DOI: 10.5061/dryad.zw3r22897
title: Amino acid d13C dataset for nearshore marine primary producers

description: Carbon isotope fingerprinting, or multivariate analysis using δ13C values
 of individual compounds, is a powerful tool in ecological studies,
 particularly measurements of essential amino acids (EAA δ13C). Despite the
 widespread application of this technique, there has been little
 methodological validation to determine (1) whether multivariate EAA δ13C
 signatures (fingerprints) of primary producer groups vary across space and
 time, and (2) what biochemical mechanisms drive these patterns. Here, we
 evaluate the spatiotemporal consistency in EAA δ13C fingerprints among
 nearshore primary producers: Chlorophyta (Ulva sp.), Ochrophyta (kelps),
 particulate organic matter (POM) and phytoplankton, and Rhodophyta. We
 analyzed 135 samples from 14 genera collected in Alaska, California, and
 Chile. The collections included historical museum samples (1896-1980 CE)
 of the giant kelp, Macrocystis pyrifera. We employed canonical analysis of
 principal coordinates and generalized linear models (GLMs) to respectively
 characterize isotopic fingerprints and evaluate the effect of taxonomy,
 local upwelling regimes, ecological setting, and time on individual EAA
 δ13C values and associated fingerprints. We also calculated amino acid
 discrimination values (D13C) to identify key biochemical pathways
 responsible for these patterns. We found remarkable consistency in EAA
 δ13C fingerprints of marine algae across space and through time. Kelps and
 rhodophytes exhibited statistically distinct multivariate isotopic
 patterns regardless of geographic location, species identity, or time
 (kelps). In contrast, isotopic fingerprints of POM/phytoplankton and Ulva
 overlapped substantially. GLMs indicated that producer family, presumably
 due to the presence/absence of carbon concentrating mechanisms, and site
 locality are important determinants of individual amino acid δ13C values.
 Taxonomy was also a key variable for EAA δ13C fingerprints. The calculated
 discrimination values suggest variation in (1) metabolism of pyruvate and
 oxaloacetate-derived amino acids, and (2) production of storage and
 structural carbohydrates, are responsible for taxonomic differences in
 isotopic fingerprints.  We conclude EAA δ13C fingerprinting is a
 robust method for tracing the contribution of diverse primary producer
 taxa to coastal food webs. We show that this technique can be applied to
 modern and historical samples, as well as consumers collected across
 continental scales. The high fidelity of EAA δ13C multivariate patterns
 coupled with biochemical mechanisms provides a powerful framework for
 future studies of carbon flow across broad biogeographical and ecological
 contexts.
description: Taxonomic designations (e.g., Family and Phylum) come from
 AlgaeBase, as accessed in March 2021. Column 'CCMs' deontes the
 presence (Y), or absence (N), of carbon concentrating mechanisms in a
 given taxa. Column 'Ocea' denotes the general oceanography of a
 region, including downwelling (Down), seasonal upwelling (SeasUp), and
 consistent upwelling (ConsUp), as well as laboratory cultures (Cultured).
 Column 'Time' indiactes whether samples are modern, or come from
 the Smithsonian Insitituion NMNH Botany Collections. The cataloge number
 for NMNH samples and the associated year of collection can be found in the
 column 'ID'; for example, sample
 'NMNH-71452-MAPY-1896-Bl", comes from NMNH Macrocystis specimen
 71452 whichwas collected in CE 1896. Empty cells (e.g.,
 missing values) represent data that were not determined for a particular
 isptopic measurement and sample.