http://lod.bco-dmo.org/id/dataset/732754
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
2018-03-30
ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data
ISO 19115-2:2009(E)
N isotope data for individual amino acids from modern west Antarctic seals
2018-03-30
publication
2018-03-30
revision
Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)
2022-08-22
publication
https://doi.org/10.26008/1912/bco-dmo.732754.1
Brenda Hall
University of Maine
principalInvestigator
Paul L. Koch
University of California-Santa Cruz
principalInvestigator
Daniel P. Costa
University of California-Santa Cruz
principalInvestigator
A. Rus Hoelzel
Durham 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: Hall, B., Koch, P. L., Costa, D. P., Hoelzel, A. R. (2022) N isotope data for individual amino acids from modern west Antarctic seals. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2018-03-30 [if applicable, indicate subset used]. doi:10.26008/1912/bco-dmo.732754.1 [access date]
N isotope data for individual amino acids from modern west Antarctic seals Dataset Description: <p><strong>These data are published and discussed in:</strong><br />
Brault, E. (2017). An Examination of the Ecological and Oceanographic Effects of Mid-to-Late Holocene Climate Changes on the Ross Sea Ecosystem. UC Santa Cruz. ProQuest ID: Brault_ucsc_0036E_11435. Merritt ID: ark:/13030/m5dg1n5d. Retrieved from&nbsp;<a href="https://escholarship.org/uc/item/99s5j3fk" target="_blank">https://escholarship.org/uc/item/99s5j3fk</a></p> Methods and Sampling: <p><strong>Sampling Sites and Sample Collection:</strong><br />
Tissue samples from Ross, Weddell, and crabeater seals were collected along western Antarctica from the West Antarctic Peninsula (WAP) to the Ross Sea during multiple field seasons and, in most cases, body mass, age class (juvenile, subadult, and adult), gender, and location were recorded for each sampled seal. Seals were sampled during the austral summers of 2008/09 and 2010/11 on RV Oden cruises along the western Antarctic coast. Mostly whole blood samples were obtained. In some cases, clot (blood with serum removed), red blood cells (RBCs, whole blood exposed to an anticoagulant, heparin, before having plasma removed), and hair samples (body fur or whiskers) were also taken. The sampling protocol is described in Aubail et al. (2011); all animal captures were conducted in accordance with the regulations of the Swedish Polar Research Secretariat (Registration No. 2010-112).</p>
<p>All other samples were obtained from animal captures conducted under National Marine Fisheries Service permit No. 87-1851-00. Additionally, the Institutional Animal Care and Use Committee (IACUC) at the University of Santa Cruz (UC Santa Cruz) approved all protocols for the following samples. Whiskers were taken from crabeater seals during multiple cruises on the RV Lawrence M. Gould along the WAP.&nbsp; Plasma was also obtained from a few of the fall 2007 individuals (G105, G110, and G112). In addition, serum or plasma was obtained from two Weddell seals during the fall 2007 sampling in this region, and whiskers were taken from two WAP Weddell seals in the austral summer of 2009/10. Hückstädt et al. (2012b) describe the procedure for sampling the whiskers, and Goetz et al. (2017) describe the protocol used for collecting the seal serum and plasma.</p>
<p>Several blood samples were obtained from Weddell seals in the McMurdo Sound region, Ross Sea, Antarctica over multiple field seasons. Twelve whole blood samples were taken from juvenile Weddell seals near Inexpressible Island (74.9 °S, 163.7 °E) during the austral summer of 2010/11. Whole blood samples were taken from Weddell seals in the austral summer of 2010/11 and austral spring of 2012. RBCs were sampled in the austral summer of 2009/10, austral summer of 2011/12, and austral spring of 2012. Whole blood, plasma, and serum were obtained from five Weddell seals sampled in the austral spring of 2015, and whole blood from an additional seven Weddell seals was also acquired during this time. Goetz et al. (2017) describe the sampling protocol for these Weddell seals.</p>
