Department of Microbiology, The University of Tennessee, Knoxville, TN, USA.
FEMS Microbiol Ecol. 2014 Feb;87(2):475-85. doi: 10.1111/1574-6941.12238. Epub 2013 Nov 13.
Carbon and nutrient cycles in large temperate lakes such as Lake Erie are primarily driven by phototrophic and heterotrophic microorganisms, although our understanding of these is often constrained to late spring through summer due to logistical constraints. During periods of > 90% ice cover in February of 2008, 2009, and 2010, we collected samples from an icebreaker for an examination of bacterial production as well as microbial community structure. In comparison with summer months (August 2002 and 2010), we tested hypotheses concerning seasonal changes in microbial community diversity and production. Bacterial production estimates were c. 2 orders of magnitude higher (volume normalized) in summer relative to winter. Our observations further demonstrate that the microbial community, including single-celled phototrophs, varied in composition between August and February. Sediment traps deployed and collected over a 3 year period (2008-2011) confirmed that carbon export was ongoing and not limiting winter production. The results support the notion that active primary producers in winter months export carbon to the sediments that is not consumed until the warmer seasons. The establishment of this linkage is a critical observation in efforts to understand the extent and severity of annual summertime formations of a zone of regional hypoxia in Lake Erie.
大的温带湖泊（如伊利湖）的碳和营养循环主要受光养和异养微生物驱动，尽管由于后勤方面的限制，我们对这些微生物的理解往往仅限于春末到夏季。在 2008 年、2009 年和 2010 年 2 月超过 90%的冰覆盖期间，我们从破冰船中采集样本，以检查细菌的产生情况和微生物群落结构。与夏季（2002 年 8 月和 2010 年）相比，我们检验了关于微生物群落多样性和产生季节性变化的假设。与夏季相比，细菌产生的估计值（按体积归一化）在冬季高出约 2 个数量级。我们的观察结果进一步表明，微生物群落，包括单细胞光养生物，在 8 月和 2 月之间的组成有所不同。在 3 年（2008-2011 年）期间部署和收集的沉积物陷阱证实，碳的输出一直在进行，直到温暖季节才消耗冬季的碳。这一结果支持了这样一种观点，即在冬季活跃的初级生产者将碳输出到沉积物中，直到温暖季节才被消耗。这一联系的确立是理解伊利湖年度夏季区域性缺氧区的范围和严重程度的关键观察结果。
