Adaptive evolution of a key phytoplankton species to ocean acidification
Adaptive evolution of a key phytoplankton species to ocean acidification
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DOI：
10.1038/ngeo1441
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发表时间：
2012-05-01
影响因子：
18.3
通讯作者：
Reusch, Thorsten B. H.
中科院分区：
文献类型：
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作者：
Lohbeck, Kai T.;Riebesell, Ulf;Reusch, Thorsten B. H.
海洋酸化，海水pH值的下降与燃烧化石燃料的二氧化碳持续富集有关，可能会严重损害海洋钙化生物体。我们目前对海洋生物对海洋酸化的敏感性的理解主要基于短期实验，其中生物体暴露于二氧化碳浓度升高。但是，尤其是生成时间短的浮游植物物种可能能够通过适应性进化来应对环境改变。在这里，我们研究了世界上最重要的钙化生物，Coccolithore emiliania huxleyi在两个500代选择实验中响应海洋酸化而演变的能力。具体而言，我们暴露了由单个或多个克隆建立的Huxleyi种群，以增加二氧化碳浓度。大约500世代后，我们评估了它们的健康状况。与保持环境二氧化碳部分压力的种群相比，在海洋酸化条件下进行测试时，在单一和多酮实验中，在二压较高的人群中选择的人群都显示出更高的生长速率。钙化部分恢复了：在所有培养物中，在CO2条件下增加的速率均较低，但与非适应性培养物相比，适应性的钙化率均高出50％。我们建议，面对全球变化，当代的进化可以帮助维持在海洋食品网基底部的微生物过程的功能。
Ocean acidification, the drop in seawater pH associated with the ongoing enrichment of marine waters with carbon dioxide from fossil fuel burning, may seriously impair marine calcifying organisms. Our present understanding of the sensitivity of marine life to ocean acidification is based primarily on short-term experiments, in which organisms are exposed to increased concentrations of CO2. However, phytoplankton species with short generation times, in particular, may be able to respond to environmental alterations through adaptive evolution. Here, we examine the ability of the world's single most important calcifying organism, the coccolithophore Emiliania huxleyi, to evolve in response to ocean acidification in two 500-generation selection experiments. Specifically, we exposed E. huxleyi populations founded by single or multiple clones to increased concentrations of CO2. Around 500 asexual generations later we assessed their fitness. Compared with populations kept at ambient CO2 partial pressure, those selected at increased partial pressure exhibited higher growth rates, in both the single-and multiclone experiment, when tested under ocean acidification conditions. Calcification was partly restored: rates were lower under increased CO2 conditions in all cultures, but were up to 50% higher in adapted compared with non-adapted cultures. We suggest that contemporary evolution could help to maintain the functionality of microbial processes at the base of marine food webs in the face of global change.