Experimental data (d15N and d13C) from a starvation experiment with scleractinian cold-water coral Balanophyllia elegans collected at Friday Harbor, WA with experiments conducted between 2020 and 2022

Website: https://www.bco-dmo.org/dataset/919993
Data Type: experimental
Version: 1
Version Date: 2024-02-09

Project
» Collaborative Research: Refining the use of scleractinian cold-water coral skeleton-bound d15N as a proxy for marine N cycling (Coral-bound N)
ContributorsAffiliationRole
Gothmann, Anne M.Saint Olaf CollegeCo-Principal Investigator
Granger, JulieUniversity of Connecticut (UConn)Co-Principal Investigator
Prokopenko, MariaPomona College (Pomona)Co-Principal Investigator
Mottram, JosieSaint Olaf CollegeStudent
York, Amber D.Woods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
Data collected to determine if starvation affects dietary isotopic offset. These data were collected as part of the following study: Data collected as part of this study include nitrogen isotope ratio data for coral tissue and skeleton of the scleractinian cold-water coral Balanophyllia elegans collected at Friday Harbor, WA. Data was collected between March 2019 and August 2021. These data include paired measurements of the N isotope ratio (d15N) of coral tissue and skeleton. Tissue was measured using and Elemental Analyzer (EA)-coupled Isotope Ratio Mass Spectrometer (IRMS) and skeleton samples were first dissolved and organic nitrogen was oxidized to nitrate with persulfate before being run on a GC-IRMS with the denitrifier method. These data also include the results of two culture experiments with the same species of corals. The corals in the first culture experiment were fed Artemia diets with different known d15N in order to quantify change in the tissue d15N in response to a change in the food source and to determine the offset in d15N between the coral tissue and its diet. The starvation trial culture experiment was conducted to evaluate the effects of starvation on the d15N of coral tissue. For both experiments coral tissue was analyzed using an EA-IRMS. This data also includes the d15N of the respective Artemia diets. Finally, included in this data is hydrological and particulate matter data collect at the site the corals were collected (near Friday Harbor, WA). This data includes nitrate d15N and d18O, suspended particulate organic matter d15N, net tow material d15N, and data collected from a CTD profiler. This data enhances the understanding of cold-water coral diet and trophic position. This data improves the understanding of the relationship between surface nitrate d15N and the d15N recorded in the coral skeleton which is useful for enhancing the resolution of coral d15N paleoproxies.


Coverage

Location: Off the coast of Friday Harbor, WA in the San Juan Islands, 0-45m depth.
Spatial Extent: N:48.598 E:-122.935 S:48.544 W:-123.016
Temporal Extent: 2019-03-31 - 2022-05-23

Dataset Description

See "Related Datasets" section on this page to access data and metadata for datasets collected as part of the same study.


Methods & Sampling

This methodology section describes this dataset and other closely related datasets collected as part of this study (see "Related Datasets").

Corals (Balanophyllia elegans, LSID=urn:lsid:marinespecies.org:taxname:286920) were collected by divers using blunt-tipped diving knives to remove corals from vertical rock walls at 10-20 m depths. A subset of the corals were immediately frozen for determination of N isotope ratios of tissue and skeleton. Another subset of corals were shipped live overnight to St. Olaf College for the culture experiments. 

For the culture experiment, corals were divided into four groups that were each fed Artemia  (LSID=urn:lsid:marinespecies.org:taxname:480245) nauplii with a different known d15N. The coral tissue was sampled at discrete intervals over the course of the experiment as described below. 

For the starvation experiment, corals were split into two group, starved and unstarved. The starved group was fed once every two weeks and the unstarved corals were fed twice a week. The coral tissue was sampled at discrete intervals throughouth the experiment as described below. 

 

Once separated from the skeleton, coral tissue was lyophilized and analyzed using a Costech Elemental Analyzer Isotope Ratio Mass Spectrometer. 

