• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Effects of phosphorus availability on cellular metals in phytoplankton: Lake Superior as a model system.
【24h】

Effects of phosphorus availability on cellular metals in phytoplankton: Lake Superior as a model system.

机译：磷的有效性对浮游植物中细胞金属的影响：苏必利尔湖作为模型系统。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The biogeochemical cycling of many metals in aquatic and marine systems is driven primarily by phytoplankton interactions with the dissolved elements. Among the numerous fundamental controls on metal stoichiometry in phytoplankton is the physiological state of the cell, which in many natural systems is strongly affected by availability of the macronutrients N and P. Low P availability is hypothesized to stimulate enhanced uptake and enriched cellular quotas for specific metals, related to up-regulated activity of specific metalloenzymes. This thesis investigates links between P availability and metal uptake in freshwater phytoplankton, using controlled laboratory incubation studies and analyses of the plankton assemblage in Lake Superior (North America), a severely P-depleted system.;Phosphorus limitation had substantial effects on the cellular metal composition of two representative freshwater algae. In Chlorella sp ( UTCC522), P limitation induced a 2-3 fold enrichment of cellular Zn, Cd and Co quotas, while in Microcystis sp (LE3 ) 3-4 fold enrichment of Co and Ni was observed. In contrast, P availability had negligible effect on cellular Fe, Mn, Cu and V in both organisms. The results were inferred to be a response to increased metal requirements of Alkaline Phosphatase (APase), which may include Zn, Cd, and Co co-factors in Chlorella, but be strictly Co-requiring in Microcystis. Elevated Ni in Microcystis suggests increased activity of Ni-requiring superoxide dismutase, resulting from oxidative stress induced by P limitation.;Measurements of seasonal and geographic ranges in the trace metal content of Lake Superior particles revealed that the ambient phytoplankton assemblage is enriched in Zn and Cu by 8-10 fold relative to predictions based on culture studies of marine and Great Lakes species. Upon P amendment, the ambient assemblage Zn and Cd quotas decreased ∼2 fold, supporting the Chlorella result, but failing to explain the magnitude of Zn enrichment in the lake. Further experiment suggested that the unusual Zn enrichment in the natural assemblage results from a combination of P limitation, extracellular adsorption, and high fractional bioavailability of dissolved Zn in the lake, while elevated Cu quotas likely result from unusually high concentrations of inorganic Cu in lake water.
机译：水和海洋系统中许多金属的生物地球化学循环主要是由浮游植物与溶解元素的相互作用所驱动。浮游植物中金属化学计量学的众多基本控制因素之一是细胞的生理状态，在许多自然系统中，大量营养素N和P的可利用性严重影响了细胞的状态。假定低P的可利用性可刺激特定物质的摄取增加和细胞配额的增加金属，与特定金属酶的上调活性有关。本文利用受控的实验室温育研究和对严重缺乏P的苏必利尔湖（北美）浮游生物组成的分析，研究了磷在淡水浮游植物中的有效性与金属吸收之间的联系。两种代表性淡水藻类的组成。在小球藻（UTCC522）中，磷限制引起细胞Zn，Cd和Co配额的2-3倍富集，而在微囊藻（LE3）中，Co和Ni的3-4倍富集。相反，磷的利用对两种生物中的细胞铁，锰，铜和钒的影响微不足道。推断该结果是对碱性磷酸酶（APase）的金属需求增加的反应，其中可能包括小球藻中的Zn，Cd和Co辅助因子，但在微囊藻中严格共同需要。微囊藻中镍的升高表明，由于P限制引起的氧化胁迫，需要Ni的超氧化物歧化酶的活性增加。通过测量苏必利尔湖中颗粒的微量金属含量的季节和地理范围，发现周围的浮游植物组合中富含Zn和相对于基于海洋和大湖物种养殖研究的预测，铜减少了8-10倍。磷修正后，周围环境中的Zn和Cd配额减少了约2倍，支持了小球藻的结果，但未能解释湖泊中Zn富集的幅度。进一步的实验表明，自然组合中锌的异常富集是由于P限制，细胞外吸附和湖中溶解的Zn的高生物利用度的综合作用所致，而Cu配额增加可能是由于湖水中无机Cu的异常高浓度所致。 。

著录项

  • 作者

    Ji, Yongcheng.;

  • 作者单位

    Rutgers The State University of New Jersey - New Brunswick.;

  • 授予单位 Rutgers The State University of New Jersey - New Brunswick.;
  • 学科 Biogeochemistry.;Biology Limnology.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 253 p.
  • 总页数 253
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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