http://lod.bco-dmo.org/id/dataset/928568
eng; USA
utf8
dataset
Highest level of data collection, from a common set of sensors or instrumentation, usually within the same research project
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
2024-05-23
ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data
ISO 19115-2:2009(E)
Nitrogen fixation incubation data from cruise TN368 in July 2019 for SPIROPA project
2024-05-23
publication
2024-05-23
revision
BCO-DMO Linked Data URI
2024-05-23
creation
http://lod.bco-dmo.org/id/dataset/928568
Margaret Mulholland
Old Dominion University
principalInvestigator
Phoebe Dreux Chappell
Old Dominion University
principalInvestigator
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
publisher
Cite this dataset as: Mulholland, M., Chappell, P. D. (2024) Nitrogen fixation incubation data from cruise TN368 in July 2019 for SPIROPA project. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2024-05-23 [if applicable, indicate subset used]. http://lod.bco-dmo.org/id/dataset/928568 [access date]
after Selden et al. 2024 JGR Table S1 Dataset Description: <p>This nitrogen fixation incubation data&nbsp;is a supplement to BCO-DMO dataset&nbsp;https://www.bco-dmo.org/dataset/927927, which is&nbsp;hydrographic, nutrient, and mean nitrogen fixation rate data from the SPIROPA project's third cruise.&nbsp; Bottle data from the TN368 cruise (Chief Sci McGillicuddy) can be viewed here:&nbsp;https://www.bco-dmo.org/dataset/849340.</p>
<p><strong>Glossary of terms:</strong><br />
A = Atom-% enrichment<br />
APN = Atom-% enrichment of the particulate nitrogen pool<br />
BDL = Below detection limit<br />
DNQ = Detectable but not quantifiable<br />
LOD = Limit of detection<br />
LOQ = Limit of quantification<br />
N2 = Nitrogen gas<br />
PETG = Polyethylene Terephthalate Glycol<br />
PN = Particulate nitrogen<br />
NFR = Nitrogen fixation rate<br />
SUR = Specific uptake rate<br />
t0 = time initial<br />
tf = time final</p> Methods and Sampling: <div class="field" id="form_location">
<p>Nitrogen fixation rates and hydrographic data were measured in July 2019 in&nbsp;conjunction with the SPIROPA (Shelfbreak Productivity Interdisciplinary Research Operation at the Pioneer Array)&nbsp;project cruises (Chief Scientist Dr. Dennis McGillicuddy).&nbsp;This case study was conducted at the Mid-Atlantic Bight shelfbreak front to the south of Massachusetts, USA to examine whether significant N2 fixation occurs in the continental shelf region. On July 5th, 2019, the&nbsp;vessel R/V Thomas G. Thompson (cruise TN368) departed Woods Hole, MA and performed multiple transects in the&nbsp;area of 70 to 71 degrees West longitude and 39 to 40.5 degrees North latitude. Sampling was restricted to waters above the 0.1% light level.&nbsp;</p>
<p>Water was collected in 10L Niskin bottles on a 24-bottle rosette.&nbsp;Vertical conductivity, temperature, and depth profiles were measured&nbsp;concurrently using a Sea-Bird 911+ CTD profiler. Samples to determine nitrate, phosphate, and silicate concentrations were filtered (0.4 um, polycarbonate) directly from the Niskin bottles into acid-washed polyethylene bottles and stored&nbsp;frozen until analysis via standard colorimetric methods at the WHOI Nutrient Analytical Facility using a SEAL Analytical AA3 HR discrete chemistry analyzer. Detection limits for nitrate, phosphate, and silicate methods were 0.040, 0.030 and 0.009 μM, respectively.</p>
<div>
<p>This dataset presents the full incubation result&nbsp;with all replicates. The associated environmental (hydrographic) data is presented in a separate dataset&nbsp;along with the mean uptake and fixation rates. Please refer to BCO-DMO dataset&nbsp;https://www.bco-dmo.org/dataset/927927</p>
</div>
