Poster Presentation Society for Freshwater Science 2025 Annual Meeting

STOICH: A new global database of organismal stoichiometry, with applications for aquatic invertebrates (117808)

Halvor M. Halvorson 1 , Casey Brucker 2 , Sarah Collins 2 , Molly Costanza-Robinson 3 , J. Harrison Edwards 2 , Elise Ehlers 2 , W. Reilly Farrell 4 , Amy Krist 2 , Erin Larson 5 , Eric Moody 3 , Mark Nessel 6 , Chad Petersen 4 , Linnea A. Rock 2 , Steve Thomas 7 , Benjamin Tumolo 2 , Catherine Wagner 2 , Binbin Wang 4 , Tekin Yilmaz 4 , Jessica Corman 4
  1. University of Central Arkansas, Conway, AR, United States
  2. University of Wyoming, Laramie
  3. Middlebury College, Middlebury
  4. University of Nebraska, Lincoln
  5. University of Alaska at Anchorage, Anchorage
  6. Oklahoma State University, Stillwater
  7. University of Alabama, Tuscaloosa

All organisms contain carbon (C), nitrogen (N), and phosphorus (P) in widely varying amounts and proportions. There is a need to integrate existing organismal elemental datasets to quantify and constrain this variation at global scales. Such efforts could leverage ecological stoichiometry to connect drivers such as space, time, and community structure to ecosystem structure and function. We developed the STOICH (Stoichiometric Traits of Organisms In their Chemical Habitats) database to investigate broad-scale patterns in ecological stoichiometry, with a focus on field datasets from inland aquatic ecosystems. Here, we will summarize the status of the STOICH database and provide an application for aquatic invertebrates. This growing database includes >31,000 observations of organismal elemental contents from >2,300 sites, derived from >136 sources. Applying the database to aquatic invertebrates, we explored variation of molar C:N and C:P ratios across and within taxonomic Families, and we compared whether patterns differed between raw vs. log10-transformed ratios. We calculated global means and coefficients of variation (CVs) for all taxonomic Family groups where sample sizes were 10 or greater (n=90 Families for C:N, and n=37 Families for C:P). For raw C:N, the global Family-level mean C:N was 5.7 (range=3.9-8.0) and the average Family-level CV was 18.7% (range=3.6%-71.9%). For log-C:N, the mean C:N was similar at 5.5 (range=3.9-7.4) and the average CV was cut in half to 9.6% (range=2.1%-25.5%). For raw C:P, the mean C:P was 217 (range=33-585) and average CV was 41.4% (range=9.1%-111.4%). For log-C:P, the mean C:P was reduced to 174 (range=33-487) and the average CV was cut by more than four-fold to 7.5% (range=2.5%-12.0%). These data suggest that log-transformation can substantially reduce within-Family variation of elemental ratios, and molar C:N and C:P ratios exhibit relatively similar CVs globally, after such transformation. Our findings leverage STOICH to quantify global stoichiometric traits across aquatic invertebrates; if sufficiently representative and constrained, these traits warrant many further applications.