*** Compound-specific stable isotope analysis of amino acid nitrogen reveals detrital support of microphytobenthos in the Dutch Wadden Sea benthic food web***

Authors: Philip Riekenberg1*+,  Tjisse van der Heide2,3, Sander J. Holthuijsen2, Henk W. van der Veer2, and Marcel T.J. van der Meer1 

(1) Department of Marine Microbiology & Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 1790AB Den Burg Texel, The Netherlands
(2) Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 1790AB Den Burg Texel, The Netherlands
(3) Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9700 CC, Groningen, The Netherlands

Corresponsding Author: P. Riekenberg phrieken@gmail.com

***General Introduction***
This data set contains the  nitrogen stable isotope values from amino acids contained in a subset of the SIBES sampling campaigns from 2011 to 2014 in the Dutch Wadden Sea.

The data in this manuscript was produced in the Stable Isotope Laboratory in the Marine Microbiology and Biogeochemistry Department at NIOZ. 

***Test Equipment***
For compound specific isotope analysis of amino acid nitrogen, dried and homogenized tissue (2-5 mg) was lipid extracted, acid hydrolyzed, derivatized to pivaloyl- isopropyl esters and analysed for δ15N of AAs via gas 
chromatography-combustion isotope mass spectrometry using a Thermo Trace 1310 GC attached to Delta V Advantage isotope ratio mass spectrometer via an Isolink 2 following the method presented in Riekenberg, et al. (2020). 
δ15N values for the amino acids glutamic acid + glutamine (Glu) and phenylalanine (Phe) are presented.  Precision of amino acid δ15N values were <=1‰ in standards run throughout the analytical runs supporting this study 
and samples were analyzed in duplicate. Normalization using two standard reference mixtures along with a reference spike of norleucine (Nle) added to all samples and standards which served as an internal reference 
calibration following the method from Yarnes and Herszage (2017).  

***Description of data***
lab; laboratory that analyzed the sample
user_sample_id; User sample ID
instrumentation; Elemental analyzer
analysis_type; compound specific analysis for d15N of amino acids
client_id; Who owns the sample
analytical_matrix; all tissues in this data set
primary_reference_material; Primary isotope reference material
preparation_step; sample preparations
preparation_step; sample preparations
derivatization form; pathway used for preparation of amino acids
material_type; generalized categories for sample ID of tissues
material_sample_id; Exact sample ID for tissue types
collection_source; All field samples
investigator_name; Philip Riekenberg
investigator_orcid; 0000-0002-6275-5762
investigator_email; phrieken@gmail.com
decimal degrees east; sampling location 
decimal degrees north; sampling location
collection_locality; Wadden Sea
taxon_rank; ID is to genus or species level
scientific_name; Genus species
amino acid_d15N; delta 15 N value for each amino acid
amino acid_error; standard deviation for the sample replicates of each amino acid
d15N_measurement_scale; against atmospheric N2
d15N_measurement_unit; per mille
d15N_error; standard deviation of the sample replicates for each amino acid analysis



