RUI: Using a Paleolimnological Approach to Assess the Interactive Effects of Acidic Deposition and Eutrophication on Softwater Lakes

RUI：使用古湖泊学方法评估酸性沉积和富营养化对软水湖的相互作用影响

• 批准号: 9615062
• 负责人: Peter Siver
• 金额: $ 30.89万
• 依托单位: Connecticut College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-15 至 2001-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9615062&HistoricalAwards=false
• 关键词: RUI; Using; Paleolimnological; Approach; Assess

ABSTRACT SIVER (96-15062) Acid deposition eutrophication remains two of the most adverse processes effecting the health of aquatic resources today. Even though much research on acid deposition and eutrophication has occurred over the last two decades, scientists are just beginning to realize the importance of the interactive effects of both processes on the condition of surface waters. Much of the research on acid deposition over the last twenty years has focused on terrestrial processes generating alkalinity in the watershed and, more recently, on the role of sulfur biogeochemistry on within-lake alkalinity generation. However, this heavy emphasis on alkalinity generation has sometimes obscured the roles and interactions of other elements and processes in determining the long term effects of acidic deposition. Likewise we understand many of the consequences of entrophication, but are just now realizing that this process also alters the sulfur cycle and changes the sedimentary sulfur storage record. Although not completely understood, it is clear that the effects of acid deposition and eutrophication in controlling the condition and subsequent degradation of surface waters are coupled through the biogeochemical cycling of sulfur, iron, and carbon, and the internal loading of phosphorus from the sediments. A key to understanding these linkages resides in the chemical and biotic signals that are archived in lake sediments. To understand the interaction between acid deposition and eutrophication on the sulfur cycle of lakes, and on the chemical signals we measure in sediments, we need to examine biogenic markers in the sediment, which respond uniquely to either eutrophication or acidification. It is now relatively common to use microscopic algal remains to form inference models that are used to reconstruct historical changes in the chemical structure of individual lakes. Such a paleolimnological method has been successfully utilized to reconstruct pH and trophic status. An independent tracking of changes in historical pH and trophic status relative to alterations in the burial of sulfur will help elucidate the role that eutrophication plays in explaining why some low alkalinity lakes in the northeast have acidified as a result of acid deposition, while others have not. The primary focus of this project will be to utilize a paleolimnological method in order to elucidate the interaction of acidification and eutrophication on sulfur biogeochemical cycling in southern New England lakes. We propose to utilize scaled chrysophyte remains in order to form inference models that will be used to reconstruct historical changes in the pH and trophic status of lakes, and simultaneously analyze changes in the storage of sulfur, iron and carbon, from the same waterbodies. The study will focus on changes over the last ca. 150 years, compare drainage (Connecticut lakes) and seepage (Cape Cod lakes) lakes, and include waterbodies that span relatively wide contemporary trophic and pH gradients. The project will effectively utilize and continue to add to large paleolimnological data sets from both geographic regions.

摘要Siver（96-15062）酸沉积富营养化仍然是影响当今水生资源健康的两个最不利的过程。尽管在过去的二十年中已经对酸性沉积和富营养化进行了许多研究，但科学家才刚刚开始意识到这两种过程对地表水状况的交互作用的重要性。在过去的二十年中，大部分关于酸沉积的研究集中在陆地过程中，产生了流域中碱度的陆地过程，最近，硫磺生物地球化学在湖内碱性内产生中的作用。然而，对碱度产生的这种重视有时掩盖了其他元素和过程在确定酸性沉积的长期影响中的作用和相互作用。同样，我们了解了作品的许多后果，但是现在才意识到此过程也会改变硫周期并改变沉积硫储存记录。尽管尚未完全理解，但很明显，酸沉积和富营养化在控制地表水的状况和随后降解中的影响通过硫，铁和碳的生物地球化学循环以及磷中的磷中的内部负载耦合。 了解这些联系的关键在于存档在湖泊沉积物中的化学和生物信号中。为了了解湖泊硫周期上的酸沉积与富营养化之间的相互作用，以及在沉积物中测量的化学信号上，我们需要检查沉积物中的生物源标记物，这些标志物对富营养化或酸化的响应是独特的。现在使用微观藻类遗物形成用于重建单个湖泊化学结构的历史变化的推理模型相对常见。这种古学方法已成功地用于重建pH和营养状态。相对于硫磺埋葬的改变，对历史pH和营养状况的变化的独立跟踪将有助于阐明富营养化在解释为什么东北某些低碱度湖泊在酸性下酸化的作用，而另一些则没有。 该项目的主要重点是利用一种古学方法，以阐明新英格兰南部湖泊中硫化生物地球化学循环的酸化和富营养化的相互作用。我们建议利用缩放的金属植物残留物，以形成推理模型，这些模型将用于重建湖泊的pH和营养状态的历史变化，同时分析了来自相同水体的硫，铁和碳的存储变化。该研究将重点放在最后一个CA的变化上。 150年，比较排水湖（康涅狄格州湖泊）和渗水（Cape Cod Lakes）湖泊，并包括横跨现代营养和pH梯度的水体。该项目将有效地利用并继续增加来自两个地理区域的大型古学数据集。