Document Type

Article

Publication Date

11-28-2012

Publication Title

PLoS One

Keywords

Food web structure, Marine fish, Marine ecosystems, Isotope analysis, Amino acid analysis, Ecosystems, Biogeochemistry, Predation

ISSN

1932-6203

Volume

7

Issue/No.

11 e50133

First Page

1

Last Page

8

Abstract

The δ15N values of organisms are commonly used across diverse ecosystems to estimate trophic position and infer trophic connectivity. We undertook a novel cross-basin comparison of trophic position in two ecologically well-characterized and different groups of dominant mid-water fish consumers using amino acid nitrogen isotope compositions. We found that trophic positions estimated from the δ15N values of individual amino acids are nearly uniform within both families of these fishes across five global regions despite great variability in bulk tissue δ15N values. Regional differences in the δ15N values of phenylalanine confirmed that bulk tissue δ15N values reflect region-specific water mass biogeochemistry controlling δ15N values at the base of the food web. Trophic positions calculated from amino acid isotopic analyses (AA-TP) for lanternfishes (family Myctophidae) (AA-TP ,2.9) largely align with expectations from stomach content studies (TP ,3.2), while AA-TPs for dragonfishes (family Stomiidae) (AA-TP ,3.2) were lower than TPs derived from stomach content studies (TP,4.1). We demonstrate that amino acid nitrogen isotope analysis can overcome shortcomings of bulk tissue isotope analysis across biogeochemically distinct systems to provide globally comparative information regarding marine food web structure.

Comments

This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

Additional Comments

NSF grant #s: OCE-1041329, OCE-0623551; Pelagic Fisheries Research Program cooperative agreement #: NA17RJ123; Department of the Interior U.S.G.S. cooperative agreement #s: 05HQAG0009, subagreements 05099HS004, 5099HS0013

ORCID ID

0000-0002-5280-7071

DOI

10.1371/journal.pone.0050133

Peer Reviewed

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