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The hydrocarbons in cultures of marine haptophytes Emiliania huxleyi NIES837 and Gephyrocapsa oceanica NIES1315 were analyzed, and nonacosadienes and hentriacontadienes were detected as the major compounds in both strains. C29 and C31 monoenes and di-, tri- and tetra-unsaturated C33 alkenes were also detected as minor compounds but not C37 and C38 alkenes. The positions of the double bonds in the C29 and C31 alkenes were determined by mass spectrometry of their dimethyl disulfide (DMDS) adducts. Among the four C29 alkenes identified, the most abundant isomer was 2,20-nonacosadiene, and the other three compounds were 1,20-nonacosadiene, 3,20-nonacosadiene and 9-nonacosene, respectively. Hitherto, 2,20-nonacosadiene and 3,20-nonacosadiene were unknown to be natural products. The double bond at the n-9 (ω9) position in these C29 alkenes is hypothesized to be derived from precursors of unsaturated fatty acids possessing an n-9 double bond, such as (9Z)-9-octadecenoic acid. Nonacosadienes have the potential for being used as distinct haptophyte biomarkers.

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 C 40 alkenones and a lack of C 38 methyl and C 39 ethyl alkenones. Linear regression of the alkenone unsaturation degree ( U 37 K ) with growth temperature ( T ) was obtained over the range of possible CCMP1307 growth temperature values (4–20 °C): U 37 K = 0.045 × T (°C) − 1.016, ( n = 13, r 2 0.96), while the U 37 K ′ values were weakly correlated with T : U 37 K ′ = 0.0035 T (°C) + 0.0511 ( n = 18, r 2 0.70). The U 37 K 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 U 37 K for C. lamellosa between strains from different geographic origins. C. lamellosa CCMP1307 reproduced typical U 37 K values observed in C 37:4 rich lakes, especially at lower temperature ( 29:2 , C 31:1 , C 31:2 and C 31:3 alkenes, and found that the unsaturation degree of C 31 alkenes ( U 31 en ), calculated with C 31:1 and C 31:2 alkenes, might also be a useful index of growth temperature for the haptophyte C. lamellosa .