FN Archimer Export Format PT C TI Difficulties in sampling for estimation of phytoplankton biomass in estuarine conditions : variabilities and precisions at different temporal scales in the case of the bay Marennes Oleron BT AF HERAL, Maurice GOULLETQUER, Philippe RAZET, Daniel PROU, Jean RAVAIL, Brigitte MAESTRINI, Serge AS 1:;2:;3:;4:;5:;6:; FF 1:PDG-DP2S;2:PDG-DP2S;3:PDG-DOP-LER-LERPC;4:PDG-DPCP;5:;6:; SI SIEGE NANTES LA TREMBLADE SE PDG-DP2S PDG-DOP-LER-LERPC PDG-DPCP UR https://archimer.ifremer.fr/doc/1988/acte-2877.pdf LA English DT Proceedings paper DE ;Marennes Oleron;Phytoplanktonic biomasses;Estimation AB Different sampling strategies have been tested for estimation of phytoplanktonic biomasses in a bay submitted to estuarine conditions and high velocity of currents. Daily variations showed that for a precision of 5% of the daily mean, it is necessary to sample with a 1 hour and a half time scale. Systematic sampling appears to be more preceise than the random sampling. A sampling during 35 days at low tide and at high tide, during the phytoplanktonic bloom, showed the large variability between the days. A precision of 30% of the mean biomass of the month is obtained with a 8 days time scale. Comparison between tidal cycle sampling (10% of precision) with a punctual sample in the middle of the day did not show large differences. As the main variability is between the days and not during on day, the autors suggest to sample 2 daus by week during the bloom. Different sampling strategies have been tested for the estimation of phytoplanktonic biomasses in a microtidal bay submitted to estuarine conditions and high velocity of currents. The study has been realised in two areas in the center of the bay (station 1, fig.1) wich is well representative of the evolution of the whole bay (Héral et al., 1983) and in the external estuary of the river Charente (station 2, fig. 1) PY 1988 CT Actes workshop, La Rochelle, France, 16-12 april 1988, Editors Maestrini & Rassoulzadegan, Masson, Paris ID 2877 ER EF