Table 1 Results from the δ¹³C, δ¹⁵N and ¹⁴C analyses on Scutachiltonia axfordi (AM1), Yilgarniella sturtensis (AM2) copepods (cyclopoids and harpacticoids), sediment, roots, particulate organic carbon (POC), dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC).

S. axfordi

 − 24.14

 − 26.88 ± 0.05

10.71

8.81 ± 0.09

102.84 ± 0.48

19.9 ± 4.8

Modern

 − 9.6 ± 9.9

Modern

Y. sturtensis

 − 24.55

 − 27.10

9.99

8.50

100.46 ± 0.36

 − 3.7 ± 3.6

Modern

 − 0.9 ± 8.1

Modern

Cycopoida

 − 20.45 ± 0.30^a

 − 21.91 ± 0.30^a

13.90 ± 0.30

14.5 ± 0.30

100.27 ± 0.56^c

 − 5.6 ± 5.6^c

Modern^c

 − 14.7 ± 6.7^c

Modern^c

Harpacticoida

 − 20.60 ± 0.30^a

 − 23.50 ± 0.30^a

11.90 ± 0.80

15.8 ± 0.80

Roots

 − 20.57 ± 0.30^a

 − 20.90 ± 0.30^a

5.10 ± 2.0

12.1 ± 0.30

103.63 ± 0.30

27.7 ± 3.0

Modern

24.9 ± 4.7

Modern

Sediment

 − 10.33 ± 0.30^a

 − 9.65 ± 0.30^a

11.0 ± 1.20

11.4 ± 1.20

22.16 ± 3.23

 − 780.3 ± 32.1

12,100 ± 1170

 − 428.0 ± 51.7

4420 ± 725

POC

 − 21.58 ± 0.10^b

 − 26.47 ± 0.10^b

10.73 ± 0.10^b

8.35 ± 0.10^b

86.55 ± 0.76

 − 141.7 ± 7.6

1160 ± 70

 − 366.7 ± 2.8

3605 ± 35

DOC_D13

 − 29.25 ± 0.36

 − 29.35 ± 0.20

na

na

91.70 ± 0.46

 − 90.6 ± 4.6

695 ± 45

 − 83.5 ± 6.1

630 ± 60

DOC_W4

 − 31.91 ± 0.50

 − 27.15 ± 0.03

na

na

66.76 ± 0.48

 − 337.9 ± 4.8

3245 ± 60

 − 424.9 ± 5.5

4380 ± 80

DIC_D13

 − 9.45 ± 0.10^b

 − 9.39 ± 0.10^b

na

na

82.73 ± 0.30

 − 179.5 ± 3.0

1575 ± 30

 − 227.4 ± 1.9

2005 ± 20

DIC_W4

 − 8.75 ± 0.10^b

 − 8.87 ± 0.10^b

na

na

62.47 ± 0.21

 − 380.5 ± 2.1

3835 ± 30

 − 412.8 ± 1.7

4210 ± 25