Evaluation of functionality as a seed population of resting stage cells of centric diatoms in surface sediments of Ago Bay, central part of Japan
2009
Ueno, R.(Mie Univ., Tsu (Japan)) | Ishikawa, A.
The abundance and species composition of viable resting stage cells and vegetative cells of centric diatoms were investigated in Ago Bay in May and July, 2006, and in March 2007 to evaluate the functionality of the resting stage cells as a seed population. Viable resting stage cells in the surface sediments were enumerated by the extinction dilution method (most probable number method). High densities of resting stage cells (6.1 x 10E3-2.4 x 10E5 resting stage cells/cubic m) were detected throughout the study period. In the assemblage of resting stage cells, 8 genera 25 species in total were identified. Among the 25 species, 24 species (i.e. 96% of the total) were observed in the assemblage of vegetative cells, suggesting that the resting stage cells in the surface sediments function well as a seed population for the vegetative cells. However, the abundance and composition of the dominant groups in the sediments did not always correspond to those in the water column. This does not however point to a lack of importance of resting stage cells as seeds, since bloom dynamics after recruitment of newly germinated/rejuvenated cells into the water column are largely dependent on vegetative growth, which is controlled by many environmental factors. Furthermore, this study suggested that species diversity in the vegetative assemblage of centric diatoms in Ago Bay is substantially supported by the seed population in the surface sediments.
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