<p>Lastly, a few samples were obtained from crabeater seals in McMurdo Sound. Hair samples were taken from three recently deceased juvenile crabeater seals that were found on the seasonal pack ice around Cape Royds in the austral summer of 2009/10. Whole blood was sampled, using the protocol of Goetz et al. (2017), from a male adult crabeater seal found in Erebus Bay during the austral summer of 2010/11.</p>
<p><strong>Taxonomic Groups:</strong><br />
Pinnipedia<br />
&nbsp;&nbsp;&nbsp;&nbsp; Phocidae<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <em>Lobodon carcinophaga</em> - crabeater seal<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <em>Ommatophoca rossii </em>- Ross seal<br />
<em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Leptonychotes weddellii </em>- Weddell seal</p>
<p><strong>Sample Preparation:</strong><br />
After sample collection, all samples were kept frozen at -20 °C. Blood samples were freeze-dried with a Labconco Freeze Dry System (Lyph Lock 4.5) and homogenized manually prior to analysis. Lipid extraction was not performed on the blood samples. Blood has a relatively low lipid content and a test set of blood samples with and without lipid extraction revealed no significant effect of lipid extraction on blood values. Hair samples, which have higher lipid contents, were lipid extracted. Hair samples were washed with Milli-Q water (Thermo Fisher Scientific, Inc.) and then rinsed 3 times in an ultrasonic bath with petroleum ether for 15 minutes. Hückstädt et al. (2012a) used a similar protocol to lipid-extract the crabeater seal whisker samples.</p>
<p><strong>Compound Specific Isotope Analysis (CSIA):</strong><br />
CSIA was performed at UC Santa Cruz via gas chromatography-isotope ratio mass spectrometry (GC-IRMS). All samples were prepared for GC-IRMS analysis using the method described in McCarthy et al. (2007) and McCarthy et al. (2013). In brief, samples were hydrolyzed (6 N HCl for 20 hr at 110 °C) and converted to trifluoroacetic anhydride (TFAA) derivatives. Samples were stored in a -20 °C freezer in a 1:3 TFAA:DCM (methylene chloride) mixture until the day of instrumental analysis. Immediately before the analysis, the TFAA:DCM mixture was evaporated under N<sub>2</sub> and samples were diluted in ethyl acetate.</p>
<p>Amino acid δ<sup>15</sup>N values were measured on a Thermo Trace GC coupled to a Thermo-Finnigan Delta<sup>Plus</sup> XP isotope-ratio-monitoring mass spectrometer (oxidation furnace at 980 ºC and reduction furnace at 650 ºC). The column for the N isotope analysis was a SGE Analytical Science BPX5 column 60 m by 0.32 mm with a 1 µm film thickness. The injector temperature was 250 ºC with a split He flow of 2 mL/min. The GC temperature program for δ<sup>15</sup>N analysis was: initial temp = 70 ºC hold for 1 min; ramp 1 = 10 ºC /min to 185 ºC, hold for 2 min; ramp 2 = 2 ºC/min to 200 ºC, hold for 10 min; ramp 3 = 30 ºC/min to 300 ºC, hold for 6 min. Directly measured amino acid δ<sup>15</sup>N values were corrected based on bracketing external standards, as described in McCarthy et al. (2013).</p>
<p>Samples were injected and analyzed 3 to 4 times, and the mean value, standard deviation, and number of injections are reported. The δ<sup>15</sup>N values of 11 amino acids could be quantified. These were alanine (Ala), glycine (Gly), threonine (Thr), serine (Ser), valine (Val), leucine (Leu), Pro, aspartic acid + asparagine (Asp), Glu, Phe, and lysine (Lys). In all samples, isoleucine (Ile) was either not detectable or had low peak areas (&lt; 70) and, thus, Ile δ<sup>15</sup>N values should be considered with caution. Lysine was not detected in one sample (R101) and not in all injections of a few samples (R114, W006, and W013), but peak areas were sufficient (&gt;70) when it was detectable.</p>
Funding provided by NSF Office of Polar Programs (formerly NSF PLR) (NSF OPP) Award Number: OPP-1141849 Award URL: https://www.nsf.gov/awardsearch/show-award?AWD_ID=1141849
Funding provided by NSF Office of Polar Programs (formerly NSF PLR) (NSF OPP) Award Number: OPP-1142108 Award URL: https://www.nsf.gov/awardsearch/show-award?AWD_ID=1142108
completed
Brenda Hall
University of Maine
207-581-2191
School of Earth and Climate Sciences 5790 Bryand Global Sciences Center
Orono
ME
04469
US
brendah@maine.edu
pointOfContact
Paul L. Koch
University of California-Santa Cruz
831-234-9437
1156 High Street
Santa Cruz
CA
95064-1077
