DOI: 10.5061/dryad.2fqz61326
title: Supporting isotopic data for: Differential utilization of submerged leaf litter by microbial biofilms and macroinvertebrates in a large dryland river

description: In river food webs, the energetic coupling of nutrient-rich ‘fast’
 autochthonous (algal) and recalcitrant ‘slow’ allochthonous (terrestrial)
 resources may confer stability. Additionally, microbial biofilms may
 enhance the nutritional quality of allochthonous resources for
 macroinvertebrate consumers, potentially facilitating trophic linkages
 within slow energy channels. We used 16S and 18S rRNA gene sequencing and
 essential amino acid (AAESS) carbon isotope (δ13C) analysis to
 characterize microbial biofilms and quantify proportional contributions of
 AAESS derived from algae, terrestrial plants, and microbes (Archaea,
 Bacteria, fungi) to macroinvertebrates across a series of mesocosm and in
 situ leaf pack experiments in the middle Rio Grande of central
 New Mexico, USA. In our 12-week mesocosm experiment, we found that leaves
 of native Rio Grande Cottonwood trees (Populus deltoides wislizeni)
 contributed greater mean estimated proportions of AAESS (0.41–0.81) to
 Chironomidae larvae than those of nonnative Russian Olive trees (Elaeagnus
 angustifolia; 0.18–0.50). Microbes were notable sources of AAESS to
 macroinvertebrates inhabiting native C4 grass (Spike Dropseed; Sporobolus
 contractus) leaf packs (0.08–0.26). Our field experiment demonstrated
 river sediment was the main source of microbes colonizing submerged
 Cottonwood leaves and that allochthonous resource use varied across
 macroinvertebrate taxa, such that Chironomidae assimilated the highest
 mean estimated proportions of AAESS from Cottonwood leaves (0.36–0.65)
 while Ephemeroptera and Trichoptera assimilated the highest mean estimated
 proportions of AAESS from algae (0.82–0.94). Our work indicates
 terrestrial tree leaves are important sources of AAESS to Chironomidae,
 while algae are the dominant source of AAESS to other macroinvertebrates
 in the middle Rio Grande.
description: # Supporting isotopic data for: Differential utilization of submerged leaf
 litter by microbial biofilms and macroinvertebrates in a large dryland
 river **Alexi C. Besser** Dataset DOI:
 [10.5061/dryad.2fqz61326](10.5061/dryad.2fqz61326) ## Description of the
 data and file structure Stable carbon isotope values of individual amino
 acids were measured via gas chromatography-combustion-isotope ratio mass
 spectrometry after derivatization to N-trifluoroacetic acid isopropyl
 esters at the University of New Mexico Center for Stable Isotopes. Stable
 carbon isotope values are expressed in delta notation (delta = [(Rsample –
 Rreference)/Rreference], where R = the ratio of 13C to 12C) and reported
 in parts per thousand (i.e., per mil). The international reference
 standard for stable carbon isotope analysis is Vienna Pee Dee Belemnite
 (VPDB). Additional information on sample collection, preparation,
 analysis, and data correction can be found in the accompanying manuscript
 and supporting information. ### Files and variables #### File:
 Besser_et_al_L_O_2025_AA_d13C_Data.csv **Description:**  ##### Variables *
 SampleID: unique identifier of sample * Group: sample type and broad
 functional group * Taxon: taxonomic identity of sample  * Experiment:
 experiment type  * SampleDate: date of sample collection * SampleLocation:
 location of sample collection * City: city of sample collection * County:
 county of sample collection * State: state of sample collection * Country:
 country of sample collection * Ala d13C: alanine stable carbon isotope
 value * Gly d13C: glycine stable carbon isotope value * Thr d13C:
 threonine stable carbon isotope value * Ser d13C: serine stable carbon
 isotope value * Val d13C: valine stable carbon isotope value * Leu d13C:
 leucine stable carbon isotope value * Ile d13C: isoleucine stable carbon
 isotope value * Pro d13C: proline stable carbon isotope value * Asx d13C:
 asparagine/aspartic acid stable carbon isotope value * Glx d13C:
 glutamine/glutamic acid stable carbon isotope value * Phe d13C:
 phenylalanine stable carbon isotope value * Tyr d13C: tyrosine stable
 carbon isotope value * Lys d13C: lysine stable carbon isotope value * Arg
 d13C: arginine stable carbon isotope value