<p>Nitrogen fixation rate measurements (NFR) were quantified on repeat cross-frontal transects using the&nbsp;<sup>15</sup>N<sub>2</sub>&nbsp;bubble release technique (Chang et al., 2019; Klawonn et al., 2015), which is a variant of the <sup>15</sup>N<sub>2</sub> tracer method (Montoya et al., 1996) which accounts for the slow dissolution time of N<sub>2</sub> gas (White et al., 2020).&nbsp; The particular approach used for this study have been described in Selden et al. (2019), Selden, Chappell, et al. (2021), and Selden, Mulholland, et al. (2021). To measure&nbsp;<sup>15</sup>N<sub>2</sub>&nbsp;uptake, triplicate PETG bottles (0.5-2 L) were rinsed with whole water then filled, ensuring that no bubbles remained. Using a gas tight syringe (VICI Precision Sampling),&nbsp;<sup>15</sup>N<sub>2</sub>&nbsp;gas (~99%, Cambridge Isotope Laboratories) was added through a flexible silicon septa. Samples were gently rocked for 15 min as described by Selden et al. (2019). Any remaining bubble was subsequently removed to ensure constant isotopic enrichment over the incubation period, and bottles were incubated on-deck for approximately 24 hours. As the vessel moved across the front, a large temperature gradient was encountered (from 16°C&nbsp;to 26°C).&nbsp;To avoid temperature-shocking the samples during transit, we maintained three on-deck incubators that recirculated water through aquaria chillers (MC-1/10HP, AquaEuroUSA) housed in custom casings (built from King Starboard plastic sheet) for protection and maintained approximate temperature conditions for shelf, frontal, and offshore waters, respectively.</p>
<p>At the end of the incubation period, a 6 milliliter sample aliquot was collected from each bottle and transferred to a helium-purged Exetainer<sup>TM</sup>&nbsp;containing 50 μl zinc chloride (50% w/v). These samples were stored at room temperature and upside-down in 15 ml Falcon<sup>TM</sup>&nbsp;tubes, submerged in ultrapure water, until analysis at the UC Davis Stable Isotope Facility. The remaining incubation volume was then filtered for initial particulate nitrogen (PN) samples. Initial and final PN isotopic composition and concentration were analyzed at Old Dominion University on a Europa 20/20 isotope ratio mass spectrometer with an automated N and carbon preparation module. Low mass samples (&lt;10 µg N) were excluded from downstream analysis as IRMS response can become non-linear at low mass (White et al., 2020).</p>
<p>S<span style="color:rgb(0, 0, 0); font-family:helvetica,arial,sans-serif; font-size:14.4px">pecific uptake rates were calculated following Montoya et al. (1996), with equations detailed below.</span></p>
</div>
Funding provided by NSF Division of Ocean Sciences (NSF OCE) Award Number: OCE-1657803 Award URL: https://www.nsf.gov/awardsearch/show-award?AWD_ID=1657803
onGoing
Margaret Mulholland
Old Dominion University
757-739-0449
Department of Ocean, Earth, and Atmospheric Sciences 4600 Elkhorn Ave.
Norfolk
VA
23529-0276
USA
mmulholl@odu.edu
pointOfContact
Phoebe Dreux Chappell
Old Dominion University
USF St. Petersburg campus 140 7th Ave. South
St. Petersburg
FL
33701
USA
dreux@usf.edu
pointOfContact
asNeeded
Dataset Version: 1
Unknown
spl_id
collection_date_EST
latitude
longitude
cruise
cast
z_m
time_hr
vol_L
apn_tf
pn_uM_tf
pnpc_flag
apn_t0
pn_uM_t0
an2_flag
an2
mindetdiff
apn_t0_flag
mass_flag
pn_uM_used
sur
nfr
lod
loq
lod_sur
loq_sur
det_flag
ISO_DateTime_UTC_if_EST
ISO_DateTime_UTC_if_EDT
AquaEuroUSA Aquaria chillers (MC-1/10HP)
incubator
Europa 20/20 isotope ratio mass spectrometer with automated nitrogen and carbon preparation module
Niskin bottle
theme
None, User defined
sample identification
Date and time
latitude
longitude
Cruise identfier
cast
depth
incubation time or duration
volume
percent composition
Nitrogen
flag
No BCO-DMO term
nitrogen fixation rate
ISO_DateTime_UTC
featureType
BCO-DMO Standard Parameters
Aquarium chiller
Incubator
Isotope-ratio Mass Spectrometer
Niskin bottle
instrument
BCO-DMO Standard Instruments
TN368
service
Deployment Activity
New England Shelfbreak
place
Locations
otherRestrictions
otherRestrictions
Access Constraints: none. Use Constraints: Please follow guidelines at: http://www.bco-dmo.org/terms-use Distribution liability: Under no circumstances shall BCO-DMO be liable for any direct, incidental, special, consequential, indirect, or punitive damages that result from the use of, or the inability to use, the materials in this data submission. If you are dissatisfied with any materials in this data submission your sole and exclusive remedy is to discontinue use.
