Pelagic microbial activity in an arctic polynya: Testing for temperature and substrate interactions using a kinetic approach
Pelagic microbial activity in an arctic polynya: Testing for temperature and substrate interactions using a kinetic approach
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北极冰间湖中的远洋微生物活动：使用动力学方法测试温度和基质相互作用
DOI：
10.4319/lo.1999.44.8.1882
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发表时间：
1999
影响因子：
4.5
通讯作者：
J. Deming
中科院分区：
文献类型：
--
作者：
P. Yager;J. Deming
为了检验在有机质缺乏时对生活在较低温度下的高纬度海洋细菌的假设抑制作用，在夏季北极多尼雅夏季寒冷的表层水域，研究了温度和有机底物浓度对浮游微生物异养的影响。在原位(零度以下)温度和短期升温条件下，放射性标记氨基酸的利用率(掺入加呼吸)被测量为增加添加底物浓度的函数。方差分析(ANOVA)结果表明，底物浓度的增加对各站点的利用率都有显著影响，表明群落总是生活在远低于底物饱和水平的水平。大约一半的样本群落用方差分析显示出显著的温度响应；温度和底物浓度之间的相互作用很少被检测到。用于将微生物活性和底物利用与温度敏感性联系起来的动力学参数对短期变暖表现出混合反应。最大比利用率表现出更大的温度敏感性，Q10值在0.25到13之间。只有大约一半的站点比亲和力对温度有显著的响应。在最有可能受到北冰洋直接外流影响的站点观察到了嗜冷性行为(例如，在较低的孵化温度下，具有最高的比亲和力和寡营养能力)。没有发现与在零下温度下生活的细菌增强底物需求的假设完全一致。在概括或预测温度在高纬度有机物循环中的作用之前，需要更好地了解耐寒和嗜寒微生物的多样性。
To test the hypothesized inhibition of high‐latitude marine bacteria living at lower temperatures when organic matter is scarce, the effects of temperature and organic substrate concentration on pelagic microbial heterotrophy were investigated in the perennially cold surface waters of a summertime arctic polynya. Utilization (incorporation plus respiration) of radiolabeled amino acids was measured as a function of increasing added substrate concentration at in situ (subzero) temperature and under short‐term warming. Results analyzed using analysis of variance (ANOVA) showed that increased substrate concentration had a significant effect on utilization rates at all stations, suggesting that communities were always living well below saturating levels of substrate. About half of the communities sampled revealed a significant temperature response using ANOVA; interactions between temperature and substrate concentration were detected only rarely. Kinetic parameters, used to link microbial activity and substrate utilization with temperature sensitivity, exhibited mixed responses to short‐term warming. Maximum specific utilization rates showed the greater temperature sensitivity, with Q10 values ranging from 0.25 to 13. Specific affinities responded to temperature significantly at only about half of the stations in the polynya. Psychrophilic behaviors (e.g., highest specific affinities and oligotrophic capacities at lower incubation temperatures) were observed at stations most likely to be influenced by direct Arctic Ocean outflow. Complete agreement with the hypothesis of enhanced substrate requirement by bacteria living at subzero temperature was not found. An improved understanding of the diversity of cold‐tolerant and cold‐loving microorganisms is needed before generalizing or predicting the role of temperature in the cycling of organic matter at high latitudes.