Table 1.

Relative abundance and isotopic data for fatty acids from the NPSG

	Deep, >0.2 μm			Surface, 0.2–0.5 μm			Surface, >0.5 μm
Compound	Fraction	δ13C ± 1σ	∆14C* ± 1σ	Fraction	δ13C ± 1σ	∆14C* ± 1σ	Fraction	δ13C ± 1σ	∆14C* ± 1σ
14:0	0.18	−18.3 ± 0.2	114 ± 76	0.17	—†	−201 ± 261‡	0.22	−25.3 ± 0.2	—
i-15:0	—	—	—	—	—	—	0.13	−22.7 ± 0.3	48 ± 14
16:1	0.29	−21.7 ± 0.2	66 ± 47	0.13	−22.4 ± 0.2	—	0.51	−23.8 ± 0.1	—
16:0	1.00	−18.8 ± 0.2	57 ± 13	1.00	−19.0 ± 0.2	86 ± 28	1.00	−23.6 ± 0.2	51 ± 5
17:1	0.15	−25.0 ± 0.2	—	0.12	−22.8 ± 0.7	—	—	—	—
17:0	0.09	−21.5 ± 0.2	57 ± 74	0.07	—	86 ± 112	0.03	—	—
18:1	0.52	−22.7 ± 0.2	58 ± 25	0.11	−23.3 ± 0.3	−2 ± 58	0.14	−22.8 ± 1.2	52 ± 10
18:0	1.48	−18.5 ± 0.2	80 ± 11	1.78	−18.8 ± 0.2	—	0.05	−23.7 ± 1.5	93 ± 23
20:5	—	—	—	—	—	—	0.27	−25.7 ± 0.9	—
22:0	—	—	—	—	—	—	0.03	—	−201 ± 24‡

For details of isotopic measurements and background corrections, as well as AMS facility sample identifiers, see expanded Table S1, and Figs. S1 and S2.

^*Final value after all blank corrections (SI Text 1).

^†No value indicates insufficient abundance for measurement.

^‡Samples in italics were eliminated due to small size and/or unexplained contaminants.