USA
plkoch@ucsc.edu
pointOfContact
Daniel P. Costa
University of California-Santa Cruz
831-459-2786
Dept. of Ecology and Evolutionary Biology, Ocean Health Building 100 Shaffer Road
Santa Cruz
CA
95060
USA
costa@ucsc.edu
pointOfContact
A. Rus Hoelzel
Durham University
44-0-191-3341325
Dept. of Biosciences, Durham University Stockton Road
Durham DH1 3LE
UK
a.r.hoelzel@durham.ac.uk
pointOfContact
asNeeded
Dataset Version: 1
Unknown
Common_name
Scientific_name
WoRMS_LSID
AphiaID
Sample_ID
Region
Latitude
Longitude
Calendar_age
Age_class
Gender
Sample_type
Amino_acid
d15N
N_std_dev
injections
GC-IRMS
theme
None, User defined
common_name
taxon
Life Science Identifier (LSID)
taxon_code
sample identification
site description
latitude
longitude
No BCO-DMO term
ageclass
sex
sample type
amino acid name
d15N measured in biota
number
featureType
BCO-DMO Standard Parameters
Isotope-ratio 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: Exploring the Vulnerability of Southern Ocean Pinnipeds to Climate Change - An Integrated Approach
https://osprey.bco-dmo.org/project/726874
Collaborative Research: Exploring the Vulnerability of Southern Ocean Pinnipeds to Climate Change - An Integrated Approach
<p><em>NSF abstract:</em><br />
Building on previously funded NSF research, the use of paleobiological and paleogenetic data from mummified elephant seal carcasses found along the Dry Valleys and Victoria Land Coast in areas that today are too cold to support seal colonies (Mirougina leonina; southern elephant seals; SES) supports the former existence of these seals in this region. The occurrence and then subsequent disappearance of these SES colonies is consistent with major shifts in the Holocene climate to much colder conditions at the last ~1000 years BCE).</p>
<p>Further analysis of the preserved remains of three other abundant pinnipeds ? crabeater (Lobodon carciophagus), Weddell (Leptonychotes weddelli) and leopard (Hydrurga leptonyx) will be studied to track changes in their population size (revealed by DNA analysis) and their diet (studied via stable isotope analysis). Combined with known differences in life history, preferred ice habitat and ecosystem sensitivity among these species, this paleoclimate proxy data will be used to assess their exposure and sensitivity to climate change in the Ross Sea region during the past ~1-2,000 years</p>
Southern Ocean Pinnipeds
largerWorkCitation
project
eng; USA
oceans
162.684
175.143
-77.652
-62.47
2008-01-01
2011-12-31
McMurdo Dry Valleys Region; Royal Society Range, Victoria Land Coast , Antarctic Peninsula, Amundsen Sea, Ross Sea
0
BCO-DMO catalogue of parameters from N isotope data for individual amino acids from modern west Antarctic seals
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/732767.rdf
Name: Common_name
Units: unitless
Description: <p>Common name of the seal</p>
http://lod.bco-dmo.org/id/dataset-parameter/732768.rdf
Name: Scientific_name
Units: unitless
Description: <p>Scientific name (genus and species) of the seal</p>
http://lod.bco-dmo.org/id/dataset-parameter/732769.rdf
Name: WoRMS_LSID
Units: unitless
Description: <p>Life Science Identifier (LSID) assigned to the species by the World Register of Marine Species (WoRMS; <a href="http://www.marinespecies.org/">http://www.marinespecies.org/</a>)</p>
http://lod.bco-dmo.org/id/dataset-parameter/732770.rdf
Name: AphiaID
Units: unitless
Description: <p>World Register of Marine Species (WoRMS; <a href="http://www.marinespecies.org/">http://www.marinespecies.org/</a>) species identifier</p>
http://lod.bco-dmo.org/id/dataset-parameter/732771.rdf
Name: Sample_ID
Units: unitless
Description: <p>Sample identification code</p>
http://lod.bco-dmo.org/id/dataset-parameter/732772.rdf
Name: Region
Units: unitless
Description: <p>General location of sampling</p>
http://lod.bco-dmo.org/id/dataset-parameter/732773.rdf
Name: Latitude
Units: decimal degrees
Description: <p>Latitude of sample collection (negative values = south)</p>
http://lod.bco-dmo.org/id/dataset-parameter/732774.rdf
Name: Longitude
Units: decimal degrees
Description: <p>Longitude of sample collection (negative values = west; positive values = east)</p>
http://lod.bco-dmo.org/id/dataset-parameter/732775.rdf
Name: Calendar_age
Units: unitless
