King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, Thuwal, Saudi Arabia.
Centro Oceanográfico de Gijón/Xixón, Instituto Español de Oceanografía (IEO), Gijón/Xixón, Spain.
Environ Microbiol. 2018 Oct;20(10):3798-3810. doi: 10.1111/1462-2920.14393. Epub 2018 Oct 10.
Recent work suggests that temperature effects on marine heterotrophic bacteria are strongly seasonal, but few attempts have been made to concurrently assess them across trophic levels. Here, we estimated the temperature sensitivities (using activation energies, E) of autotrophic and heterotrophic microbial plankton net growth rates over an annual cycle in NE Atlantic coastal waters. Phytoplankton grew in winter and late autumn (0.41 ± 0.16 SE d ) and decayed in the remaining months (-0.42 ± 0.10 d ). Heterotrophic microbes shared a similar seasonality, with positive net growth for bacteria (0.14-1.48 d ), while nanoflagellates had higher values (> 0.4 d ) in winter and spring relative to the rest of the year (-0.46 to 0.29 d ). Net growth rates activation energies showed similar dynamics in the three groups (-1.07 to 1.51 eV), characterized by maxima in winter, minima in summer and resumed increases in autumn. Microbial plankton E values were significantly correlated with nitrate concentrations as a proxy for nutrient availability. Nutrient-sufficiency (i.e., > 1 μmol l nitrate) resulted in significantly higher activation energies of phytoplankton and heterotrophic nanoflagellates relative to nutrient-limited conditions. We suggest that only within spatio-temporal windows of both moderate bottom-up and top-down controls will temperature have a major enhancing effect on microbial growth.
最近的研究表明，海洋异养细菌对温度的影响具有很强的季节性，但很少有人试图同时评估它们在不同营养水平上的影响。在这里，我们在东北大西洋沿海水域的一个年周期内，估计了自养和异养微生物浮游生物净生长率的温度敏感性（使用激活能，E）。浮游植物在冬季和晚秋生长（0.41±0.16 SE d），而在其余月份则衰减（-0.42±0.10 d）。异养微生物具有相似的季节性，细菌的净生长为正（0.14-1.48 d），而纳米鞭毛虫在冬季和春季的净生长值高于一年中的其他时间（-0.46 至 0.29 d）。三组的净生长率激活能表现出相似的动态变化（-1.07 至 1.51 eV），以冬季最大值、夏季最小值和秋季再次增加为特征。微生物浮游生物的 E 值与硝酸盐浓度呈显著正相关，硝酸盐浓度是营养物质可利用性的代表。在营养充足（即硝酸盐>1 μmol l）的条件下，浮游植物和异养纳米鞭毛虫的激活能明显高于营养限制条件。我们认为，只有在适度的上下控制的时空窗口内，温度才会对微生物生长产生主要的促进作用。