Once separated from the coral tissue, the coral skeletons were rinsed and ultrasonicated two times in Milli-Q water, then ultrasonicated in 1% sodium hypochlorite in 20 minute intervals until no tissue remained on the skeleton. The skeletons were then prepared following the methods of Wang et al (2014). The skeleton was ground to a powder using a mortar and pestle, then rinsed with sodium hypochlorite to remove any remaining tissue. The skeletal materials were then dissolved with 4N hydrochloric acid, then oxidized to nitrate by autoclaving in a basic potassium persulfate solution. Skeletal material was oxidized in tandem with standards of glutamine reference material USGS-40 and USGS-41. The samples were then analyzed by Gas Chromatography- Isotope Ratio Mass Spectrometry using the denitrifier method (Sigman et al., 2001). In brief, the denitrifier method uses the denitfrying bacteria Pseudomonas chlororaphis f. sp. aureofaciens to convert nitrate to nitrous oxide. P. aureofaciens was grown in media amended with 10mM nitrate in stoppered glass bottles for 7-10 days before being harvested and resuspended in nitrate free media. Three milliliters of resuspended bacteria was allocated to 20mL headspace vials which were sparged with dinitrogen gas for 6 hours. Nitrate sample solutions were injected into vials (target of 20nmol nitrogen for seawater samples and 7nmol for skeletal matrix samples) and incubated overnight to allow for the complete conversation of nitrate to nitrous oxide. The nitrous oxide was extracted and purified using a Thermo Gas Bench II with a GC Pal autosampler and dual cold traps and analyzed on a Thermo Advantage continuous flow isotope ratio mass spectrometer. Analyzes were referenced to N2O injected from a pure gas cylinder and standardized through comparison potassium nitrate reference materials International Atomic Energy Agency Nitrate (IAEA-N3) and the isotopic nitrate reference material from the United States Geological Survey 34 (USGS-34).

Artemia nauplii samples were stored frozen then lyophilized prior to analysis on the Elemental Analyzer Isotope Ratio Mass Spectrometer. 

Nitrate samples were collected with Van-Doren Sampler and filtered with pre-combusted glass fiber filters (GF/F, 0.7uM nominal pore size). The nitrate concentrations were determined using reduction to nitrous oxide in hot vanadium III solution followed by chemiluminescence detection of nitrous oxide on a Teledyne chemiluminescence NOx analyzer Model T200. The nitrogen and oxygen isotopes of nitrate were analyzed with the denitrifier method on an IRMS (described above).

Suspended particulate organic matter was collected with a Van-Doren Sampler and then collected on pre-combusted GF/F. The filters were lyophilized prior to analysis on an EA-IRMS.

Net tow material was collected with plankton nets with mesh sizes ranging from 80uM, 120uM, and 150uM. The net tow material was filtered and collected on a pre-combusted GF/F which was lyophilized prior to analysis on the EA.

Hydrologic depth profiles were characterized with a CastAway-CTD profiler. 


Data Processing Description

Coral tissue and particulate matter was analyzed in tandem with the glutamine standards USGS-40 and USGS-41. These standards were used to correct the data from the EA-IRMS.

Coral skeleton material was oxidized in tandem with USGS-40 and USGS-41 which was used to correct for any oxidation blank. While IAEA-N3 and USGS-34 were used as standard material to correct the nitrate isotope data collected off the IRMS.

Data corrections were performed in Excel. The data reported here is averages of multiple runs when applicable. The uploaded data indicates when these are analytical replicates or sample replicates, all have n ≥ 2.


BCO-DMO Processing Description

* Sheet "Starvation Trial" of submitted file "BCO-DMO data.xlsx" was imported into the BCO-DMO data system for this dataset. Values "NA" were imported as missing data values. 
** Missing data values are displayed differently based on the file format you download.  They are blank in csv files, "NaN" in MatLab files, etc.
* Additional column d15N_flag added to indicate when a missing data value is because of below detection limit =BDL
* Column names adjusted to conform to BCO-DMO naming conventions designed to support broad re-use by a variety of research tools and scripting languages. [Only numbers, letters, and underscores.  Can not start with a number]

* Date converted to ISO 8601 format.