Description: <p>Calendar age of specimen</p>
http://lod.bco-dmo.org/id/dataset-parameter/732776.rdf
Name: Age_class
Units: unitless
Description: <p>Age class of the specimen (subadult, adult)</p>
http://lod.bco-dmo.org/id/dataset-parameter/732777.rdf
Name: Gender
Units: unitless
Description: <p>Sex of the specimen (male, female)</p>
http://lod.bco-dmo.org/id/dataset-parameter/732778.rdf
Name: Sample_type
Units: unitless
Description: <p>Description of the type of tissue analyzed (clotted blood, plasma, whisker, whole blood)</p>
http://lod.bco-dmo.org/id/dataset-parameter/732779.rdf
Name: Amino_acid
Units: unitless
Description: <p>Amino acid analyzed</p>
http://lod.bco-dmo.org/id/dataset-parameter/732780.rdf
Name: d15N
Units: permil (‰), AIR
Description: <p>Stable nitrogen isotope value</p>
http://lod.bco-dmo.org/id/dataset-parameter/732781.rdf
Name: N_std_dev
Units: permil (‰), AIR
Description: <p>Standard deviation of d15N values</p>
http://lod.bco-dmo.org/id/dataset-parameter/732782.rdf
Name: injections
Units: unitless
Description: <p>Number of sample injections on GC-IRMS</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
41346
https://darchive.mblwhoilibrary.org/bitstream/1912/29245/1/dataset-732754_modern-seal-amino-acid-isotopes__v1.tsv
download
https://doi.org/10.26008/1912/bco-dmo.732754.1
download
onLine
dataset
<p><strong>Sampling Sites and Sample Collection:</strong><br />
Tissue samples from Ross, Weddell, and crabeater seals were collected along western Antarctica from the West Antarctic Peninsula (WAP) to the Ross Sea during multiple field seasons and, in most cases, body mass, age class (juvenile, subadult, and adult), gender, and location were recorded for each sampled seal. Seals were sampled during the austral summers of 2008/09 and 2010/11 on RV Oden cruises along the western Antarctic coast. Mostly whole blood samples were obtained. In some cases, clot (blood with serum removed), red blood cells (RBCs, whole blood exposed to an anticoagulant, heparin, before having plasma removed), and hair samples (body fur or whiskers) were also taken. The sampling protocol is described in Aubail et al. (2011); all animal captures were conducted in accordance with the regulations of the Swedish Polar Research Secretariat (Registration No. 2010-112).</p>
<p>All other samples were obtained from animal captures conducted under National Marine Fisheries Service permit No. 87-1851-00. Additionally, the Institutional Animal Care and Use Committee (IACUC) at the University of Santa Cruz (UC Santa Cruz) approved all protocols for the following samples. Whiskers were taken from crabeater seals during multiple cruises on the RV Lawrence M. Gould along the WAP.&nbsp; Plasma was also obtained from a few of the fall 2007 individuals (G105, G110, and G112). In addition, serum or plasma was obtained from two Weddell seals during the fall 2007 sampling in this region, and whiskers were taken from two WAP Weddell seals in the austral summer of 2009/10. Hückstädt et al. (2012b) describe the procedure for sampling the whiskers, and Goetz et al. (2017) describe the protocol used for collecting the seal serum and plasma.</p>
<p>Several blood samples were obtained from Weddell seals in the McMurdo Sound region, Ross Sea, Antarctica over multiple field seasons. Twelve whole blood samples were taken from juvenile Weddell seals near Inexpressible Island (74.9 °S, 163.7 °E) during the austral summer of 2010/11. Whole blood samples were taken from Weddell seals in the austral summer of 2010/11 and austral spring of 2012. RBCs were sampled in the austral summer of 2009/10, austral summer of 2011/12, and austral spring of 2012. Whole blood, plasma, and serum were obtained from five Weddell seals sampled in the austral spring of 2015, and whole blood from an additional seven Weddell seals was also acquired during this time. Goetz et al. (2017) describe the sampling protocol for these Weddell seals.</p>
<p>Lastly, a few samples were obtained from crabeater seals in McMurdo Sound. Hair samples were taken from three recently deceased juvenile crabeater seals that were found on the seasonal pack ice around Cape Royds in the austral summer of 2009/10. Whole blood was sampled, using the protocol of Goetz et al. (2017), from a male adult crabeater seal found in Erebus Bay during the austral summer of 2010/11.</p>
