Microbial control of bromocarbon concentrations in coastal waters of the western Antarctic Peninsula
Microbial control of bromocarbon concentrations in coastal waters of the western Antarctic Peninsula
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DOI：
10.1016/j.marchem.2013.01.007
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发表时间：
2013-04-20
期刊：
影响因子：
3
通讯作者：
Liss, P. S.
中科院分区：
文献类型：
--
作者：
Hughes, C.;Johnson, M.;Liss, P. S.
众所周知，海洋环境是 CHBr3 和 CH2Br2 的来源，因此对流层消耗臭氧的无机溴，但迄今为止，控制其在海水中浓度的主要过程仍然知之甚少。本文报告了一系列实验室实验的结果，这些实验旨在研究最近从位于南极半岛西部沿海水域的罗瑟拉时间序列 (RaTS) 站点分离的海洋硅藻和细菌培养物中的溴碳动态。这项工作的主要焦点是中心硅藻 Thalassiosira sp 的分离。发现不同的过程可以控制该培养物中 CHBr3 和 CH2Br2 的浓度。 CHBr3 的产生仅限于生长的指数期，表明与初级代谢过程有关，并且在用抗生素处理以降低细菌活性的培养物中，CHBr3 的产生高出 5-6 倍。 (CHBr3)-C-13 添加证实 CHBr3 不会受到显着的细菌分解，因此细菌可能会抑制该化合物的产生。添加(CHBr3)-C-13后观察到的培养物中(CH2Br2)-C-13出现的比率表明硅藻培养物中CH2Br2的主要来源是从CHBr3转化而来。 CD2Br2 添加表明 CH2Br2 在两种 Thalassiosira sp. 培养物中均受到显着分解。以及表观损失率常数范围为 0.21 至 0.78 天(-1) 的细菌分离株。这些发现用于生成描述天然水中溴碳循环的经验方案，该方案根据 RaTS 站点测量的浓度数据进行验证。所提供的详细过程信息和方案为开发可与生态系统模型耦合的生物地球化学模块迈出了重要一步。然后可以利用这些数据来预测未来情景下从海到空的生物溴排放量将如何变化。 (C) 2013 Elsevier B.V. 保留所有权利。
The marine environment is known to be a source of CHBr3 and CH2Br2 and hence ozone-depleting inorganic bromine to the troposphere but, to date, the dominant processes controlling their concentrations in seawater remain poorly understood. Here results are reported from a series of laboratory experiments designed to investigate bromocarbon dynamics in cultures of marine diatoms and bacteria isolated recently from the Rothera Time-Series (RaTS) site located in coastal waters of the western Antarctic Peninsula. The main focus of this work was an isolate of the centric diatom Thalassiosira sp. Different processes were found to control the concentrations of CHBr3 and CH2Br2 in this culture. The production of CHBr3 was restricted to the exponential phase of growth suggesting a link with a primary metabolic process and was a factor of 5-6 higher in cultures treated with antibiotics to reduce bacterial activity. (CHBr3)-C-13 additions confirmed that CHBr3 was not subject to significant bacterial breakdown and hence bacteria are likely to be inhibiting the production of this compound. The rate of (CH2Br2)-C-13 appearance in the cultures observed following (CHBr3)-C-13 addition suggests that the major source of CH2Br2 in the diatom culture was transformation from CHBr3. CD2Br2 additions revealed that CH2Br2 was subject to significant breakdown in cultures of both Thalassiosira sp. and a bacterial isolate with apparent loss rate constants ranging from 0.21 to 0.78 day(-1). These findings are used to produce an empirical scheme describing bromocarbon cycling in natural waters which is validated against measured concentration data from the RaTS site. The detailed process information and schemes presented provide a major step forward towards the development of biogeochemical modules that could be coupled to ecosystem models. These could then be used to predict how sea-to-air biogenic bromine emissions will change under future scenarios. (C) 2013 Elsevier B.V. All rights reserved.