Effect of resource availability on bacterial community responses to increased temperature
Effect of resource availability on bacterial community responses to increased temperature
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DOI：
10.3354/ame01609
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发表时间：
2013-01-01
影响因子：
1.4
通讯作者：
Andersson, Agneta
中科院分区：
文献类型：
--
作者：
Degerman, Rickard;Dinasquet, Julie;Andersson, Agneta
预计气候变化将导致气温升高和降水增加，从而导致流入北欧沿海水域的营养物质增加。这被认为会增加整体异养性，包括增强细菌生长。然而，人们对温度、资源可用性和细菌群落组成对细菌生长反应的相对重要性知之甚少。在本研究中，我们研究了温度升高对补充不同营养浓度并接种不同季节时期微生物群落的水中细菌生长的影响。在波罗的海北部进行了七项跨越整个年度周期的实验。在每个实验中，浮游细菌暴露于 2 个温度范围（原位和原位 + 4 摄氏度）和 5 种营养浓度。一般来说，升高的温度和更高的营养水平会导致细菌生长速率增加和响应时间（滞后期）缩短。然而，在最低营养浓度下，细菌生长在所有测试温度下都很低，这意味着细菌生长对资源可用性的依赖性比对温度的依赖性更强。此外，数据表明，不同的细菌组合具有不同的温度响应，并且群落组成受到高营养添加和高温的强烈影响。这些结果支持了这样的担忧：气候变化将促进水生系统的异养，使营养水平大幅增加。在这样的环境中，细菌群落的组成会发生变化，它们的生长速度会增加，而且它们的反应时间会比现在的情况缩短。
Climate change is predicted to cause higher temperatures and increased precipitation, resulting in increased inflow of nutrients to coastal waters in northern Europe. This has been assumed to increase the overall heterotrophy, including enhanced bacterial growth. However, the relative importance of temperature, resource availability and bacterial community composition for the bacterial growth response is poorly understood. In the present study, we investigated effects of increased temperature on bacterial growth in waters supplemented with different nutrient concentrations and inoculated with microbial communities from distinct seasonal periods. Seven experiments were performed in the northern Baltic Sea spanning an entire annual cycle. In each experiment, bacterioplankton were exposed to 2 temperature regimes (in situ and in situ + 4 degrees C) and 5 nutrient concentrations. Generally, elevated temperature and higher nutrient levels caused an increase in the bacterial growth rate and a shortening of the response time (lag phase). However, at the lowest nutrient concentration, bacterial growth was low at all tested temperatures, implying a stronger dependence on resource availability than on temperature for bacterial growth. Furthermore, data indicated that different bacterial assemblages had varying temperature responses and that community composition was strongly affected by the combination of high nutrient addition and high temperature. These results support the concern that climate change will promote heterotrophy in aquatic systems, where nutrient levels will increase considerably. In such environments, the bacterial community composition will change, their growth rates will increase, and their response time will be shortened compared to the present situation.