[ table of contents | back to top ]

Data Files

File
919993_v1_b-elegans-starvation-trial.csv
(Comma Separated Values (.csv), 2.00 KB)
MD5:5d49b99af9691d8da59397080afcaf52
Primary data file for dataset ID 919993, version 1

[ table of contents | back to top ]

Related Publications

Sigman, D. M., Casciotti, K. L., Andreani, M., Barford, C., Galanter, M., & Böhlke, J. K. (2001). A Bacterial Method for the Nitrogen Isotopic Analysis of Nitrate in Seawater and Freshwater. Analytical Chemistry, 73(17), 4145–4153. doi:10.1021/ac010088e
Methods

[ table of contents | back to top ]

Related Datasets

IsRelatedTo
Gothmann, A. M., Granger, J., Prokopenko, M. (2024) CTD data from casts at Friday Harbor, WA in August of 2021 as part of a study of cold-water coral Balanophyllia elegans diet and trophic position. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2024-02-09 doi:10.26008/1912/bco-dmo.920001.1 [view at BCO-DMO]
Relationship Description: Datasets collected as part of the same study scleractinian cold-water coral Balanophyllia elegans diet and trophic position at Friday Harbor, WA. Data was collected between March 2019 and August 2021.
Gothmann, A. M., Granger, J., Prokopenko, M. (2024) Data for Artemia fed to corals (Balanophyllia elegans) during a culture experiment conducted to evaluate the relationship between coral diet and tissue nitrogen isotopic ratio from 2019 to 2021. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2024-02-09 doi:10.26008/1912/bco-dmo.919977.1 [view at BCO-DMO]
Relationship Description: Datasets collected as part of the same study scleractinian cold-water coral Balanophyllia elegans diet and trophic position at Friday Harbor, WA. Data was collected between March 2019 and August 2021.
Gothmann, A. M., Granger, J., Prokopenko, M. (2024) Experimental data (coral diet and tissue d15N) from a culture experiment with scleractinian cold-water coral Balanophyllia elegans collected at Friday Harbor, WA from experiments conducted between 2019 and 2020. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2024-02-09 doi:10.26008/1912/bco-dmo.919969.1 [view at BCO-DMO]
Relationship Description: Datasets collected as part of the same study scleractinian cold-water coral Balanophyllia elegans diet and trophic position at Friday Harbor, WA. Data was collected between March 2019 and August 2021.
Gothmann, A. M., Granger, J., Prokopenko, M. (2024) Nitrogen isotope ratio data for coral tissue and skeleton samples of the scleractinian cold-water coral Balanophyllia elegans collected at Friday Harbor, WA from experiments conducted between 2019 and 2021. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2024-02-08 doi:10.26008/1912/bco-dmo.919958.1 [view at BCO-DMO]
Relationship Description: Datasets collected as part of the same study scleractinian cold-water coral Balanophyllia elegans diet and trophic position at Friday Harbor, WA. Data was collected between March 2019 and August 2021.
Gothmann, A. M., Granger, J., Prokopenko, M. (2024) Particulate data collected near Friday Harbor, WA between 2020 and 2021 as part of a study of cold-water coral Balanophyllia elegans diet and trophic position. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2024-02-09 doi:10.26008/1912/bco-dmo.919985.1 [view at BCO-DMO]
Relationship Description: Datasets collected as part of the same study scleractinian cold-water coral Balanophyllia elegans diet and trophic position at Friday Harbor, WA. Data was collected between March 2019 and August 2021.

