Marine Biology Commons^™

Diatom Assemblages Promote Ice Formation In Large Lakes, N. A. D'Souza, Y. Kawarasaki, J. D. Gantz, R. E. Lee, B. F.N. Beall, Y. M. Shtarkman, Z. A. Koçer, S. O. Rogers, H. Wildschutte, G. S. Bullerjahn, R. M.L. Mckay

Great Lakes Institute for Environmental Research Publications

We present evidence for the directed formation of ice by planktonic communities dominated by filamentous diatoms sampled from the ice-covered Laurentian Great Lakes. We hypothesize that ice formation promotes attachment of these non-motile phytoplankton to overlying ice, thereby maintaining a favorable position for the diatoms in the photic zone. However, it is unclear whether the diatoms themselves are responsible for ice nucleation. Scanning electron microscopy revealed associations of bacterial epiphytes with the dominant diatoms of the phytoplankton assemblage, and bacteria isolated from the phytoplankton showed elevated temperatures of crystallization (T c) as high as -3 °C. Ice nucleation-active bacteria were …