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Ecology of the stalked diatom, Didymosphenia geminata, in Sierra Nevada streams.

机译：内华达山脉溪流中的茎状硅藻Didymosphenia geminata的生态。

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摘要

Demographic patterns of the freshwater stalked diatom, Didymosphenia geminata, have changed in the past twenty five years resulting in an increase in its spatial and temporal coverage in new and native streams. This proliferation has raised concerns because the causes and ecological consequences of extensive growth remain largely unknown. Three research projects were conducted in Sierra Nevada streams to gain insight into its ecophysiology and to determine if D. geminata forms ecologically disruptive blooms.;The first study establishes D. geminata distribution patterns in Sierra Nevada streams as it relates to ion chemistry and bedrock geology. In this study, it was shown that distribution patterns were positively correlated with a high percentage of Ca2+ and SO4 2-, and meta-sedimentary bedrock and negatively correlated with Mg 2+ concentrations and volcanic bedrock.;The second study presents results from nutrient limitation experiments using nutrient diffusing substrate and the following set of nutrient amendments including NO3- and PO4-, as well as Ca2+, SiO3-, HCO 3-, SO42-. Results show that N most often limits benthic algae growth in study streams (3/7) while SiO 3-, HCO3-, and SO4 2- limited growth in one study stream each. Results provide some insight into possible unique nutrient requirements for bloom development.;The third study addresses the extent to which nuisance growth is ecologically disruptive. Results show that nuisance growth can create ecologically disruptive blooms by reducing benthic macroinvertebrate grazer populations, reduce relative contributions of autochthonous carbon to higher trophic levels, and possibly reduce food quality at the trophic base of impacted stream. Additionally, this study also shows that ecologically disruptive conditions quickly diminish with the influence of an unaffected tributary stream.;These studies add to the growing body of knowledge pertaining to D. geminata ecophysiology and provide important insights into the magnitude and possible mechanisms of ecological disruptions.
机译：在过去的25年中，淡水茎状硅藻Didymosphenia geminata的人口统计学特征发生了变化，从而导致其在新的和原生河流中的时空覆盖范围增加。这种扩散引起了人们的关注，因为广泛增长的原因和生态后果仍然未知。在内华达山脉溪流中进行了三个研究项目，以了解其生态生理学并确定D.geminata是否形成破坏性生态的水华。第一项研究建立了内华达山脉溪流中的D.geminata分布模式，因为它与离子化学和基岩地质有关。 。这项研究表明，分布模式与高比例的Ca2 +和SO4 2-以及偏沉积的基岩呈正相关，与Mg 2+浓度和火山岩基呈负相关。;第二项研究提出了养分限制的结果使用营养物扩散基质和以下营养物补充剂（包括NO3-和PO4-，以及Ca2 +，SiO3-，HCO 3-，SO42-）进行的实验。结果表明，N最经常限制研究流中底栖藻类的生长（3/7），而SiO 3-，HCO3-和SO4 2-分别限制一个研究流中的底藻生长。结果为花bloom发育可能的独特养分需求提供了一些见识。；第三项研究探讨了滋扰性生长对生态造成破坏的程度。结果表明，令人讨厌的增长可通过减少底栖大型无脊椎动物食草动物种群，减少土生碳对较高营养水平的相对贡献，并可能降低受影响河流营养层的食物质量来创造破坏生态的水华。此外，这项研究还表明，在未受影响的支流的影响下，生态破坏条件迅速消失。这些研究增加了与双子叶蝉生态生理有关的知识，并为生态破坏的规模和可能机制提供了重要见解。 。

著录项

  • 作者

    Rost, Andrew L.;

  • 作者单位

    University of Nevada, Reno.;

  • 授予单位 University of Nevada, Reno.;
  • 学科 Biology Ecology.;Biology Limnology.;Biology Microbiology.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 111 p.
  • 总页数 111
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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