• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Ecology and water quality dynamics of a shallow hypereutrophic lake dominated by cyanobacteria (Aphanizomenon flos-aquae).
【24h】

Ecology and water quality dynamics of a shallow hypereutrophic lake dominated by cyanobacteria (Aphanizomenon flos-aquae).

机译：蓝藻（Aphanizomenon flos-aquae）为主的浅水富营养化湖泊的生态和水质动态。

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

This dissertation consists of two distinct chapters relating to ecological and water quality dynamics in Upper Klamath Lake, Oregon. In the first chapter, entitled: Effects of Nutrients, Consumers, and Physical Factors on Phytoplankton Biomass and Succession in a Shallow Hypereutrophic Lake, I present an examination of the seasonal and interannual patterns leading to dominance of large blooms of blue-green algae (Aphanizomenon flos-aquae) and their relationship with Daphnia (D. pulicaria) in shallow, hypereutrophic Upper Klamath Lake, Oregon. Contrary to trophic cascade theory, which predicts that systems dominated by large Daphnia should have low phytoplankton biomass, Upper Klamath Lake experiences extremely high biomass levels of both large-bodied Daphnia and algae. While light and temperature play a large role in initiation of the spring bloom, it also appears that continued seasonal succession toward Aphanizomenon dominance in Upper Klamath Lake depends not only upon low total inorganic nitrogen to soluble reactive phosphorus ratios (low TIN: SRP), but also on high SRP concentrations, and adequate levels of TN during periods when SRP is low and/or reduced light conditions retard nitrogen fixation. Although periods of Aphanizomenon dominance in Upper Klamath Lake occurred at both high and low levels of D. pulicaria, Daphnia's clear suppression of more edible algal competitors, regeneration of TIN and SRP, and apparent enhancement of low TIN:SRP ratios, may contribute to both dominance and biomass of Aphanizomenon.; In the second chapter, entitled: Chlorophyll as a Predictor of Elevated pH in a Hypereutrophic Lake: Estimating the Probability of Exceeding Critical Values for Fish Success Using Parametric and Nonparametric Models, I present a series of models to predict the probability of exceeding critical values of photosynthetically-elevated pH from algal biomass (chlorophyll a), in Upper Klamath and Agency Lakes, Oregon. As opposed to standard regression models, these probabilistic models reexpress the inherent spatial and temporal variance in the independent and dependent variables as the probability or frequency of conditions likely to be experienced by fish. Both parametric and nonparametric models performed similarly, showing that a 45% reduction in the probability of exceeding pH 9.5 (a likely sublethal limit) could be realized by reducing chlorophyll a from 200 to 100 {dollar}rmmu g Lsp{lcub}-1{rcub}{dollar}. This suggests that significant benefits to fisheries could be attained through restoration efforts that do not require a complete eutrophication reversal.
机译：本文由两个不同的章节组成，分别涉及俄勒冈州上克拉马斯湖的生态和水质动态。在标题为“营养素，消费者和物理因素对浅层富营养化湖泊中浮游植物生物量和演替的影响”的第一章中，我介绍了导致蓝绿色藻类大量繁殖（Aphanizomenon）占主导地位的季节和年际模式的研究。浅水，富营养化的上克拉马斯湖，俄勒冈州，它们与水蚤（D. pulicaria）的关系。与营养级联理论相反，该营养级联理论预测以大型水蚤为主导的系统应具有较低的浮游植物生物量，而上克拉马斯湖的大型水蚤和藻类均具有极高的生物量水平。虽然光和温度在春季开花的开始过程中起着重要作用，但似乎在上克拉马斯湖中，向Aphanizomenon优势的持续季节性演替不仅取决于总无机氮与可溶性活性磷的比率低（TIN：SRP低），而且还取决于在SRP浓度低和/或光照条件降低时，也需要高SRP浓度和适量的TN来阻止固氮。尽管上克拉马斯湖的Aphanizomenon优势期发生在高和低浓度的D. pulicaria上，但水蚤明显抑制了更多可食用的藻类竞争者，TIN和SRP的再生以及TIN：SRP比率低的明显增强，可能对这两者都有贡献。 Aphanizomenon的优势和生物量。在第二章标题为：叶绿素作为富营养化湖泊中pH升高的预测因子：使用参数模型和非参数模型估算鱼类成功超过临界值的可能性，我提出了一系列模型来预测超过临界值的可能性来自俄勒冈州上克拉马斯和Agency Lakes的藻类生物质（叶绿素a）的光合作用提高了pH值。与标准回归模型相反，这些概率模型将独立变量和因变量中固有的时空变化重新表达为鱼类可能经历的状况的概率或频率。参数模型和非参数模型的执行情况相似，表明通过将叶绿素a从200降低至100 {rm} g Lsp {lcub} -1 {，可以使pH超过9.5（可能的致死极限）的概率降低45％。 rcub} {dollar}。这表明，通过不需要完全富营养化逆转的恢复努力，可以为渔业带来重大利益。

著录项

  • 作者

    Kann, Jacob.;

  • 作者单位

    The University of North Carolina at Chapel Hill.;

  • 授予单位 The University of North Carolina at Chapel Hill.;
  • 学科 Biology Limnology.; Biology Ecology.; Biology Microbiology.; Biology Botany.
  • 学位 Ph.D.
  • 年度 1998
  • 页码 110 p.
  • 总页数 110
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生态学（生物生态学）;微生物学;植物学;
  • 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