Paired bulk organic and individual amino acid δ15N analyses of bivalve shell periostracum: A paleoceanographic proxy for water source variability and nitrogen cycling processes

dc.contributor.author Whitney, Nina
dc.contributor.author Wanamaker, Alan
dc.contributor.author Johnson, Beverly
dc.contributor.author Dotsie, Philip
dc.contributor.author Luzier, Katherine
dc.contributor.author Wanamaker, Alan
dc.contributor.department Geological and Atmospheric Sciences
dc.date 2019-05-17T06:19:17.000
dc.date.accessioned 2020-06-30T04:04:23Z
dc.date.available 2020-06-30T04:04:23Z
dc.date.copyright Tue Jan 01 00:00:00 UTC 2019
dc.date.embargo 2020-03-27
dc.date.issued 2019-03-27
dc.description.abstract <p><p id="x-x-x-x-x-sp0005">Developing high resolution, well-dated marine proxies of environmental, climatic, and oceanographic conditions is critical in order to advance our understanding of the ocean’s role in the global climate system. While some work has investigated bulk and compound specific stable nitrogen isotopes (δ15N) in bivalve shells as proxies for environmental variability, the small concentrations of nitrogen found in the organic matrix of the shell calcium carbonate (CaCO3) makes developing high resolution records challenging. This study investigates the potential of using the bulk and amino acid δ15N of bivalve periostracum, the protein layer on the outside of the shell, as a proxy archive of nitrogen cycling processes and water source variability.</p> <p>Bulk δ15N values were measured on the periostracum, aragonitic CaCO3, and adductor muscle of <em>Arctica islandica</em>shells collected in the Gulf of Maine. Increased variability of isotopic values across growth lines compared to along growth lines support mechanistic reasoning based on growth processes that periostracum is recording changes in δ15N over the course of the clam’s lifetime (up to 500 years). In addition, the statistically significant relationship between periostracum δ15N and contemporaneous carbonate δ15N of the same shell (r= 0.82, p</p> <p>Compound specific δ15N analyses of the periostracum of <em>A. islandica</em> shells were used to determine that the calculated trophic position of the clams in this study (1.4±0.4) did not change significantly between 1783 and 1997. Phenylalanine δ15N values over the last 70 years show similar trends to that of the bulk record, suggesting that changes in bulk δ15N of that time period are related to changes in baseline δ15N. Periostracum δ15N values from shells collected in the western Gulf of Maine have decreased by ∼1‰ since the mid-1920s. This trend (-0.008‰/year) is not statistically different from the trend of previously published δ15N values of deep-sea corals from the entrance to the Gulf of Maine over the same time period. This coral record has been shown to indicate a shift in water mass source to the region and therefore the similarity between the two records suggest that changes in periostracum δ15N values are reflecting broader North Atlantic hydrographic changes. Our study introduces a new, high-resolution and absolutely dated paleoceanographic proxy of baseline δ15N, presenting the opportunity for future reconstructions of aspects of nitrogen cycling and water source changes in the global oceans.</p>
dc.description.comments <p>This is a manuscript of an article published as Whitney, Nina M., Beverly J. Johnson, Philip T. Dostie, Katherine Luzier, and Alan D. Wanamaker Jr. "Paired bulk organic and individual amino acid δ15N analyses of bivalve shell periostracum: A paleoceanographic proxy for water source variability and nitrogen cycling processes." <em>Geochimica et Cosmochimica Acta</em> (2019). doi: <a href="https://doi.org/10.1016/j.gca.2019.03.019" target="_blank" title="Persistent link using digital object identifier">10.1016/j.gca.2019.03.019</a>. Posted with permission.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/ge_at_pubs/266/
dc.identifier.articleid 1276
dc.identifier.contextkey 14172134
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath ge_at_pubs/266
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/38210
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/ge_at_pubs/266/2019_Wanamaker_PairedBulkManuscript.pdf|||Fri Jan 14 23:03:35 UTC 2022
dc.source.uri 10.1016/j.gca.2019.03.019
dc.subject.disciplines Climate
dc.subject.disciplines Cosmochemistry
dc.subject.disciplines Environmental Sciences
dc.subject.disciplines Oceanography
dc.subject.disciplines Paleontology
dc.subject.keywords δ15Namino acids
dc.subject.keywords Arctica islandica
dc.subject.keywords paleoclimate
dc.subject.keywords ocean circulation
dc.title Paired bulk organic and individual amino acid δ15N analyses of bivalve shell periostracum: A paleoceanographic proxy for water source variability and nitrogen cycling processes
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 0888f196-5404-41d6-a609-1ab839a739c6
relation.isOrgUnitOfPublication 29272786-4c4a-4d63-98d6-e7b6d6730c45
File
Original bundle
Now showing 1 - 1 of 1
Name:
2019_Wanamaker_PairedBulkManuscript.pdf
Size:
2.49 MB
Format:
Adobe Portable Document Format
Description:
Collections