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A growing body of work has demonstrated that the δ²H values of alkenones reflect the δ²H values (δ²H_H2O) and / or salinity of the fluid in which they are produced. If so, δ²H_alkenone values would act as a surface seawater isotope / salinity proxy, similar to foraminiferal δ¹⁸O values, but advantaged in locations with poor carbonate preservation and / or high organic content. Nevertheless, laboratory culture, sediment trap, and water column studies have failed to consistently characterize the effects of temperature, alkenone-producing species, and salinity itself on the δ²H_alkenone-salinity and -seawater isotope relationships, and a robust sedimentary alkenone-based calibration remains elusive.

Most δ²H_alkenone datasets report δ²H_C37, i.e., combined δ²H_C37:3 and δ²H_C37:2 values, and differ in how they address inter-alkenone fractionation (i.e., α_C37:3-C37:2). To constrain controls on alkenone hydrogen …