Department of Ecology, University of Kaiserslautern, Kaiserslautern, Germany.
PLoS One. 2007 Aug 15;2(8):e728. doi: 10.1371/journal.pone.0000728.
The impact of climate on biodiversity is indisputable. Climate changes over geological time must have significantly influenced the evolution of biodiversity, ultimately leading to its present pattern. Here we consider the paleoclimate data record, inferring that present-day hot and cold environments should contain, respectively, the largest and the smallest diversity of ancestral lineages of microbial eukaryotes.
METHODOLOGY/PRINCIPAL FINDINGS: We investigate this hypothesis by analyzing an original dataset of 18S rRNA gene sequences from Western Greenland in the Arctic, and data from the existing literature on 18S rRNA gene diversity in hydrothermal vent, temperate sediments, and anoxic water column communities. Unexpectedly, the community from the cold environment emerged as one of the richest observed to date in protistan species, and most diverse in ancestral lineages.
CONCLUSIONS/SIGNIFICANCE: This pattern is consistent with natural selection sweeps on aerobic non-psychrophilic microbial eukaryotes repeatedly caused by low temperatures and global anoxia of snowball Earth conditions. It implies that cold refuges persisted through the periods of greenhouse conditions, which agrees with some, although not all, current views on the extent of the past global cooling and warming events. We therefore identify cold environments as promising targets for microbial discovery.
气候对生物多样性的影响是不可否认的。地质时期的气候变化肯定对生物多样性的进化产生了重大影响，最终导致了其目前的模式。在这里，我们考虑古气候数据记录，推断现今的热环境和冷环境应该分别包含微生物真核生物祖先谱系的最大和最小多样性。
方法/主要发现：我们通过分析来自北极格陵兰西部的 18S rRNA 基因序列的原始数据集，并结合来自热液喷口、温带沉积物和缺氧水柱群落的 18S rRNA 基因多样性的现有文献数据，来验证这一假说。出乎意料的是，冷环境中的群落是迄今为止观察到的最丰富的原生动物物种之一，而且在祖先谱系中也是最多样化的。
结论/意义：这种模式与雪球地球条件下低温和全球缺氧反复对需氧非嗜冷微生物真核生物进行自然选择扫荡的理论相一致。这意味着冷避难所一直存在于温室条件时期，这与目前关于过去全球变冷和变暖事件的范围的一些观点一致，但不是所有观点都一致。因此，我们将冷环境确定为微生物发现的有希望的目标。