Collaborative Research: Shelfbreak Frontal Dynamics: Mechanisms of Upwelling, Net Community Production, and Ecological Implications
http://science.whoi.edu/users/olga/SPIROPA/SPIROPA.html
Collaborative Research: Shelfbreak Frontal Dynamics: Mechanisms of Upwelling, Net Community Production, and Ecological Implications
<p>NSF award abstract:</p>
<p>The continental shelf break of the Middle Atlantic Bight supports a productive and diverse ecosystem. Current paradigms suggest that this productivity is driven by several upwelling mechanisms at the shelf break front. This upwelling supplies nutrients that stimulate primary production by phytoplankton, which in turn leads to enhanced production at higher trophic levels. Although local enhancement of phytoplankton biomass has been observed in some circumstances, such a feature is curiously absent from time-averaged measurements, both from satellites and shipboard sampling. Why would there not be a mean enhancement in phytoplankton biomass as a result of the upwelling? One hypothesis is that grazing by zooplankton prevents accumulation of biomass on seasonal and longer time scales, transferring the excess production to higher trophic levels and thereby contributing to the overall productivity of the ecosystem. However, another possibility is that the net impact of these highly intermittent processes is not adequately represented in long-term means of the observations, because of the relatively low resolution of the in-water measurements and the fact that the frontal enhancement can take place below the depth observable by satellite. The deployment of the Ocean Observatories Initiative (OOI) Pioneer Array south of New England has provided a unique opportunity to test these hypotheses. The combination of moored instrumentation and autonomous underwater vehicles will facilitate observations of the frontal system with unprecedented spatial and temporal resolution. This will provide an ideal four-dimensional (space-time) context in which to conduct a detailed study of frontal dynamics and plankton communities needed to examine mechanisms controlling phytoplankton populations in this frontal system. This project will also: (1) promote teaching, training and learning via participation of graduate and undergraduate students in the research , (2) provide a broad dissemination of information by means of outreach in public forums, printed media, and a video documentary of the field work, and (3) contribute to improving societal well-being and increased economic competitiveness by providing the knowledge needed for science-based stewardship of coastal ecosystems, with particular emphasis on connecting with the fishing industry through the Commercial Fisheries Research Foundation.</p>
<p>The investigators will conduct a set of three cruises to obtain cross-shelf sections of physical, chemical, and biological properties within the Pioneer Array. Nutrient distributions will be assayed together with hydrography to detect the signature of frontal upwelling and associated nutrient supply. The investigators expect that enhanced nutrient supply will lead to changes in the phytoplankton assemblage, which will be quantified with conventional flow cytometry, imaging flow cytometry (Imaging FlowCytobot, IFCB), optical imaging (Video Plankton Recorder, VPR), traditional microscopic methods, and pigment analysis. Zooplankton will be measured in size classes ranging from micro- to mesozooplankton with the IFCB and VPR, respectively, and also with microscopic analysis. Biological responses to upwelling will be assessed by measuring rates of primary productivity, zooplankton grazing, and net community production. These observations will be synthesized in the context of a coupled physical-biological model to test the two hypotheses that can potentially explain prior observations: (1) grazer-mediated control and (2) undersampling. Hindcast simulations will also be used to diagnose the relative importance of the various mechanisms of upwelling. The intellectual merit of this effort stems from our interdisciplinary approach, advanced observational techniques, and integrated analysis in the context of a state-of-the-art coupled model. The project will address longstanding questions regarding hydrodynamics and productivity of an important ecosystem, leading to improved understanding of physical-biological interactions in a complex continental shelf regime. Given the importance of frontal systems in the global coastal ocean, it is expected that knowledge gained will have broad applicability beyond the specific region being studied.</p>
