Variable but persistent coexistence of Prochlorococcus ecotypes along temperature gradients in the ocean's surface mixed layer
Variable but persistent coexistence of Prochlorococcus ecotypes along temperature gradients in the ocean's surface mixed layer
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DOI：
10.1111/1758-2229.12378
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发表时间：
2016-04-01
影响因子：
3.3
通讯作者：
Zinser, Erik R.
中科院分区：
文献类型：
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作者：
Chandler, Jeremy W.;Lin, Yajuan;Zinser, Erik R.
贫营养海洋表层混合层中的浮游植物群落绝大多数是由原绿球藻eMIT 9312或eMED 4两种生态型之一占主导地位。在这项研究中，我们调查了大西洋和太平洋的大纬度断面，以确定这些生态型离散分区的表面混合层生态位，或者如果人口存在作为一个连续体沿着关键的环境梯度，特别是温度。优势的转变发生在大约19-21摄氏度，eMED 4生态型占主导地位的较冷的地区，和eMIT 9312生态型占主导地位的温暖地区。然而，在这些区域优势区内，少数生态类型并没有竞争到灭绝。相反，生态型比率与温度之间的稳健对数线性关系表征了这种稳定的共存：温度每升高2.5摄氏度，eMIT 9312：eMED 4比率增加一个数量级。在定量聚合酶链反应和焦磷酸测序测定中均观察到这种关系。水柱分层也有助于生态型比沿着流域尺度的样带，但在较小程度上。最后，确定了eMED 4和eMIT 9312丰度的比率与温度不相关的情况。这种情况可能是由于水温的变化超过了群落结构的变化。
The vast majority of the phytoplankton communities in surface mixed layer of the oligotrophic ocean are numerically dominated by one of two ecotypes of Prochlorococcus, eMIT9312 or eMED4. In this study, we surveyed large latitudinal transects in the Atlantic and Pacific Ocean to determine if these ecotypes discretely partition the surface mixed layer niche, or if populations exist as a continuum along key environmental gradients, particularly temperature. Transitions of dominance occurred at approximately 19-21 degrees C, with the eMED4 ecotype dominating the colder, and eMIT9312 ecotype dominating the warmer regions. Within these zones of regional dominance, however, the minority ecotype was not competed to extinction. Rather, a robust log-linear relationship between ecotype ratio and temperature characterized this stabilized coexistence: for every 2.5 degrees C increase in temperature, the eMIT9312:eMED4 ratio increased by an order of magnitude. This relationship was observed in both quantitative polymerase chain reaction and in pyrosequencing assays. Water column stratification also contributed to the ecotype ratio along the basin-scale transects, but to a lesser extent. Finally, instances where the ratio of the eMED4 and eMIT9312 abundances did not correlate well with temperature were identified. Such occurrences are likely due to changes in water temperatures outpacing changes in community structure.