Preparation and Distribution of DOC Consensus Reference Materials 2025-2028

Dissolved organic carbon (DOC) is a key component of the ocean’s carbon system. DOC plays an important role in the cycling of organic matter and the functioning of marine ecosystems. It is essential that DOC measurements be accurate and comparable across labs to understand how carbon is produced, transformed, and transported through the ocean. The consensus reference material (CRM) program has provided the international research community with calibration standards since 1998. These materials improve the reliability of DOC data across laboratories and regions. This project will support the DOC CRM Program for three more years. The Program will produce and distribute reference waters collected from surface, mid-depth, and deep layers of the Florida Strait to over 300 laboratories in more than 50 countries. These reference materials provide consistency to the measurements that contribute to global DOC datasets being used to examine spatial and temporal variability in the ocean. To further build analytical capacity across the community, the project also distributes DOC-TN Determination Kits. These kits include all necessary calibration and reference materials, along with guidelines for measuring DOC and total nitrogen (TN). These efforts enable high-quality data collection, support open and reproducible science, and promote the advancement of ocean observation on a global scale. The project also provides training for the next generation of DOC analysts. The project involves the annual collection of seawater from three depths in the Florida Strait, which is filtered, sealed in vials, and distributed internationally. A low-carbon reference water is also prepared to support calibrations across a range of concentrations. On average, 11,000 vials are distributed each year. These reference materials provide a stable benchmark for DOC analysis, enabling inter-laboratory consistency and improving the accuracy and reproducibility of data collected across platforms and time periods. Without access to standardized materials, researchers face challenges in verifying results and maintaining compatibility with existing datasets. The continuation of this program ensures that new DOC measurements remain aligned with long-term records, preserving the integrity of multi-year and multi-institutional studies. The DOC-TN Determination Kits, developed in a previous award cycle, will continue to be distributed as part of this effort. Each kit contains four calibration standards for carbon and nitrogen, four reference materials (surface, mid, deep, and low-carbon), and an Excel-based template that guides users through a structured analysis. Aligned with published community guidelines, these kits are especially useful for laboratories developing or refining their analytical capabilities. By ensuring access to high-quality reference materials and standardized procedures, the project continues to support the generation of globally comparable DOC and TN data and strengthens the foundation for collaborative ocean biogeochemistry research. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.