http://lod.bco-dmo.org/id/dataset/886679
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
2023-01-12
ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data
ISO 19115-2:2009(E)
Radiocarbon dating of archived sediment cores in the Southeast Pacific from 1960 to 2000
2023-01-12
publication
2023-01-12
revision
Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)
2023-01-17
publication
https://doi.org/10.26008/1912/bco-dmo.886679.1
Mark A. Altabet
University of Massachusetts Dartmouth
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: Altabet, M. A. (2023) Radiocarbon dating of archived sediment cores in the Southeast Pacific from 1960 to 2000. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2023-01-12 [if applicable, indicate subset used]. doi:10.26008/1912/bco-dmo.886679.1 [access date]
Methods and Sampling: <p>This dataset was developed for sediment cores from the SE Pacific that were archived in a variety of repositories. The most promising cores were selected for radiocarbon dating of the planktonic foraminiferal fraction.&nbsp; Sediment handling and processing were similar to Cleaveland and Herbert (2007). &nbsp;Sediment samples of 2 cc size were requested from the core libraries where the target cores have been archived. &nbsp;Upon delivery, they were kept refrigerated. &nbsp;Bulk calcium carbonate for radiocarbon dating was isolated from the greater than 150-millimeter (mm) fraction of wet-sieved bulk sediment and dried prior to analysis.</p>
<p>Samples were sent to the WHOI NOSAMS facility and were prepared according to the methods for carbonate <sup>14</sup>C analysis listed at https://www2.whoi.edu/site/nosams/client-services/submitting_guidelines/sample_processes (see related publications).</p>
<p>Carbonate samples are treated with phosphoric acid to generate CO2 which, in turn, is converted to a graphite target. The target is analyzed for <sup>14</sup>C on an accelerator mass spectrometer (AMS).</p>
<p>Carbonate samples are treated with phosphoric acid while under vacuum.&nbsp; The acidification of the sample material generates carbon dioxide (CO<sub>2</sub>) which is then converted to graphite.&nbsp; The graphite is pressed into a target to be analyzed for <sup>14</sup>C on an accelerator mass spectrometer (AMS).</p>
<p>&nbsp;</p>
<p>&nbsp;</p>
Funding provided by NSF Division of Ocean Sciences (NSF OCE) Award Number: OCE-1602810 Award URL: https://www.nsf.gov/awardsearch/show-award?AWD_ID=1602810
completed
Mark A. Altabet
University of Massachusetts Dartmouth
508-999-8622
706 S. Rodney French Blvd
New Bedford
MA
02067
USA
maltabet@umassd.edu
pointOfContact
asNeeded
Dataset Version: 1
Unknown
Sediment_Core_ID
Core_latitude
Core_Longitude
Depth_in_core
Measured_Fraction_Modern
Measured_Fraction_Modern_Error
Radiocarbon_Age
Radiocarbon_Age_Error
WHOI NOSAMS Accelerator Mass Spectrometer
theme
None, User defined
core id
latitude
longitude
depth core
14C
standard error
carbon-14 age dating
featureType
BCO-DMO Standard Parameters
Accelerator Mass Spectrometer
instrument
BCO-DMO Standard Instruments
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: Did the SE Pacific Gyre become a Hot Spot for N2 Fixation during Dusty Glacial Conditions?
https://osprey.bco-dmo.org/project/884849
Collaborative Research: Did the SE Pacific Gyre become a Hot Spot for N2 Fixation during Dusty Glacial Conditions?
