Highlights

• Cultured Chrysotila lamellosa CCMP1307 produced high proportion of C_37:4 alkenones.

• C. lamellosa U37K values reproduced the typical values for C_37:4-rich lakes.

• UK37 calibration showed a better fit with temperature than UK′37 calibration.

• The unsaturation degree of C₃₁ alkenes was also controlled by growth temperature.

Abstract

The compositions of long chain alkenes, alkenones and alkenoates in a cultured strain of the haptophyte Chrysotila lamellosa CCMP1307, isolated from a salt marsh, were investigated. The biomarker patterns were distinctive and showed a high proportion of tetraunsaturated alkenones and alkenoates, with a pronounced proportion of C₄₀ alkenones and a lack of C₃₈ methyl and C₃₉ ethyl alkenones. Linear regression of the alkenone unsaturation degree (UK37) with growth temperature (T) was obtained over the range of possible CCMP1307 growth temperature values (4–20 °C): UK37 = 0.045 × T (°C) − 1.016, (n = 13, r² 0.96), while the UK′37 values were weakly correlated with T: UK′37 = 0.0035T (°C) + 0.0511 (n = 18, r² 0.70). The UK37 calibration exhibited a low y-intercept in comparison with that of a Chinese inland lake strain reported previously. The data show significant intraspecific variation in UK37 for C. lamellosa between strains from different geographic origins. C. lamellosa CCMP1307 reproduced typical UK37 values observed in C_37:4 rich lakes, especially at lower temperature (< 15 °C). In addition, we identified C_29:2, C_31:1, C_31:2 and C_31:3 alkenes, and found that the unsaturation degree of C₃₁ alkenes (U31en), calculated with C_31:1 and C_31:2 alkenes, might also be a useful index of growth temperature for the haptophyte C. lamellosa.