Institute of Environmental Science and Technology (ICTA), Autonomous University of Barcelona (UAB), Bellaterra, Barcelona, Spain.
The Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, Devon, PL1 2PB, United Kingdom.
PLoS One. 2018 Mar 20;13(3):e0194386. doi: 10.1371/journal.pone.0194386. eCollection 2018.
The sinking properties of three strains of Emiliania huxleyi in response to temperature changes were examined. We used a recently proposed approach to calculate sinking velocities from coccosphere architecture, which has the advantage to be applicable not only to culture samples, but also to field samples including fossil material. Our data show that temperature in the sub-optimal range impacts sinking velocity of E. huxleyi. This response is widespread among strains isolated in different locations and moreover comparatively predictable, as indicated by the similar slopes of the linear regressions. Sinking velocity was positively correlated to temperature as well as individual cell PIC/POC over the sub-optimum to optimum temperature range in all strains. In the context of climate change our data point to an important influence of global warming on sinking velocities. It has recently been shown that seawater acidification has no effect on sinking velocity of a Mediterranean E. huxleyi strain, while nutrient limitation seems to have a small negative effect on sinking velocity. Given that warming, acidification, and lowered nutrient availability will occur simultaneously under climate change scenarios, the question is what the net effect of different influential factors will be. For example, will the effects of warming and nutrient limitation cancel? This question cannot be answered conclusively but analyses of field samples in addition to laboratory culture studies will improve predictions because in field samples multi-factor influences and even evolutionary changes are not excluded. As mentioned above, the approach of determining sinking rate followed here is applicable to field samples. Future studies could use it to analyse not only seasonal and geographic patterns but also changes in sinking velocity over geological time scales.
我们研究了三株赫氏海豆芽（Emiliania huxleyi）对温度变化的下沉特性。我们采用了一种新方法，根据球形体结构计算下沉速度，这种方法不仅适用于培养样本，也适用于包括化石材料在内的野外样本。我们的数据表明，亚适温范围的温度会影响赫氏海豆芽的下沉速度。这种反应在不同地点分离的菌株中很普遍，而且具有一定的可预测性，因为线性回归的斜率相似。在所有菌株中，亚适温至最适温范围内，下沉速度与温度以及单个细胞的 PIC/POC 呈正相关。在气候变化的背景下，我们的数据表明，全球变暖对下沉速度有重要影响。最近的研究表明，海水酸化对地中海赫氏海豆芽菌株的下沉速度没有影响，而营养限制似乎对下沉速度有轻微的负面影响。在气候变化情景下，升温、酸化和营养物质减少将同时发生，因此，问题是不同影响因素的净效应是什么。例如，升温和营养限制的影响会相互抵消吗？这个问题不能得出明确的结论，但除了实验室培养研究外，对野外样本的分析将改善预测，因为在野外样本中，多因素影响甚至进化变化都不能被排除。如前所述，这里采用的确定下沉率的方法适用于野外样本。未来的研究可以利用它来分析不仅是季节性和地理模式，还有地质时间尺度上的下沉速度变化。