<p><strong>NSF Award Abstract</strong><br />
The element nitrogen is a fundamental component of all living things and its cycling through the environment is an important component of Earth's biosphere. As a vital nutrient, the availability of nitrogen in a biologically usable form often "limits" the growth of plants both on land as well as in the ocean. Paradoxically, nitrogen is very abundant as dinitrogen gas (N2) in both the Earth's atmosphere and dissolved in seawater. However in this chemical form, nitrogen cannot be used by most living things. Only a small subset of microbes has the ability to "fix" N2 gas, that is, to convert it into a biologically usable chemical form. Thus, these N2 fixing organisms provide a critical environmental function sustaining life on this planet. In the ocean, N2 fixation is a major control on the total amount of biologically available nitrogen, balancing over the time losses back to N2 gas. The amount of biologically available nitrogen in turn controls the growth (productivity) of photosynthetic organisms (phytoplankton) in the sunlit region of the surface ocean which form the base of the food chain and contribute to oceanic control of the atmospheric levels of greenhouse gases.</p>
<p>This project concerns itself with understanding the fundamental, large-scale controls of oceanic N2 fixation and how they are influenced by climate change over time. N2 fixing microbes themselves appeared to be limited by the availability of other nutrient elements such as phosphorous and iron. While it is known in which parts of the ocean there is at present greater or lesser availability of phosphorous and iron, it remains unclear if either is of overriding importance or if changes in the past produced significant variations in N2 fixation. Past changes in N2 fixation may have been an important feedback on oceanic control of atmospheric greenhouse gases. Understanding these past changes and their controls will provide the knowledge base for improving prediction of how ocean N2 fixation may respond to future changes in climate. This is of great societal relevance as changes in oceanic N2 fixation will ultimately impact marine ecosystems and living resources as feedback on the greenhouse gases driving climate change.</p>
<p>To address these questions, the research team will undertake a study the climate-sensitivity of N2 fixation in the southeast Pacific gyre over the last glacial cycle as well as its plausible "master controls". This oligotrophic region experiences little modern N2 fixation despite proximity to a large supply of excess phosphate from the adjacent Peru-Chile oxygen minimum zone. This is consistent with modern iron limitation due to low aeolian supply that would have been relieved during past dusty conditions. The research team will use the natural experiment of the last full glacial cycle, captured in the foraminiferal-bound N isotopes of gyre sites as well as sites at its southern margin, to probe controls on the marine N cycle exerted by variable dust inputs and changes in N-loss in the adjacent oxygen minimum zone, and relate these to known changes in greenhouse forcing of climate. Through numerical modeling, the research team will also consider whether past variations in N2 fixation in this region may have impacted the global ocean N cycle and budget.</p>
<p>This project will also fund the training of undergraduate and graduate students and support participation of high school students from underrepresented groups in original research. The research team will continue their outreach efforts through established partnerships with elementary, middle, and high schools, engaging a diverse school population and their families with exciting and relevant science.</p>
N2 Fixation Glacial Dust Pacific Gyre
largerWorkCitation
project
eng; USA
oceans
-120.193
-73.608
-44.55
-17
1960-01-01
2000-01-31
Southeast Pacific Gyre
0
BCO-DMO catalogue of parameters from Radiocarbon dating of archived sediment cores in the Southeast Pacific from 1960 to 2000
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/886696.rdf
Name: Sediment_Core_ID
Units: unitless
Description: <p>Core designation at the time of collection and used by the core library where it is archived. All cores were piston cores except when a trigger core was available and then 'PC' or 'TC' is added to the designation. 'replicate' indicates a replicate analysis from the same sediment sample</p>
http://lod.bco-dmo.org/id/dataset-parameter/886697.rdf
Name: Core_latitude
Units: decimal degrees
Description: <p>Latitude of the core site North (South is negative)</p>
http://lod.bco-dmo.org/id/dataset-parameter/886698.rdf
Name: Core_Longitude
Units: decimal degrees
Description: <p>Longitude of the core site East (West is negative)</p>
http://lod.bco-dmo.org/id/dataset-parameter/886699.rdf
