4月8日，国际著名杂志《自然—地球科学》Nature Geoscience的一项报告指出，作为世界上唯一一种最重要的海洋钙化有机体，海洋球石藻可通过自身进化以应对海洋酸化。
海水酸化，由海洋吸收大气中二氧化碳所引起，可严重损害海洋钙化有机体。到目前为止，有关海水酸化对海洋生物影响的研究都聚焦在个体生命周期内的生理应答上，却很大程度上忽视了进化的潜在可能。
在一系列实验中，Thorsten Reusch和同事将海洋球石藻暴露于高浓度的二氧化碳中，在海洋球石藻经过约500次无性繁殖后，他们对其在海水酸化条件下的状态进行了评估。结果发现，虽然在海水酸化条件下，所有的藻类生存状态都变差，但与对照条件的藻类相比，处于高浓度二氧化碳条件的那一些藻类却表现出更高的生长速率以及钙化物质的部分复原。
研究人员表示，这种同步进化能有助于在全球气候变化的情况下维持海洋微生物的功能。（生物谷Bioon.com）
doi:10.1038/ngeo1441
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Adaptive evolution of a key phytoplankton species to ocean acidification
Kai T. Lohbeck, Ulf Riebesell & Thorsten B. H. Reusch
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.