SPIROPA
largerWorkCitation
project
eng; USA
oceans
New England Shelfbreak
-71
-70
39
40.5
2019-07-05
2019-07-18
Shelf break south of New England, OOI Pioneer Array
0
BCO-DMO catalogue of parameters from Nitrogen fixation incubation data from cruise TN368 in July 2019 for SPIROPA project
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
http://lod.bco-dmo.org/id/dataset-parameter/929505.rdf
Name: spl_id
Units: dimensionless
Description: <p>Unique identifier for individual N2 uptake incubation bottles; meant for internal lab use (may be of value to anyone who wishes to discuss specific samples with corresponding authors)</p>
http://lod.bco-dmo.org/id/dataset-parameter/929506.rdf
Name: collection_date_EST
Units: dimensionless
Description: <p>Datetime of sample collection in eastern standard time (EST)</p>
http://lod.bco-dmo.org/id/dataset-parameter/929507.rdf
Name: latitude
Units: decimal degrees
Description: <p>Latitude of sampling site</p>
http://lod.bco-dmo.org/id/dataset-parameter/929508.rdf
Name: longitude
Units: decimal degrees
Description: <p>Longitude of sampling site</p>
http://lod.bco-dmo.org/id/dataset-parameter/929509.rdf
Name: cruise
Units: dimensionless
Description: <p>Cruise identification</p>
http://lod.bco-dmo.org/id/dataset-parameter/929510.rdf
Name: cast
Units: dimensionless
Description: <p>Cast identifier for cruise TN368 on R/V T.G. Thompson</p>
http://lod.bco-dmo.org/id/dataset-parameter/929511.rdf
Name: z_m
Units: meters (m)
Description: <p>Depth of sample collection</p>
http://lod.bco-dmo.org/id/dataset-parameter/929512.rdf
Name: time_hr
Units: hours
Description: <p>Duration of incubation</p>
http://lod.bco-dmo.org/id/dataset-parameter/929513.rdf
Name: vol_L
Units: liters (L)
Description: <p>Incubation volume</p>
http://lod.bco-dmo.org/id/dataset-parameter/929514.rdf
Name: apn_tf
Units: atom percent
Description: <p>Atom% 15N enrichment at final time point (i.e., at time equals incubation duration)</p>
http://lod.bco-dmo.org/id/dataset-parameter/929515.rdf
Name: pn_uM_tf
Units: micromoles nitrogen per liter (umol N2/L)
Description: <p>Particulate nitrogen concentration at final time point</p>
http://lod.bco-dmo.org/id/dataset-parameter/929516.rdf
Name: pnpc_flag
Units: dimensionless
Description: <p>Flag indicating whether an independent sample was available to determine particulate nitrogen concentration at the time of sample collection; "NO_SPL" indicates that no sample was available; "INSUFFICIENT_N_MASS" indicates that the sample collected for initial PN determination did not have sufficient mass (>10 ug N) to allow for robust isotopic analysis</p>
http://lod.bco-dmo.org/id/dataset-parameter/929517.rdf
Name: apn_t0
Units: atom percent
Description: <p>Atom% 15N enrichment at initial time point</p>
http://lod.bco-dmo.org/id/dataset-parameter/929518.rdf
Name: pn_uM_t0
Units: micromoles nitrogen per liter (umol N2/L)
Description: <p>Particulate nitrogen concentration at initial time point</p>
http://lod.bco-dmo.org/id/dataset-parameter/929519.rdf
Name: an2_flag
Units: dimensionless
Description: <p>Flag indicating whether a subsample to directly determine 15N enrichment of the N2 pool in the specific incubation bottle was analyzed; "NO_AN2_SPL_RUN" indicates that the sample was lost, damaged, or otherwise unable to be analyzed</p>
http://lod.bco-dmo.org/id/dataset-parameter/929520.rdf
Name: an2
Units: atom percent
Description: <p>Atom% 15N enrichment of N2 pool in incubation bottle; subsampled at final time point</p>
http://lod.bco-dmo.org/id/dataset-parameter/929521.rdf
Name: mindetdiff
Units: atom percent
Description: <p>The minimum detectable difference between the atom% enrichment at the initial and final time points of the incubation; calculated as 3 times the standard deviation of 7 replicate 12.5 ug N standards (sulfanilimide)</p>
http://lod.bco-dmo.org/id/dataset-parameter/929522.rdf
Name: apn_t0_flag
Units: dimensionless
Description: <p>Flag indicates where the atom% 15N enrichment of the N2 pool came from; "MEAN_APNT0_USED_IN_CALC" indicates that the mean atom% enrichment achieved across experiments was used to calculate a rate; no flag indicates that a direct measurement was available and used</p>
