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首页> 外文学位 >Impact Of Algal Blooms And Reservoirs On Nutrients And Dissolved Organic Matter Dynamics In The Hypereutrophic Klamath River, USA.
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Impact Of Algal Blooms And Reservoirs On Nutrients And Dissolved Organic Matter Dynamics In The Hypereutrophic Klamath River, USA.

机译：在美国富营养化的克拉马斯河，藻华和水库对营养物和溶解有机物动力学的影响。

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摘要

Many of our global freshwater resources are currently impaired or threatened by impoundments, eutrophication, and harmful algal blooms as a result of increasing population, resource use, and climate change. To better protect, manage, and restore our freshwaters, it is essential to study the ecological effects of impoundments and impairments (e.g. nutrient enrichment, algal blooms, etc.). The Klamath River, located in Oregon/California of the Pacific Northwestern U.S.A., is highly impounded (six reservoirs), hypereutrophic, and experiences large seasonal algal blooms. Dam removal is currently being considered on the Klamath River, and therefore an understanding of current conditions is critical to making predictions under alternative management scenarios. The objective of this work was to examine how reservoirs, river reaches, and algal blooms in the Klamath River affect spatiotemporal patterns in water quality, biogeochemical processing, and the fate and transport of nutrients and organic matter. These objectives were addressed by studies conducted for two years along 184 km of the Klamath River. The summer algal bloom had major effects on water quality conditions and available nutrients (e.g. low dissolved oxygen, high pH, nutrient addition via N-fixation, labile organic matter), and was the major driver of biogeochemical processes within the upper portion of the river that is highly impacted by five reservoirs. The role of reservoirs in propagating effects of the algal bloom to downstream reaches shifted depending on the reservoir location and time of year. Reservoirs served as sources or sinks of materials during different times of the year. The uppermost reservoirs were more strongly influenced by algal blooms and tended to export higher nutrients and algal-derived organic matter during and following the bloom, whereas downstream reservoirs tended to trap and process these materials, resulting in export of lower nutrient water comprised of more highly degraded, recalcitrant organic matter. Spatial differences in water quality, nutrients, and organic matter along the longitudinal gradient of the river were greater during and following the algal bloom, and reduced during months of higher flow and reduced biological activity. Linked reservoirs and river reaches were important in the cycling and export of nutrients, particularly nitrogen. Nitrogen cycling in the upper Klamath River was rapid; high amounts of algal nitrogen-fixation, followed by mineralization and export of algal-based nitrogen to downstream river reaches produced some of the most rapid nitrification rates observed in large river systems. These processes appear to be highly active and dynamic over a variety of temporal scales, and likely have strong implications for the structure and function of local and downstream aquatic communities. This study illuminates the importance of algal blooms and the role of impoundments in driving water quality, nutrient, and organic matter dynamics and emphasizes the importance in understanding how these effects evolve over space and time, especially in the context of predicting alternative management and restoration scenarios (i.e. dam removal).
机译：由于人口，资源使用和气候变化的增加，当前许多全球淡水资源受到蓄水，富营养化和有害藻华的损害或威胁。为了更好地保护，管理和恢复我们的淡水，必须研究蓄水和蓄水的生态效应（例如营养物质富集，藻华等）。克拉马斯河位于美国西北太平洋的俄勒冈州/加利福尼亚州，蓄水量大（六个水库），富营养化，并且季节性海藻大量繁殖。目前正在考虑在克拉马斯河上拆除大坝，因此，了解当前状况对于在替代管理方案下进行预测至关重要。这项工作的目的是研究克拉马斯河的水库，河道和藻华如何影响水质，生物地球化学处理以及养分和有机质的命运和运输的时空格局。通过在克拉马斯河184公里处进行了为期两年的研究，实现了这些目标。夏季藻华对水质状况和可利用的养分（例如低溶解氧，高pH，通过固氮作用添加养分，不稳定的有机质）产生重大影响，并且是河流上游生物地球化学过程的主要驱动力受五个水库的影响很大。储层在藻华向下游传播的作用中的作用随储层位置和一年中的时间而变化。在一年中的不同时间，水库用作材料的来源或汇。最上层的水库受到藻华的影响更大，并且在开花期间和之后倾向于输出更高的养分和藻类衍生的有机物，而下游的水库则倾向于捕集和加工这些物质，从而导致较低的营养水出口量更大。降解的顽固有机物。在藻类开花期间和之后，水质，养分和有机质沿河的纵向梯度的空间差异更大，而在高流量和生物活性降低的月份中，空间差异减小。连接的水库和河段对养分尤其是氮素的循环和输出很重要。克拉马斯河上游的氮循环很快。大量的藻类固氮，随后矿化并向下游河道输出藻类氮，这在大型河流系统中产生了某些最快的硝化速率。这些过程似乎在各种时间尺度上都是高度活跃和动态的，并且可能对当地和下游水生群落的结构和功能产生重大影响。这项研究阐明了藻华的重要性以及蓄水在驱动水质，营养和有机物动力学方面的作用，并强调了理解这些影响如何随时间和空间演变的重要性，尤其是在预测替代管理和恢复方案的背景下（即拆除大坝）。

著录项

  • 作者

    Oliver, Allison Anne.;

  • 作者单位

    University of California, Davis.;

  • 授予单位 University of California, Davis.;
  • 学科 Biology Ecology.;Hydrology.;Biogeochemistry.
  • 学位 Ph.D.
  • 年度 2013
  • 页码 117 p.
  • 总页数 117
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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