The Laurentian Great Lakes are among the planet’s fastest-warming lakes. Recent paleolimnological studies have shown changes in the diatom community of the system, including shifts towards taxa characteristic of strongly stratified systems and ongoing cell-size diminution. Relationships between species’ cell size and establishment in—or extirpation from—the system have not been addressed. Examining patterns of establishment and extirpation provides insight into the effects of multiple stressors at the ecosystem scale. We evaluate the timing of the establishment or extirpation of diatom taxa from fossil records post-European settlement within the Great Lakes as a function of cell size. Relationships between establishment or extirpation date and cell size were not random, and were best expressed as cubic curves. Generally, large taxa became established early in the record, while establishments of smaller taxa continued apace until the late 20th century. Extirpations of taxa of all sizes accelerated in the late 20th and early 21st centuries, and large-celled taxa were disproportionately extirpated over the last two decades. We discuss the implications of these relationships on the overall cell-size characteristics of the community, and consider the influences of propagule pressure, nutrient status, species invasions, and climate change upon diatom establishment and extirpation.

中文翻译：

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大小很重要：劳伦式五大湖中硅藻的建立和灭绝时间受到细胞大小的影响

劳伦山脉五大湖是地球上增速最快的湖泊之一。最近的古脂生物学研究表明，该系统的硅藻群落发生了变化，包括向着强烈分层的系统的分类单元转移以及持续的细胞大小减少。物种的细胞大小与系统建立或灭绝之间的关系尚未得到解决。对建立和消灭的模式进行研究，可以洞察多种压力源在生态系统规模上的作用。我们评估大湖地区欧洲定居后化石记录中硅藻类群建立或灭绝的时间，作为细胞大小的函数。建立或消灭日期与细胞大小之间的关系不是随机的，最好用三次曲线表示。通常，大型分类单元在记录的早期就已建立，而较小分类单元的建立则一直持续到20世纪后期。在20世纪末和21世纪初，各种规模的分类单元的灭绝加速了，在过去的二十年中，大型细胞分类单元的灭绝比例大大提高了。我们讨论了这些关系对社区整体细胞大小特征的影响，并考虑了繁殖压力，养分状况，物种入侵和气候变化对硅藻的建立和灭绝的影响。