| Microphytobenthic biomass was estimated in the Bay of Brest (1994) and the western English Channel (Trezen Vraz, 1993) using spectrophotometry. Best results (42 % difference) were obtained with an instantaneous extraction procedure at room temperature, compared with the cold extraction procedure. Chlorophyll biomass in sediment was higher in the western English Channel (65-215 mg Chl a m(-2)) than in the Bay of Brest (10-113 mg Chl a m(-2)), in contrast to total pigment biomass (Chl a + pheo a : 88-254 mg m(-2) at Trezen Vraz vs. 131-934 mg m(-2) in the Bay of Brest). This study emphasized decreasing pigment biomass from the estuary to the open sea. Low benthic pigment biomass in the Bay, compared to eutrophic ecosystems, agrees with previous studies on... |
