Resting stages and ecology of the planktonic diatom Aulacoseira skvortzowii in Lake Baikal
Resting stages and ecology of the planktonic diatom Aulacoseira skvortzowii in Lake Baikal
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DOI：
10.4319/lo.2008.53.3.1125
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发表时间：
2008-05-01
影响因子：
4.5
通讯作者：
Gnatovsky, Ruslan Yu.
中科院分区：
文献类型：
--
作者：
Jewson, David H.;Granin, Nick G.;Gnatovsky, Ruslan Yu.
贝加尔湖浮游硅藻的种群在低于4℃时发育，在高于6.5℃时死亡率迅速上升，休眠孢子在与夏季分层相关的温度升高之前产生。磷素浓度降至15 ~ 20 μ g L-1 P-PO4以下为产孢的主要线索。如果磷酸盐在分层开始后下降，孢子形成就很差。在培养中，当磷酸盐限制时，所有细胞都产生孢子，但当硝酸盐限制时，只有15%的细胞产生孢子。此外，孢子的形成与直径有关，大多数狭窄的细胞转向大小再生。这影响了种群动态，南部和中部盆地的生物量较高，而北部盆地的生物量很少，因为磷酸盐并不总是低于产孢和大小再生所需的诱导阈值，导致招募不良。在培养中，当孢子放置在新的培养基中，即使在黑暗中，储存的储备也足以完成两到三次分裂时，萌发就发生了。这有助于种群在夏季休眠的沿海沉积物受到波浪作用时重新恢复。
Populations of the planktonic diatom Aulacoseira skvortzowii in Lake Baikal developed below 4 degrees C, with mortality increasing rapidly at temperatures above 6.5 degrees C. Resting spores were produced before the temperature rise associated with summer stratification. The main cue for sporulation was a decline in phosphate concentration below 15-20 mu g L-1 P-PO4. If phosphate declined after the onset of stratification, sporulation was poor. In culture, all cells sporulated when phosphate limited but only 15% did so when nitrate limited. Also, spore formation was diameter dependent, with most narrow cells switching to size regeneration. This affected population dynamics, with high biomasses developing in the south and middle basins but only rarely in the north basin, because phosphate did not always fall below the induction threshold necessary for sporulation and size regeneration, leading to poor recruitment. In culture, germination occurred when spores were placed in new media, with stored reserves sufficient to complete two to three divisions, even in the dark. This helped populations re-establish when resuspended by wave action from coastal sediments where they lay dormant during summer.