首页> 外文期刊>Marine Chemistry >Concentration dependent nitrogen isotope fractionation during ammonium uptake by phytoplankton under an algal bloom condition in the Danshuei estuary, northern Taiwan
【24h】

Concentration dependent nitrogen isotope fractionation during ammonium uptake by phytoplankton under an algal bloom condition in the Danshuei estuary, northern Taiwan

机译:台湾北部淡水河口藻华条件下浮游植物吸收铵盐时氮浓度的浓度依赖性分馏

获取原文
获取原文并翻译 | 示例
           

摘要

In July 2009 an intense algal bloom with maximum Chl-a concentration reaching 166 ng L~(-1) occurred in the highly eutrophic Danshuei River estuary, which receives waste discharges from the densely populated Taipei metropolitan area in northern Taiwan. The estuary is often burdened with very high concentration of ammonium (up to -550 μM), which dominates the dissolved inorganic nitrogen species in the estuary. The observed δ~(15)N values of particulate nitrogen ranged from -8.6‰ to 0.2‰, and the δ~(15)N values of coexisting ammonium ranged from 4.6 to 11.9‰. Notably the offset between δ~(15)Npn and δ~(15)N_(NH_4) (△δ~(15)N) showed significant correlation with ammonium concentration. The e-values were calculated to be between - 4.7 and -16.4‰. The range overlaps with that of previous estimates (- 6.5 to -18.1‰) based on field observations. We plotted all field observed e-values vs. corresponding ammonium concentrations and found a trend similar to that previously observed for marine bacterium. Vibrio harveyi, in laboratory cultures. Thus, we constructed a concentration dependent curve of the e-value for ammonium uptake by phytoplankton in natural waters. The curve shows the maximum magnitude of e-value (- 20‰) at ammonium concentration around 100 μM with decreasing isotope effect on both sides; at lower concentrations, the e-value diminishes to zero; at higher concentrations, it slopes gradually towards an asymptotic value around -2‰. More than half of the e-values derived from laboratory cultures of diatoms also fall on this curve. However, a few culture-based e-values fall on another curve with similar pattern but considerably larger maximum magnitude. The maximum isotope effect is probably attributed to the cumulative isotope effects from ammonium deprotonation and the subsequent membrane diffusion of ammonia. This study provides the first field observed evidence of concentration dependent nitrogen isotope fractionation during ammonium uptake by phytoplankton and reconciles partially the disparity between estimates from field observations and from laboratory cultures.
机译:2009年7月,在高度富营养化的淡水河口发生了强烈的藻华,最大Chl-a浓度达到166 ng L〜(-1),该河口接收来自台湾北部人口稠密的台北都会区的废物。河口经常担负着非常高浓度的氨(高达-550μM),氨占河口中溶解的无机氮的主要成分。观测到的颗粒氮的δ〜(15)N值为-8.6‰至0.2‰,共存铵的δ〜(15)N值为4.6至11.9‰。值得注意的是δ〜(15)Npn和δ〜(15)N_(NH_4)(△δ〜(15)N)之间的偏移与铵浓度呈显着相关。 e值经计算介于-4.7和-16.4‰之间。根据实地观测,该范围与先前估计的范围(-6.5至-18.1‰)重叠。我们绘制了所有实地观察到的e值与相应的铵浓度的关系图,发现了与以前观察到的海洋细菌相似的趋势。哈维弧菌,实验室培养。因此,我们构建了自然水中浮游植物对氨吸收的e值的浓度依赖性曲线。曲线显示了铵浓度为100μM时e值的最大幅度(-20‰),且两侧的同位素效应均降低;在较低浓度下,e值减小为零;在较高浓度下,它逐渐向-2‰附近的渐近值倾斜。来自硅藻实验室培养的e值的一半以上也落在该曲线上。但是,一些基于文化的e值落在另一条曲线上,该曲线具有相似的模式,但最大幅度较大。最大的同位素效应可能归因于铵去质子化和随后氨膜扩散所产生的累积同位素效应。这项研究提供了第一个现场观察到的证据,表明浮游植物吸收铵时浓度依赖性氮同位素分馏,并部分调和了现场观察和实验室培养的估算之间的差异。

著录项

  • 来源
    《Marine Chemistry》 |2013年第20期|242-252|共11页
  • 作者单位

    Institute of Hydrological and Oceanic Sciences, National Central University, Jungli, Taoyuan 32001, Taiwan, ROC;

    Research Center for Environmental Changes, Academic Sinica, Nankang, Taipei 115, Taiwan, ROC;

    Institute of Marine Environmental Chemistry and Ecology and Center ofExcellencefor Marine Bioenvironment and Biotechnology. National Taiwan Ocean University, Keelung 20224, Taiwan, ROC;

    Institute of Marine Environmental Chemistry and Ecology, NTOU, Keelung and Taiwan Ocean Research Institute, Kaohsiung, Taiwan, ROC;

    Institute of Marine Biology, National Taiwan Ocean University, Keelung 20224, Taiwan, ROC;

    Institute of Hydrobgical and Oceanic Sciences, National Central University, Jungli 32001, Taiwan, ROC;

    Institute of Hydrobgical and Oceanic Sciences, National Central University, Jungli 32001, Taiwan, ROC;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Particulate nitrogen; River estuary; Diatoms; Isotope effect; Ammonium assimilation; Variable isotope fractionation;

    机译:颗粒氮;河口硅藻;同位素效应铵同化;可变同位素分馏;

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号