Structure, fonctionnement, évolution des communautés benthiques ...

tel-00009359, version 1 - 1 Jun 2005
Mean gross particle fluxes
Chapitre 3 - Fonctionnement du réseau trophique benthique de la Grande Vasière
Mean values of the 12-h sediment trap deployments are summarised in Table 4. These results
correspond to the gross sedimentation (net sedimentation + sedimentation of re-suspended matter).
Parameter ranges
As for bottom-water suspended particulate matter, the null hypothesis of mean global
homogeneity must be rejected in all cases (ANOVA, p 90%) in the station under the river plumes influence (F), intermediate
values in G (66 to 80%) and lowest values in the central ‘Grande Vasière’ stations (26 to 43-68%).
The PON fluxes were in the ranges 5-18 mg N.m -2 .h -1 in spring, vs. 1-18 mg N.m -2 .h -1 in late
summer. Mean PON fluxes on the central ‘Grande Vasière’ stations were 7.77 ± 2.24 mg N.m -2 .h -1 in
spring, vs. 2.18 ± 0.76 mg N.m -2 .h -1 in late summer. As for POC fluxes, higher values were found in
the coastal zone (Stn F: 17.77 and 4.75 mg N.m -2 .h -1 in spring and late summer, respectively), but the
seasonal trend was similar that is a 3.5-fold decrease in PON flux between spring and late summer.
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