***Reconstructing the diet, trophic level, and migration pattern of Mysticete whales based on baleen isotopic composition.

Philip M. Riekenberg1*, Jaime Camalich1, Elisabeth Svensson1, Lonneke L. IJsseldijk2, Sophie M.J.M. Brasseur3, Rob Witbaard4, Mardik F. Leopold3, Elisa Bravo Rebolledo3,6, Jack J. Middelburg5, Marcel T.J. van der Meer1,  Jaap S. Sinninghe Damsté1,5, Stefan Schouten1,5
(1) Department of Marine Microbiology & Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, Den Hoorn, 1790AB, The Netherlands
(2) Division of Pathology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3854 CL, Utrecht, The Netherlands
(3) Wageningen Marine Research, Wageningen University and Research, PO Box 57, 1780 AB, Den Helder, The Netherlands 
(4) Department of Estuarine and Delta Systems, NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University, PO Box 140, 4400 AC, Yerseke, The Netherlands
(5) Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Princetonlaan 8a, 3584 CB, Utrecht, The Netherlands
(6) Current: Bureau Waardenburg, Department of Bird Ecology, 4101 CK Culemborg, The Netherlands

*Corresponding Author: PMR, phrieken@gmail.com

***General Introduction***
This data set contains the  nitrogen stable isotope values from amino acids contained in the baleen from whales stranded or bowcaught in the North Sea as described in the manuscript

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


***Test Equipment***
Drilled baleen powder samples were loaded into tin capsules for Bulk-SIA analysis using a Delta V Advantage Isotope ratio mass spectrometer with a Flash 2000 Organic Element Analyzer (Thermo Fisher Scientific). 
The reference materials acetanilide (Biogeochemical Laboratories at Indiana University), urea, and casein (Microanalysis Ltd., Okehampton, UK) were standards for stable isotope measurements for δ13C 
and δ15N expressed as per mil (‰) differences from the δ13C value of Vienna Peedee-Belemnite Limestone (VPDB) and the δ15N value of atmospheric N2. Sample precision was ±0.1‰ and ±0.2‰ for δ13C 
and δ15N, respectively, for bulk materials supporting this study.   

***Description of data***
lab; laboratory that analyzed the sample
lab_sample_id; lab sample ID
mm_length__from_gum; mm length of baleen sample was taken from measured from the gum
sample_measurement_id; Bulk analysis of C and N 
collected_sample_mass; sample weight
instrumentation; Elemental analyzer
analysis_type; Bulk analysis of solid material
analysis_date; date and month of analysis
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
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
collection_locality; Wadden or North Sea
taxon_rank; ID is to species level
scientific_name; Genus species
%C; percent  carbon
%N; percent nitrogen
d13C; delta 13 C in per mille
d13C_measurement_scale; against Vienna PeeDee Belemnite
d13C_measurement_unit; per mille
d15N; delta 15N in per mille
d15N_measurement_scale; against atmospheric N2
d15N_measurement_unit; per mille