http://lod.bco-dmo.org/id/dataset-parameter/929523.rdf
Name: mass_flag
Units: dimensionless
Description: <p>Flag indicates where the particulate nitrogen concentration used to calculate a N2 fixation rate came from; "Tf_MASS_USED" indicates that no data was available for the initial time point to calculate an average across the incubation, and concentration was instead assumed constant across the incubation (and the final time point concentration value was used); no value indicates that the average across the incubation period was used</p>
http://lod.bco-dmo.org/id/dataset-parameter/929524.rdf
Name: pn_uM_used
Units: micromoles nitrogen per liter (umol N2/L/day)
Description: <p>The actual value for particulate nitrogen concentration used to calculate N2 fixation rate; where concentrations were available at both initial and final time points, the average was used</p>
http://lod.bco-dmo.org/id/dataset-parameter/929525.rdf
Name: sur
Units: per day
Description: <p>Specific N2 uptake rate</p>
http://lod.bco-dmo.org/id/dataset-parameter/929526.rdf
Name: nfr
Units: nanomoles nitrogen per liter per day (nmol N2/L/day)
Description: <p>N2 fixation rate</p>
http://lod.bco-dmo.org/id/dataset-parameter/929527.rdf
Name: lod
Units: nanomoles nitrogen per liter per day (nmol N2/L/day)
Description: <p>Limit of detection for N2 fixation rate at given sampling location</p>
http://lod.bco-dmo.org/id/dataset-parameter/929528.rdf
Name: loq
Units: nanomoles nitrogen per liter per day (nmol N2/L/day)
Description: <p>Limit of quantification for N2 fixation rate for given incubation experiment</p>
http://lod.bco-dmo.org/id/dataset-parameter/929529.rdf
Name: lod_sur
Units: per day
Description: <p>Limit of detection for specific N2 uptake rate for given incubation experiment</p>
http://lod.bco-dmo.org/id/dataset-parameter/929530.rdf
Name: loq_sur
Units: per day
Description: <p>Limit of quantification for specific N2 uptake rate for given incubation experiment</p>
http://lod.bco-dmo.org/id/dataset-parameter/929531.rdf
Name: det_flag
Units: dimensionless
Description: <p>flag indicates whether N2 uptake was detectable and/or quantifiable; "BDL" indicates that it was below the detection limit; "DNQ" indicates that it was detectable but not quantifiable</p>
http://lod.bco-dmo.org/id/dataset-parameter/929532.rdf
Name: ISO_DateTime_UTC_if_EST
Units: unitless
Description: <p>Datetime of sampling in UTC (if original datetimes were EST or GMT-5)</p>
http://lod.bco-dmo.org/id/dataset-parameter/929533.rdf
Name: ISO_DateTime_UTC_if_EDT
Units: unitless
Description: <p>Datetime of sampling in UTC (if original datetimes were actually EDT or GMT-4)</p>
GB/NERC/BODC > British Oceanographic Data Centre, Natural Environment Research Council, United Kingdom
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
https://osprey.bco-dmo.org/dataset/928568/data/download
download
onLine
dataset
<div class="field" id="form_location">
<p>Nitrogen fixation rates and hydrographic data were measured in July 2019 in&nbsp;conjunction with the SPIROPA (Shelfbreak Productivity Interdisciplinary Research Operation at the Pioneer Array)&nbsp;project cruises (Chief Scientist Dr. Dennis McGillicuddy).&nbsp;This case study was conducted at the Mid-Atlantic Bight shelfbreak front to the south of Massachusetts, USA to examine whether significant N2 fixation occurs in the continental shelf region. On July 5th, 2019, the&nbsp;vessel R/V Thomas G. Thompson (cruise TN368) departed Woods Hole, MA and performed multiple transects in the&nbsp;area of 70 to 71 degrees West longitude and 39 to 40.5 degrees North latitude. Sampling was restricted to waters above the 0.1% light level.&nbsp;</p>
<p>Water was collected in 10L Niskin bottles on a 24-bottle rosette.&nbsp;Vertical conductivity, temperature, and depth profiles were measured&nbsp;concurrently using a Sea-Bird 911+ CTD profiler. Samples to determine nitrate, phosphate, and silicate concentrations were filtered (0.4 um, polycarbonate) directly from the Niskin bottles into acid-washed polyethylene bottles and stored&nbsp;frozen until analysis via standard colorimetric methods at the WHOI Nutrient Analytical Facility using a SEAL Analytical AA3 HR discrete chemistry analyzer. Detection limits for nitrate, phosphate, and silicate methods were 0.040, 0.030 and 0.009 μM, respectively.</p>
<div>
