About

The Stable Isotope Facility (SIF) will be closing, effective July 26, 2026.

June 3, 2026
An Update on the Plant Sciences Stable Isotope Facility

Dear Faculty, Staff, Students, and Supporters,
After a lengthy review process and careful consideration, we have made the difficult decision to sunset the Stable Isotope Facility (SIF) in its current form, effective July 26, 2026.

The Department of Plant Sciences continues to face hard decisions surrounding funding allocation given the campus-wide request to reduce budgets. Over the past several years SIF has been operating with a significant and growing deficit and, despite extensive efforts over the last several months to find a solution that would allow the facility to continue to provide services to the research community, we have not found a model that is financially sustainable.

I want to thank SIF’s staff for their excellent work and dedication these past 25 years, and everyone who has played a role in supporting this facility.

We are committed to doing our best to support the researchers who rely on the facility during this transition, and will be in touch with individual clients about details of specific plans for handling existing orders over the next several weeks.

Sincerely,
Daniel Potter
Professor and Chair, Department of Plant Sciences
University of California, Davis

Original Letter

Returning SIF Samples (Facility closes July 26, 2026)

Dear Valued Client,

After a lengthy review process and careful consideration, we have made the difficult decision to sunset the Stable Isotope Facility (SIF) in its current form, effective July 26, 2026.

The Department of Plant Sciences continues to face hard decisions surrounding funding allocation given the campus-wide request to reduce budgets. Over the past several years, SIF has been operating with a significant and growing deficit and, despite extensive efforts over the last several months to find a solution that would allow the facility to continue to provide services to the research community, we have not found a model that is financially sustainable.

We regret to inform you that SIF staff will be unable to process your submitted samples before the facility's closure date. As a result, we would like to offer the option of returning your samples. If you would like your samples returned, please submit the request via return form on the SIF website. If you do not wish to have the samples returned, please notify us, and we will arrange for their appropriate disposal in accordance with established protocols.

We sincerely appreciate your support of the Stable Isotope Facility and the opportunity to have served your research needs.

Sincerely,
Daniel Potter
Professor and Chair, Department of Plant Sciences
University of California, Davis

Dr. David Harris founded the Stable Isotope Facility at the University of California, Davis in 1997. Since then the facility has grown to support well over 190,000 analyses annually from academic, governmental, and private clients in California and from around the world. To meet this demand, the SIF now employs twelve full-time staff, including three PhD-level academic staff. Currently, the SIF houses 14 isotope-ratio mass spectrometers and a cavity ring-down spectrometer, as well as a wide range of supporting analytical and sample preparation equipment.

The facility offers a graduate fellowship program in stable isotope studies and participates in collaborative research in the application of stable isotopes with scientists. The diversity of analytical capabilities provided by the SIF offers University of California, Davis faculty and students access to the latest technology in stable isotope analysis.

The SIF is a campus wide facility, housed in the Plant & Environmental Sciences Bldg. and administrated by the Department of Plant Sciences. A steering committee aids in the direction of the facility and presently consists of Drs. Chris Van Kessel, Arnold Bloom, and William Horwath.

The SIF Celebrates 20 Years of Service

December 1, 2017 marked the SIF’s 20th anniversary. To celebrate, the SIF hosted an open house with refreshments and door prizes for free analyses.

How has the SIF been a part of your research? In commemoration of our 20th anniversary, we are compiling a list of articles for our website. Please email [email protected] with your citations, including DOI if applicable.

SIF Client Publications