Table of Contents

• Dataset Description
  • Methods & Sampling
• Data Files
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Project Information
• Funding

This dataset includes the following files, packaged in a .zip file:

• archived_pca_spectra.zip = unprocessed ¹H NMR spectral data files underlying PCA analysis in the publication "Chemical encoding of risk perception and predator detection among estuarine invertebrates."
• archived_pls-r_spectra.zip = unprocessed ¹H NMR spectral data files underlying PLS-R analysis in the publication "Chemical encoding of risk perception and predator detection among estuarine invertebrates."
• README_ArchivedSpectraDataset (1).doc = readme file describing the files.
• spectral_labels_for_pls-r_dataset.xlsx = spreadsheet containing spectral labels.

Poulin et al (2018) contains the analyses of the processed data. These NMR data files are also available from the Georgia Tech database, SMARTech at http://hdl.handle.net/1853/59056

1H NMR spectra were processed in MATLAB, version 8.1.0.604, using NMRLab. Spectra were manually phased, baseline corrected, aligned, and the following regions excluded to remove contaminants from statistical analysis: TMSP (-0.5 to 0.5 ppm), water (4.6-5.2 ppm), residual methanol (3.2-3.4 ppm), and excess area (9.0-12.4 ppm) that contained no spectroscopic features. Spectroscopic features were clustered into 0.005 ppm bins, probabilistic quotient normalized to remove dilution bias, and generalized log (glog) transformed to avoid bias towards high concentration metabolites without affecting between-sample variation. Glog optimization values, λ, were generated from five technical replicates that consisted of equal parts from a single bulk urine sample using the methods above. For urine samples collected at Skidaway Institute of Oceanography, λ = 2.9359×10-7 and for urine samples at Georgia Tech λ = 8.2585×10-9.

Extracted from the NSF award abstract:

In this project, the investigators will examine the ability of top blue crab predators to indirectly benefit the abundance of basal oyster prey by reducing the density (consumptive effects, CEs) and suppressing foraging (non-consumptive effects, NCEs) of intermediate mud crab predators. These NCEs are mediated by chemical perception of aversive cues in blue crab urine and produce a behaviorally mediated trophic cascade. Through a series of manipulative experiments, the investigators will examine how the strength of this behaviorally-mediated trophic cascade is modulated and factors that influence perceptive range such as predator diet and intake rate, and the flow environment. The investigators will also determine the chemical identity, concentration and release rate of chemical cues.

Identifying the quantitative and molecular aspects of aversive cues, and linking them to behavioral responses that produce trophic cascades establishes the chemical basis of risk perception by prey and how this translates into cascading ecological effects. The use of perceptive range as a framework for evaluating the effects of both chemistry and environment provides an integrated view of processes affecting chemically-mediated NCEs. The use of a water borne predator-prey signaling system to test ideas on the strength of NCEs should have broad applications.