution"}}],"deployments":[],"funding":[{"_id":"772538","name":"OCE-1732246","fundingSource":{"_id":"355","name":"NSF Division of Ocean Sciences"},"url":"https://www.nsf.gov/awardsearch/show-award?AWD_ID=1732246"}],"instruments":[{"_id":"778134","name":"Isotope Ratio Mass Spectrometer","description":"continuous flow Delta V Isotope Ratio Mass Spectrometer (Smith et al. 2015), and continuous flow-GV Isoprime IRMS (Charoenpong et al., 2014)","type_id":"469","type_name":"Isotope-ratio Mass Spectrometer","type_desc":"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).","type_acronym":"IR Mass Spec; IRMS"},{"_id":"778133","name":"Membrane Inlet Mass Spectrometer","description":"Membrane Inlet Mass Spectrometer (Bay Instruments)","type_id":"661606","type_name":"Membrane Inlet Mass Spectrometer","type_desc":"Membrane-introduction mass spectrometry (MIMS) is a method of introducing analytes into the mass spectrometer's vacuum chamber via a semipermeable membrane.","type_acronym":"MIMS"}],"parameters":[{"_id":"778136","name":"Sample","format":"","frictionlessType":"","description":"

sample

","units":{"_id":"","name":"unitless"},"type":{"_id":"960","name":"sample","description":"

unique sample identification or number; any combination of alpha numeric characters; precise definition is file dependent

"}},{"_id":"778137","name":"Baro_Press","format":"","frictionlessType":"","description":"

barometric pressue

","units":{"_id":"","name":"unknown"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}},{"_id":"778138","name":"Time_of_analysis","format":"","frictionlessType":"","description":"

time of analysis

","units":{"_id":"","name":"unitless"},"type":{"_id":"1075","name":"time","description":"

Time GMT defined as HHMM; time of day; generally reported in GMT as HHMM (hours and minutes) but may also be HH.H (decimal hours) or HHMMSS (hours; minutes and seconds); in EqPac time is reported as Hawaii local time

"}},{"_id":"778139","name":"m_z_28","format":"","frictionlessType":"","description":"

mass-to-charge

","units":{"_id":"","name":"unitless"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}},{"_id":"778140","name":"m_z_29","format":"","frictionlessType":"","description":"

mass-to-charge

","units":{"_id":"","name":"unitless"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}},{"_id":"778141","name":"m_z_30","format":"","frictionlessType":"","description":"

mass-to-charge

","units":{"_id":"","name":"unitless"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}},{"_id":"778142","name":"m_z_32","format":"","frictionlessType":"","description":"

mass-to-charge

","units":{"_id":"","name":"unitless"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}},{"_id":"778143","name":"m_z_40","format":"","frictionlessType":"","description":"

mass-to-charge

","units":{"_id":"","name":"unitless"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}},{"_id":"778144","name":"N2_Ar","format":"","frictionlessType":"","description":"

N2/Ar ratio

","units":{"_id":"","name":"unitless"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}},{"_id":"778145","name":"ratio_28_29","format":"","frictionlessType":"","description":"

28/29 ratio

","units":{"_id":"","name":"unitless"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}},{"_id":"778146","name":"ratio_28_30","format":"","frictionlessType":"","description":"

28/30 ratio

","units":{"_id":"","name":"unitless"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}},{"_id":"778147","name":"meas_at_pcnt","format":"","frictionlessType":"","description":"

measured atom percent

","units":{"_id":"","name":"unitless"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}},{"_id":"778148","name":"avg_measured_a_pcnt","format":"","frictionlessType":"","description":"

average measured atom percent

","units":{"_id":"","name":"unitless"},"type":{"_id":"1073","name":"no_bcodmo_term","description":"

An association with a community-wide standard parameter has not yet been made.

"}}],"related_publications":[{"id":"778020","citation":"White, A. E., Granger, J., Selden, C., Gradoville, M. R., Potts, L., Bourbonnais, A., Fulweiler, R. W., Knapp, A. N., Mohr, W., Moisander, P. H., Tobias, C. R., Caffin, M., Wilson, S. T., Benavides, M., Bonnet, S., Mulholland, M. R., & Chang, B. X. (2020). A critical review of the 15N2 tracer method to measure diazotrophic production in pelagic ecosystems. Limnology and Oceanography: Methods, 18(4), 129–147. Wiley. https://doi.org/10.1002/lom3.10353\r\n","relation_type":["Results"],"relation_desc":""}],"related_datasets":[],"services":[{"grouping":"","items":[{"name":"View Data","description":"An in-browser view of the primary tabular data file","url":"https://www.bco-dmo.org/dataset/778126/data/view","contentType":"text/html","actionType":"view"}]},{"grouping":"ERDDAP","items":[{"name":"SUBSET DATA","description":"","url":"https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_778126.html","contentType":"text/html","actionType":"tool"},{"name":"VIEW TABLE","description":"","url":"https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_778126.htmlTable","contentType":"text/html","actionType":"view"},{"name":"CSV","description":"","url":"https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_778126.csv","contentType":"text/csv","actionType":"download"},{"name":"TSV","description":"","url":"https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_778126.tsv","contentType":"text/tsv","actionType":"download"},{"name":"MATLAB","description":"","url":"https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_778126.mat","contentType":"text/x-matlab","actionType":"download"},{"name":"netCDF","description":"","url":"https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_778126.nc","contentType":"application/x-netcdf","actionType":"download"}]},{"grouping":"Metadata","items":[{"name":"HTML","description":"A simple HTML page of the dataset metadata","url":"https://www.bco-dmo.org/dataset/778126/description","contentType":"text/html","actionType":"view"},{"name":"PDF","description":"A PDF of the HTML dataset metadata","url":"https://www.bco-dmo.org/dataset/778126/Dataset_description.pdf","contentType":"application/pdf","actionType":"download"},{"name":"ISO 19115-2 (NOAA Profile)","description":"","url":"https://www.bco-dmo.org/dataset/778126/iso","contentType":"application/xml","actionType":"download"}]}],"programs":[],"projects":[{"_id":"772534","name":"EAGER: Collaborative Research: Detection limit in marine nitrogen fixation measurements - Constraints of rates from the mesopelagic ocean","acronym":"EAGER NitFix","description":"$1b"}],"archives":[{"id_value":"10.1575/1912/bco-dmo.778126.1","url":"https://doi.org/10.1575/1912/bco-dmo.778126.1","date_assigned":"2020-01-06","version_date":"2019-10-02","archiver":"Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)","archiver_id":"272"}],"license":{"name":"Creative Commons Attribution 4.0","id":"CC-BY-4.0","uri":"https://creativecommons.org/licenses/by/4.0/","spdxUri":"https://spdx.org/licenses/CC-BY-4.0"},"metrics":{"views":{"count":112},"downloads":{"count":2433}}}}]