This is a market research notice to identify potential sources for providing simultaneous measurement of stable isotope ratios from biogenic carbonate materials. The contract would cover one base year and four one-year option periods. The applicable NAICS code is 541380 (Testing Laboratories and Services) with a $19 million size standard. Small businesses, including Section 8(a), HUBZone, SDVOSB, WOSB, and EDWOSB firms, are highly encouraged to participate. No budget amount or performance location is specified.