Juhl, A. R. Scripps Inst. of Oceanography, ajuhl@ucsd.edu
, . R. ,

 
THE EFFECT OF TURBULENCE ON POPULATION GROWTH AND THE CELL CYCLE OF RED-TIDE DINOFLAGELLATES.
 
As a step towards a mechanistic understanding of how dinoflagellate growth is affected by turbulence, the growth and cell cycle progression of two red-tide species were investigated in shaken containers and Couette flow chambers. Net growth of both Lingulodinium polyedrum and Gymnodinium sanguineum was inhibited following exposure to fluid motion. Experiments on L. polyedrum revealed that sensitivity to both quantified and unquantified fluid motion depended strongly on the timing of exposure relative to the light:dark cycle. Higher sensitivity was found at dawn, which corresponds to the period of cell division. Further studies using individual cells grown in multiwell plates showed that the inhibition of net growth was driven by reduced division rates rather than by changes in mortality. Flow cytometric cell cycle analysis concurred with the other results; the lowered growth of populations which are exposed to fluid motion is explained by a reduction in the percent dividing cells and a resultant longer average G1 phase. A portion of the population may also become arrested in G2 phase. Dramatic increases in DNA/cell and cell size, as have been reported in the literature, were not observed.
 
Day: Tuesday, Feb. 2
Time: 11:30 - 11:45am
Location: Hilton of Santa Fe
 
Code: SS02TU1130H