Name: Depth_in_core
Units: centimeters (cm)
Description: <p>Depth below core top from which the sample was taken</p>
http://lod.bco-dmo.org/id/dataset-parameter/886700.rdf
Name: Measured_Fraction_Modern
Units: unitless
Description: <p>Fraction of modern radiocarbon in the sample as measured by the AMS</p>
http://lod.bco-dmo.org/id/dataset-parameter/886701.rdf
Name: Measured_Fraction_Modern_Error
Units: unitless
Description: <p>± Error in fraction of modern radiocarbon determined by NOSAMS</p>
http://lod.bco-dmo.org/id/dataset-parameter/886702.rdf
Name: Radiocarbon_Age
Units: unitless
Description: <p>Radiocarbon age derived from fraction of modern radiocarbon. Where a '>' is shown, statistical certainty permitted only a lower bound to be determined.</p>
http://lod.bco-dmo.org/id/dataset-parameter/886703.rdf
Name: Radiocarbon_Age_Error
Units: unitless
Description: <p>Age error determined from the error in fraction of modern radiocarbon, in years. Where age was only lower bounded no error is calculated.</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
3068
https://darchive.mblwhoilibrary.org/bitstream/1912/29614/1/dataset-886679_radiocarbon-dating-southeast-pacific-sediment-cores__v1.tsv
download
https://doi.org/10.26008/1912/bco-dmo.886679.1
download
onLine
dataset
<p>This dataset was developed for sediment cores from the SE Pacific that were archived in a variety of repositories. The most promising cores were selected for radiocarbon dating of the planktonic foraminiferal fraction.&nbsp; Sediment handling and processing were similar to Cleaveland and Herbert (2007). &nbsp;Sediment samples of 2 cc size were requested from the core libraries where the target cores have been archived. &nbsp;Upon delivery, they were kept refrigerated. &nbsp;Bulk calcium carbonate for radiocarbon dating was isolated from the greater than 150-millimeter (mm) fraction of wet-sieved bulk sediment and dried prior to analysis.</p>
<p>Samples were sent to the WHOI NOSAMS facility and were prepared according to the methods for carbonate <sup>14</sup>C analysis listed at https://www2.whoi.edu/site/nosams/client-services/submitting_guidelines/sample_processes (see related publications).</p>
<p>Carbonate samples are treated with phosphoric acid to generate CO2 which, in turn, is converted to a graphite target. The target is analyzed for <sup>14</sup>C on an accelerator mass spectrometer (AMS).</p>
<p>Carbonate samples are treated with phosphoric acid while under vacuum.&nbsp; The acidification of the sample material generates carbon dioxide (CO<sub>2</sub>) which is then converted to graphite.&nbsp; The graphite is pressed into a target to be analyzed for <sup>14</sup>C on an accelerator mass spectrometer (AMS).</p>
<p>&nbsp;</p>
<p>&nbsp;</p>
Specified by the Principal Investigator(s)
<p>Data processing including error estimates are as in https://www2.whoi.edu/site/nosams/client-services/radiocarbon-data-calculations/ and as in Stuvier and Polach (1977).</p>
<p>In short, the fraction of <sup>14</sup>C expected for modern samples (FM) is calculated from the AMS-measured <sup>14</sup>C/<sup>12</sup>C ratio. &nbsp;The radiocarbon age is then calculated from the radioactive decay equation and decay constant for <sup>14</sup>C. &nbsp;Where warranted corrections were made by NOSAMS for background <sup>14</sup>C.</p>
<p><strong>BCO-DMO Processing Description:</strong><br />
- Adjusted field/parameter names to comply with BCO-DMO naming conventions<br />
- Added a conventional header with dataset name, PI names, version date<br />
<br />
&nbsp;</p>
Specified by the Principal Investigator(s)
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
WHOI NOSAMS Accelerator Mass Spectrometer
WHOI NOSAMS Accelerator Mass Spectrometer
PI Supplied Instrument Name: WHOI NOSAMS Accelerator Mass Spectrometer PI Supplied Instrument Description:The WHOI NOSAMS Accelerator Mass Spectrometer is as described in https://www2.whoi.edu/site/nosams/about/laboratory-capabilities/ams-instruments/ Instrument Name: Accelerator Mass Spectrometer Instrument Short Name:AMS Instrument Description: An AMS measures "long-lived radionuclides that occur naturally in our environment. AMS uses a particle accelerator in conjunction with ion sources, large magnets, and detectors to separate out interferences and count single atoms in the presence of 1x1015 (a thousand million million) stable atoms, measuring the mass-to-charge ratio of the products of sample molecule disassociation, atom ionization and ion acceleration." AMS permits ultra low-level measurement of compound concentrations and isotope ratios that traditional alpha-spectrometry cannot provide. More from Purdue University: http://www.physics.purdue.edu/primelab/introduction/ams.html Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/LAB17/