Stable Isotope Sample Analysis

Background
The U.S. Geological Survey (USGS) Florence Bascom Geoscience Center in Reston, Virginia, requires stable isotope analysis of carbonate microfossils to support scientific research on paleo-perspectives regarding hazards and ecosystem changes. The goal of this contract is to analyze samples to reconstruct changes in global ice volume, ocean temperature, circulation, and salinity. This work will contribute to multiple peer-reviewed research manuscripts.

Work Details
The contractor will conduct stable isotope analysis of 12C/13C and 18O/16O ratios on carbonate microfossil samples, primarily benthic foraminifera and ostracodes. The tasks include:

1. Sample Preparation: Weighing individual shells/tests on a microbalance, sorting into vials by mass, rinsing in methanol, drying at 50-60°C for 24 hours, and capping vials before analysis. Detailed methodologies must be provided to USGS after each call order.

2. Standards: Sorting Carrara marble standards matching the sample mass range for analytical runs.

3. Analysis: Conducting analyses with appropriate mass-groupings using an isotope ratio mass spectrometer with precision better than 0.060‰ for δ13C and 0.080‰ for δ18O. Sample preparation and analysis must occur within six months of receiving samples unless otherwise agreed due to unforeseen circumstances.

Deliverables include corrected δ13C and δ18O values in per mil VPDB along with corresponding isotope ratios, analytical uncertainties, error correlations, and signal intensity data.

Period of Performance
The contract will be performed over a one-year period after award with a maximum of 2,000 analyses expected to be completed prior to September 30, 2027.

Place of Performance
Reston, Virginia

Bidder Requirements
Bidders must have the capability to conduct stable isotope analysis on carbonate microfossils with documented analytical precision for samples in the size range of 5-150µg. The contractor's mass spectrometer must generate reliable data within this size range.