<p>This dataset presents the full incubation result&nbsp;with all replicates. The associated environmental (hydrographic) data is presented in a separate dataset&nbsp;along with the mean uptake and fixation rates. Please refer to BCO-DMO dataset&nbsp;https://www.bco-dmo.org/dataset/927927</p>
</div>
<p>Nitrogen fixation rate measurements (NFR) were quantified on repeat cross-frontal transects using the&nbsp;<sup>15</sup>N<sub>2</sub>&nbsp;bubble release technique (Chang et al., 2019; Klawonn et al., 2015), which is a variant of the <sup>15</sup>N<sub>2</sub> tracer method (Montoya et al., 1996) which accounts for the slow dissolution time of N<sub>2</sub> gas (White et al., 2020).&nbsp; The particular approach used for this study have been described in Selden et al. (2019), Selden, Chappell, et al. (2021), and Selden, Mulholland, et al. (2021). To measure&nbsp;<sup>15</sup>N<sub>2</sub>&nbsp;uptake, triplicate PETG bottles (0.5-2 L) were rinsed with whole water then filled, ensuring that no bubbles remained. Using a gas tight syringe (VICI Precision Sampling),&nbsp;<sup>15</sup>N<sub>2</sub>&nbsp;gas (~99%, Cambridge Isotope Laboratories) was added through a flexible silicon septa. Samples were gently rocked for 15 min as described by Selden et al. (2019). Any remaining bubble was subsequently removed to ensure constant isotopic enrichment over the incubation period, and bottles were incubated on-deck for approximately 24 hours. As the vessel moved across the front, a large temperature gradient was encountered (from 16°C&nbsp;to 26°C).&nbsp;To avoid temperature-shocking the samples during transit, we maintained three on-deck incubators that recirculated water through aquaria chillers (MC-1/10HP, AquaEuroUSA) housed in custom casings (built from King Starboard plastic sheet) for protection and maintained approximate temperature conditions for shelf, frontal, and offshore waters, respectively.</p>
<p>At the end of the incubation period, a 6 milliliter sample aliquot was collected from each bottle and transferred to a helium-purged Exetainer<sup>TM</sup>&nbsp;containing 50 μl zinc chloride (50% w/v). These samples were stored at room temperature and upside-down in 15 ml Falcon<sup>TM</sup>&nbsp;tubes, submerged in ultrapure water, until analysis at the UC Davis Stable Isotope Facility. The remaining incubation volume was then filtered for initial particulate nitrogen (PN) samples. Initial and final PN isotopic composition and concentration were analyzed at Old Dominion University on a Europa 20/20 isotope ratio mass spectrometer with an automated N and carbon preparation module. Low mass samples (&lt;10 µg N) were excluded from downstream analysis as IRMS response can become non-linear at low mass (White et al., 2020).</p>
<p>S<span style="color:rgb(0, 0, 0); font-family:helvetica,arial,sans-serif; font-size:14.4px">pecific uptake rates were calculated following Montoya et al. (1996), with equations detailed below.</span></p>
</div>
Specified by the Principal Investigator(s)
<p>Specific N<sub>2</sub> uptake rates (SUR) were calculated following Montoya et al. (1996):</p>
<p>Equation 1:&nbsp; &nbsp; &nbsp; &nbsp;SUR = (APN_tf - APN_t0) / (AN2 - APN_t0) ] x (1/time)<br />
<br />
where A represents the atom-% enrichment of the initial (t=0) or final (t=f) particulate nitrogen (PN)&nbsp;pool, or the nitrogen (N<sub>2</sub>) pool. Across all experiments, AN2 averaged 3.89 ± 2.0%. Experiments with &lt;1% enrichment were excluded from downstream analysis. The specific uptake rate represents the relative contribution of diazotroph-derived N to PN turnover within a given sample. Absolute N<sub>2</sub> fixation rates (NFR) were calculated as:</p>
<p>Equation 2:&nbsp; &nbsp; &nbsp; &nbsp;NFR = SUR x [PN]<br />
<br />
where [PN] indicates the particulate nitrogen concentration. Limits of detection and quantification were calculated per incubation by propagating the minimum detectable difference between initial and final <sup>15</sup>N atom-% enrichment of the PN pool (3σ and 10σ), three sigma and ten sigma respectively, n≥7, 12.5 µg N standards measured daily&nbsp;through Eqn. 2 (Ripp, 1996; White et al. 2020). A rate was only considered detectable if two of three replicate incubations yielded detectable rates.</p>
Specified by the Principal Investigator(s)
- Imported data from source file "Selden_JGR24_Nfix_rates_per_bottle.csv" into the BCO-DMO data system.
