FN Archimer Export Format PT J TI Phased oscillations in cell numbers and nitrate in batch cultures of Alexandrium tamarense (Dinophyceae) BT AF COLLOS, Yves HADJADJI, Imene PLISSON, Benoit CECCHI, Philippe LAABIR, Mohamed BECHEMIN, Christian MASSERET, Estelle AS 1:1;2:1;3:1;4:1;5:1;6:2;7:1; FF 1:;2:;3:;4:;5:;6:PDG-ODE-LER-LERPC;7:; C1 Univ Montpellier 2, IRD, UMR CNRS 5119, CC093, F-34095 Montpellier 5, France. IFREMER, Lab Environm Ressources Pertuis Charentais, F-17137 Lhoumeau, France. C2 UNIV MONTPELLIER, FRANCE IFREMER, FRANCE SI LA ROCHELLE SE PDG-ODE-LER-LERPC IN WOS Ifremer jusqu'en 2018 copubli-france copubli-univ-france IF 2.071 TC 5 UR https://archimer.ifremer.fr/doc/00049/16046/13585.pdf LA English DT Article DE ;Alexandrium tamarense;archaea;bacteria;decay;growth;nitrate;nitrification;oscillations AB Alexandrium tamarense (M. Lebour) Balech strains isolated in spring 2007 from a single bloom in Thau lagoon have been grown in nonaxenic artificial media. For three strains showing large oscillations in biomass (crashes followed by recoveries) on a scale of several days, a significant relationship was observed between changes in cell densities (as in vivo fluorescence) and changes in nitrate concentrations. Increases in cell densities were accompanied by decreases in nitrate, while decreases in cell densities corresponded to increases in nitrate, presumably due to nitrification. Net increases in nitrate could reach up to 15 mu mol N . L(-1) . d(-1) indicating a very active nitrifying archaeal/bacterial population. However, following population crashes, algal cells can recover and attain biomass levels similar to those reached during the first growth phase. This finding indicates that those archaea/bacteria do not compete for nutrients or do not hamper algal growth under those conditions. In contrast to diatoms, dinoflagellates such as A. tamarense do not excrete/exude dissolved organic matter, thus preventing excessive bacterial growth. This mechanism could help explain the recovery of this species in the presence of bacteria. PY 2011 PD OCT SO Journal Of Phycology SN 0022-3646 PU Wiley-blackwell VL 47 IS 5 UT 000296084800011 BP 1057 EP 1062 DI 10.1111/j.1529-8817.2011.01031.x ID 16046 ER EF