Structure, fonctionnement, évolution des communautés benthiques ...

tel-00009359, version 1 - 1 Jun 2005
Chapitre 3 - Fonctionnement du réseau trophique benthique de la Grande Vasière
early spring bloom occurring ca. one month before the GASPROD cruise, and a late summer bloom
mainly located inshore during the TROPHAL cruise (Fig. 4).
Figure 4. Sea surface chlorophyll concentration in the study area in March, April and September 2002
(NASA/SeaWIFS images modified by the IFREMER OC-5 algorithm; courtesy: F. Gohin, IFREMER
Brest).
The δ 13 C values ranged from –23.15 (Stn C) to –19.70‰ (Stn F) in spring vs. –23.50 (Stn D)
to –20.90‰ (Stn G) in late summer. δ 15 N values ranged from 4.50 (Stn F) to 6.10‰ (Stn B) in spring
vs. 3.50 (Stn D) to 6.90‰ (Stn E) in September.
The POC:PON ratio ranged from 5.58 (Stn A) to 7.28 (Stn C) in spring vs. 5.55 (Stn F) to 7.39
(Stn D) in late summer. The POC:SPM ratio ranged from 0.94 (Stn G) to 1.93 (Stn F) in spring vs.
0.65 (Stn C) to 1.37 (Stn E) in September.
186