Heterotrophic bacterial production represents an important part of microbial food web processes in marine ecosystems and plays a significant role in biogeochemical carbon cycle. As environmental factors have changed in marginal seas of the Western Pacific Ocean over the past 20 years, the response and regulation of bacterial production remain poorly understood. In this study, we quantified bacterial production rates using the 3H-leucine incorporation method and investigated the factors influencing bacterial production distributions in the East China Sea and the Yellow Sea. Our data revealed that bacterial production varied largely (1.6–24.4 mg C m−3 d−1) in the surface waters, and higher rates were observed at temperate sites in the East China Sea. Incubation experiments under different temperature or nutrient conditions demonstrated that elevated temperature or the addition of silicate, DIN and phosphate could simulate heterotrophic activity. The decadal increases of BP could be a result of microbial response to the variations in temperature, nutrient levels, and dissolved oxygen that are closely linked to food-web dynamics and biogeochemical processes. High ratios of integrated bacterial production to primary production suggested bacterial production could be supported by non-phytoplanktonic carbon sources, while the low bacterial growth efficiency indicated that a large fraction of carbon was respired in the offshore waters. These results provided insights into the regulations of BP and heterotrophic response to environmental evolution in marginal seas of the Western Pacific Ocean.

中文翻译：

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西太平洋边缘海域异养细菌生产对环境变化的调控和响应


异养细菌生产是海洋生态系统微生物食物网过程的重要组成部分，在生物地球化学碳循环中起着重要作用。由于过去 20 年西太平洋边缘海域的环境因素发生了变化，人们对细菌产生的反应和调节仍然知之甚少。在这项研究中，我们使用 3H-亮氨酸掺入方法量化了细菌生成速率，并研究了影响东海和黄海细菌生成分布的因素。我们的数据显示，表层水中的细菌产生差异很大 （1.6–24.4 mg C m-3 d-1），并且在东海的温带地区观察到更高的比率。不同温度或营养条件下的孵育实验表明，高温或添加硅酸盐、DIN 和磷酸盐可以模拟异养活性。BP 的年代际增加可能是微生物对温度、营养水平和溶解氧变化的反应的结果，这些变化与食物网动力学和生物地球化学过程密切相关。综合细菌生产与初级生产的高比率表明细菌生产可以得到非浮游植物碳源的支持，而低细菌生长效率表明大部分碳是在近海水域中呼吸的。这些结果为西太平洋边缘海 BP 的调节和异养对环境演变的响应提供了见解。