- Changed date format from m/d/yyyy to yyyy-mm-dd (ISO Date 8601 format) and converted datetimes from EST to UTC.
- Added latitude and longitude columns based on datetimes and depths.
- Added official cruise ID corresponding to the the provided deployment and cruise name
- Rounded values according to the PI’s/submitter’s indicated precision
- Modified parameter (column) names to conform with BCO-DMO naming conventions. The only allowed characters are A-Z,a-z,0-9, and underscores. No spaces, hyphens, commas, parentheses, or Greek letters.
Specified by BCO-DMO Data Managers
asNeeded
7.x-1.1
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
AquaEuroUSA Aquaria chillers (MC-1/10HP)
AquaEuroUSA Aquaria chillers (MC-1/10HP)
PI Supplied Instrument Name: AquaEuroUSA Aquaria chillers (MC-1/10HP) PI Supplied Instrument Description:To avoid temperature-shocking the samples, three on-deck incubators recirculated water through aquaria chillers (MC-1/10HP, AquaEuroUSA) housed in custom casings. Instrument Name: Aquarium chiller Instrument Short Name:Aquarium chiller Instrument Description: Immersible or in-line liquid cooling device, usually with temperature control.
incubator
incubator
PI Supplied Instrument Name: incubator PI Supplied Instrument Description:To avoid temperature-shocking the samples, three on-deck incubators recirculated water through aquaria chillers. Instrument Name: Incubator Instrument Short Name:incubator (general) Instrument Description: A device in which environmental conditions (light, photoperiod, temperature, humidity, etc.) can be controlled.
Note: we have more specific terms for shipboard incubators (https://www.bco-dmo.org/instrument/629001) and in-situ incubators (https://www.bco-dmo.org/instrument/494).
Europa 20/20 isotope ratio mass spectrometer with automated nitrogen and carbon preparation module
Europa 20/20 isotope ratio mass spectrometer with automated nitrogen and carbon preparation module
PI Supplied Instrument Name: Europa 20/20 isotope ratio mass spectrometer with automated nitrogen and carbon preparation module PI Supplied Instrument Description:Initial and final PN isotopic composition and concentration were analyzed on a Europa 20/20 isotope ratio mass spectrometer with an automated N and carbon preparation module. Instrument Name: Isotope-ratio Mass Spectrometer Instrument Short Name:IR Mass Spec; IRMS Instrument 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). Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/
Niskin bottle
Niskin bottle
PI Supplied Instrument Name: Niskin bottle PI Supplied Instrument Description:A CTD rosette equipped with 24 10L Niskin bottles was used to sample water in the Mid Atlantic Bight Instrument Name: Niskin bottle Instrument Short Name:Niskin bottle Instrument 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. Community Standard Description: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/
Cruise: TN368
TN368
R/V Thomas G. Thompson
Community Standard Description
International Council for the Exploration of the Sea
R/V Thomas G. Thompson
vessel
TN368
Dennis J. McGillicuddy
Woods Hole Oceanographic Institution
R/V Thomas G. Thompson
Community Standard Description
International Council for the Exploration of the Sea
R/V Thomas G. Thompson
vessel