[ table of contents | back to top ]

Parameters

ParameterDescriptionUnits
Sample_ID

Name given to identify each sample

unitless
Date_sampled

Date the coral was sacrificed for sampling

unitless
Experimental_condition

Condition of the coral sample in the starvation experiment, either Starved or Not Starved, or the initial condition before the start of the experiment

unitless
Day_of_experiment

Number of days since the start of the experiment when the individual coral was sampled

days
d15N

Nitrogen isotopic ratio d15N

permil (0/00)
d15N_flag

flag for the d15N column. If value is BDL it indicates the d15N value is blank because it was "below detection limit"

unitless
d15N_stdev

Standard deviation of d15N when more than one measurement was taken

permil (0/00)
d13C

Carbon isotopic ratio d13C

permil (0/00)
d13C_stdev

Standard deviation of d13C when more than one measurement was taken

permil (0/00)


[ table of contents | back to top ]

Instruments

Dataset-specific Instrument Name
Costech Elemental Analyzer Isotope Ratio Mass Spectrometer
Generic Instrument Name
Mass Spectrometer
Generic Instrument Description
General term for instruments used to measure the mass-to-charge ratio of ions; generally used to find the composition of a sample by generating a mass spectrum representing the masses of sample components.


[ table of contents | back to top ]

Project Information

Collaborative Research: Refining the use of scleractinian cold-water coral skeleton-bound d15N as a proxy for marine N cycling (Coral-bound N)

Coverage: Global ocean


NSF abstract:

Refining the use of scleractinian cold-water coral skeleton-bound d15N as a proxy for marine N cycling

Recent studies show that cold-water corals and their skeletons provide valuable information about the marine nitrogen (N) cycle. This information can shed light on the processes that both drive and respond to changes in Earth’s climate. Cold-water corals are found across the global ocean and can be dated with decadal precision, offering spatial and temporal records of the N cycle in the past. In addition, a single skeleton can be used to reconstruct both surface and deep ocean composition. Despite the promise of cold-water corals, we don’t fully understand how they record changes in the marine N cycle. We must strengthen this understanding before we use cold-water corals to produce reliable records of marine N cycling across space and time, across different coral species, and under different lifestyle and feeding patterns. This project examines how the isotopic composition of organic N trapped in coral skeletons is linked to marine N cycle properties. The study includes a series of lab experiments, measurements of live corals sampled from the natural environment, and measurements of coral skeletal material from different ocean regions and depth horizons archived in museums. The project involves undergraduates at St. Olaf College, Pomona College and Mt. San Antonio College, one of the largest community colleges in Southern California. These students will conduct the research with scientists and peers in collaborating labs. Participation in the project will build student research skills and scientific knowledge for advanced study and prepare students for the scientific workforce. The project will also develop educational materials, including YouTube videos, to promote interest in marine science and awareness of how climate change influences global oceans. These educational materials will be created in collaboration with high school students from underrepresented groups.

The main tool used to investigate marine N cycle history is the isotope composition of particulate organic nitrogen (δ15N-PON) exported from the euphotic zone, which can be accessed using sedimentary archives such as foraminiferal tests, anoxic sediments and soft corals. Recently, the δ15N of organic N trapped within asymbiotic scleractinian cold-water coral (CWC) skeletons has been shown to record the δ15N-PON exported from the surface ocean (Wang et al. 2014; Wang et al. 2017). In order to reliably apply CWC δ15N as a proxy, however, we must explain a ~8.5‰ offset between the δ15N of organic nitrogen within the CWC skeleton and the exported δ15N-PON in regions of coral growth (Wang et al. 2014). The nature of the δ15N offset must be accounted for to be confident that CWC records marine N cycle history consistently across space and time, across different coral species, and for corals with different lifestyle conditions. Through coral culture experiments, measurements of live corals samples from the natural environment, and archives of corals skeletal material from different ocean regions and depth horizons, this research will test whether the offset arises from: (1) a biosynthetic isotope offset between CWC tissue and skeleton, (2) an unusual trophic transfer between CWC tissue and diet, and/or (3) coral feeding on material with elevated δ15N relative to exported δ15N-PON. This work will also provide estimates of N turnover time in CWC, which are scant, and will inform trophic ecology of CWC.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.



[ table of contents | back to top ]

Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

[ table of contents | back to top ]