Table 2 Organic geochemical composition of the studied hydrothermal samples on Iceland.

From: Fingerprinting molecular and isotopic biosignatures on different hydrothermal scenarios of Iceland, an acidic and sulfur-rich Mars analog

Sample

TOC (% dw)a

TN (% dw)b

δ13C (‰)c

δ15Nv(‰)d

Total lipids (µg·g−1 dw)e

n-fatty acids/n-alkanesf

br-C17/n-C17g

MAT-54

1.03

0.18

− 18.2

0.59

27

7

0.069

MAT-70

3.59

0.45

− 17.9

− 0.87

105

4

0.28

MAT-78

5.12

0.88

− 20.8

− 5.4

17

4

0.11

MP-74

0.41

0.09

− 16.1

− 2.7

3.3

11

0.098

MP-87

0.14

nd

− 21.2

nd

0.62

1.6

2.4

AF-25

0.11

nd

− 16.7

nd

3.9

1.3

0.11

AF-90

0.16

nd

− 8.1

nd

2.2

1.2

1.4

IF-20

0.02

nd

− 21.1

nd

1.2

0.80

0.60

IF-49

0.02

nd

− 20.2

nd

0.88

1.1

0.10

IF-66

0.03

nd

− 10.0

nd

1.5

1.2

0.44

IF-74

0.01

nd

− 20.1

nd

1.3

0.99

0.14

  1. aTotal organic carbon (TOC).
  2. bTotal nitrogen (TN).
  3. cBulk stable carbon isotopic composition of TOC.
  4. dBulk stable nitrogen isotopic composition of TN.
  5. eTotal sum of lipids including compounds from the apolar (n-alkanes, isomeric n-alkenes, isoprenoids), acid (n-fatty acids, i/a-fatty acids, mono- and polyunsaturated fatty acids, and cyclopropyl fatty acids), and polar (n-alkanols, phytol, and sterols) fractions (see Fig. S1, S3, S4 for details on the lipids distributions).
  6. fRatio of saturated straight-chain (normal) fatty acids (n-fatty acids) over n-alkanes. Estimate of freshness or extent of biological activity.
  7. gSum of branched heptadecanes over n-heptadecane. Estimate of the relative abundance of heterotrophs57.
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