<p><strong>Taxonomic Groups:</strong><br />
Pinnipedia<br />
&nbsp;&nbsp;&nbsp;&nbsp; Phocidae<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <em>Lobodon carcinophaga</em> - crabeater seal<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <em>Ommatophoca rossii </em>- Ross seal<br />
<em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Leptonychotes weddellii </em>- Weddell seal</p>
<p><strong>Sample Preparation:</strong><br />
After sample collection, all samples were kept frozen at -20 °C. Blood samples were freeze-dried with a Labconco Freeze Dry System (Lyph Lock 4.5) and homogenized manually prior to analysis. Lipid extraction was not performed on the blood samples. Blood has a relatively low lipid content and a test set of blood samples with and without lipid extraction revealed no significant effect of lipid extraction on blood values. Hair samples, which have higher lipid contents, were lipid extracted. Hair samples were washed with Milli-Q water (Thermo Fisher Scientific, Inc.) and then rinsed 3 times in an ultrasonic bath with petroleum ether for 15 minutes. Hückstädt et al. (2012a) used a similar protocol to lipid-extract the crabeater seal whisker samples.</p>
<p><strong>Compound Specific Isotope Analysis (CSIA):</strong><br />
CSIA was performed at UC Santa Cruz via gas chromatography-isotope ratio mass spectrometry (GC-IRMS). All samples were prepared for GC-IRMS analysis using the method described in McCarthy et al. (2007) and McCarthy et al. (2013). In brief, samples were hydrolyzed (6 N HCl for 20 hr at 110 °C) and converted to trifluoroacetic anhydride (TFAA) derivatives. Samples were stored in a -20 °C freezer in a 1:3 TFAA:DCM (methylene chloride) mixture until the day of instrumental analysis. Immediately before the analysis, the TFAA:DCM mixture was evaporated under N<sub>2</sub> and samples were diluted in ethyl acetate.</p>
<p>Amino acid δ<sup>15</sup>N values were measured on a Thermo Trace GC coupled to a Thermo-Finnigan Delta<sup>Plus</sup> XP isotope-ratio-monitoring mass spectrometer (oxidation furnace at 980 ºC and reduction furnace at 650 ºC). The column for the N isotope analysis was a SGE Analytical Science BPX5 column 60 m by 0.32 mm with a 1 µm film thickness. The injector temperature was 250 ºC with a split He flow of 2 mL/min. The GC temperature program for δ<sup>15</sup>N analysis was: initial temp = 70 ºC hold for 1 min; ramp 1 = 10 ºC /min to 185 ºC, hold for 2 min; ramp 2 = 2 ºC/min to 200 ºC, hold for 10 min; ramp 3 = 30 ºC/min to 300 ºC, hold for 6 min. Directly measured amino acid δ<sup>15</sup>N values were corrected based on bracketing external standards, as described in McCarthy et al. (2013).</p>
<p>Samples were injected and analyzed 3 to 4 times, and the mean value, standard deviation, and number of injections are reported. The δ<sup>15</sup>N values of 11 amino acids could be quantified. These were alanine (Ala), glycine (Gly), threonine (Thr), serine (Ser), valine (Val), leucine (Leu), Pro, aspartic acid + asparagine (Asp), Glu, Phe, and lysine (Lys). In all samples, isoleucine (Ile) was either not detectable or had low peak areas (&lt; 70) and, thus, Ile δ<sup>15</sup>N values should be considered with caution. Lysine was not detected in one sample (R101) and not in all injections of a few samples (R114, W006, and W013), but peak areas were sufficient (&gt;70) when it was detectable.</p>
Specified by the Principal Investigator(s)
<p><strong>BCO-DMO Processing:</strong><br />
-modifed parameter names (replaced spaces with underscores);<br />
-added the LSID and AphiaID from WoRMS;<br />
-replaced spaces with underscores in all columns;<br />
-replaced "&amp;" in data Region column with "and";<br />
-sorted by Common_name.</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
GC-IRMS
GC-IRMS
PI Supplied Instrument Name: GC-IRMS PI Supplied Instrument Description:CSIA was performed at UC Santa Cruz via gas chromatography-isotope ratio mass spectrometry (GC-IRMS). Amino acid δ15N values were measured on a Thermo Trace GC coupled to a Thermo-Finnigan DeltaPlus XP isotope-ratio-monitoring mass spectrometer (oxidation furnace at 980 ºC and reduction furnace at 650 ºC). 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/