Division of Biomedical and Life Sciences, School of Health and Medicine, University of Lancaster, Lancaster, UK.
FEMS Microbiol Ecol. 2012 Nov;82(2):449-58. doi: 10.1111/j.1574-6941.2012.01423.x. Epub 2012 Jun 25.
The planktonic microbial communities of Lakes Hoare and Bonney were investigated during transition into winter. We hypothesized that the onset of darkness induces changes in the functional role of autotrophic and heterotrophic microplankton. Bacteria decreased in Lake Hoare during March-April, while in Lake Bonney bacterial abundances varied. Heterotrophic nanoflagellates (HNAN), phototrophic nanoflagellates (PNAN) and ciliates showed no marked decline with the onset of winter. PNAN outnumbered HNAN in both lakes. Grazing rates of HNAN in Lake Hoare ranged up to 30.8 bacteria per cell day(-1). The HNAN community grazed between 3.74 and 36.6 ng of bacterial carbon day(-1). Mixotrophic PNAN had grazing rates up to 15.2 bacteria per cell day(-1), and their daily community grazing exceeded bacterial production. In Lake Bonney East, PNAN grazing rates ranged up to 12.48 bacteria per cell day(-1) and in Lake Bonney West up to 8.16 bacteria per cell day(-1). As in Lake Hoare, the mixotrophic PNAN grazing rates (up to 950 ng C day(-1)) usually exceeded bacterial production. HNAN grazing rates were generally similar to those in Lake Hoare. As winter encroaches, these lakes move progressively towards heterotrophy and probably function during the winter, enabling populations to enter the short austral summer with actively growing populations.
对霍雷尔湖和邦尼湖的浮游微生物群落进行了调查,以了解它们在进入冬季时的变化情况。我们假设,黑暗的开始会改变自养和异养微型浮游生物的功能作用。在 3 月至 4 月期间,霍雷尔湖的细菌数量减少,而邦尼湖的细菌数量则有所变化。异养微型鞭毛虫(HNAN)、光养微型鞭毛虫(PNAN)和纤毛虫在冬季开始时没有明显减少。在两个湖中,PNAN 的数量都超过了 HNAN。霍雷尔湖 HNAN 的摄食率高达每细胞 30.8 个细菌/天。HNAN 群落的摄食量在 3.74 到 36.6ng 细菌碳/天之间。兼性营养的 PNAN 的摄食率高达每细胞 15.2 个细菌/天,其每日群落摄食超过了细菌的产生量。在邦尼湖东,PNAN 的摄食率高达每细胞 12.48 个细菌/天,在邦尼湖西,摄食率高达每细胞 8.16 个细菌/天。与霍雷尔湖一样,兼性营养的 PNAN 的摄食率(高达 950ng C 天)通常超过了细菌的产生量。HNAN 的摄食率通常与霍雷尔湖相似。随着冬季的临近,这些湖泊逐渐向异养转变,并且可能在冬季发挥作用,使种群在短暂的南半球夏季活跃生长。