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tel-00009359, version 1 - 1 Jun 2005<br />

TPM flux (g.m -2 .h -1 )<br />

50<br />

40<br />

30<br />

20<br />

10<br />

0<br />

Chapitre 3 - Fonctionnement du réseau trophique benthique de la Grande Vasière<br />

spring<br />

summer<br />

F G A B C D E<br />

Stations<br />

Figure 5. Total Particulate Matter flux (TPM, g.m -2 .h -1 ) and Particulate Organic Carbon:Total Particulate<br />

Matter ratios in particulate matter collected in the bottom-moored sediment traps during spring (April<br />

26 th to May3 rd ) and late summer (September 13 th -19 th ) sampling on the Bay of Biscay continental shelf.<br />

Stations are ranked according to an inshore-offshore gradient.<br />

The δ 13 C values in particles sedimented in the traps ranged from –22.74 (Stn D) to –20.00‰<br />

(Stn A) in spring vs. –24.62 (Stn B) to –20.35‰ (Stn G) in late summer. Stations A and G showed<br />

carbon stable isotopic ratios similar to those of the inshore station (F) overall (Table 4), while the<br />

central ‘Grande Vasière’ stations B, C and D exhibited higher δ 13 C values (-22.71 ± 0.02‰ in spring<br />

and -24.60 ± 0.04‰ in late summer). The δ 13 C value of the offshore station (E) in September was<br />

close to the values recorded on the central ‘Grande Vasière’. The δ 15 N values ranged from 2.59 (Stn<br />

C) to 4.40‰ (Stn F) in spring vs. 2.07 (Stn A) to 4.63‰ (Stn F) in late summer. The central ‘Grande<br />

Vasière’ (3.46 ± 0.60‰) exhibited a 1‰ difference with the coastal zone in spring and a 1.5‰<br />

difference in late summer (3.15 ± 0.99‰).<br />

POC flux (mg C.m -2 .h -1 )<br />

400<br />

350<br />

300<br />

250<br />

200<br />

150<br />

100<br />

50<br />

0<br />

191<br />

spring<br />

summer<br />

F G A B C D E<br />

Stations<br />

Figure 6. Particulate Organic Carbon flux (POC, mg C.m -2 .h -1 ) and Particulate Organic Carbon:Total<br />

Particulate Carbon ratios in particulate matter collected in the bottom-moored sediment traps during<br />

spring (April 26 th to May 3 rd ) and late summer (September 13 th -19 th ) sampling on the Bay of Biscay<br />

continental shelf. Stations are ranked according to an inshore-offshore gradient.<br />

0<br />

3<br />

2<br />

1<br />

0<br />

100<br />

75<br />

50<br />

25<br />

POC:TPM (%)<br />

POC:PTC (%)

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