Sediment-Water Column Exchange of Nutrients in Coastal and Shelf-Sea Waters

沿海和陆架海水中的沉积物-水柱交换营养盐

• 批准号: NE/F003293/1
• 负责人: Gary Fones
• 金额: $ 24.05万
• 依托单位: University of Portsmouth
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF003293%2F1
• 关键词: Sediment; Water; Column; Exchange; Nutrients

Over the last 50 years concentrations of the nutrient elements nitrogen, phosphorus and silicon entering coastal seas such as the North Sea have increased due to Human influences. Coastal seas are very important in controlling the cycling of these elements essential to life on Earth, particularly as nearly a third of the world's ocean primary production takes place in these regions. Primary production is the growth of phytoplankton - floating microscopic plants also known as algae. Algal growth, which is fuelled by these nutrient elements, takes up carbon dioxide from the atmosphere, thus helping to regulate atmospheric concentrations of this greenhouse gas. Until recently, it was thought that the North Sea receives enough nutrients from rivers and the atmosphere to sustain the large phytoplankton blooms that are observed there. At the end of spring; the phytoplankton have used up nearly all the available nutrients in the water column and they die and sink to the sea bed. It was thought the regeneration of nutrient levels occurring over the proceeding winter period mainly from rivers and the oceans was sufficient to start the cycle again in the spring. However, it has been discovered that the actual amount coming in from rivers and surrounding seas is less than that needed to start the cycle again in the spring. It has now been hypothesised that a sediment source released during the stirring up of sediments (i.e. through resuspension of the surface layers of the sea bed) elevates the concentration of nutrients in the water to levels high enough to stimulate large phytoplankton blooms in the spring when light levels also favour algal growth. Sediment resuspension can be caused by strong winds, waves, tides and also by trawling gear used in fishing. In this proposed study, we will investigate the impact of sediment resuspension on nutrients and determine if it is either a source (puts nutrients from the sediment into the water) or a sink (takes nutrients out of the water into the sediment). To do this study we will take part in research cruises to 3 areas of the North Sea where we will place equipment on the sea bed to simulate the stirring of the sediments. We will collect data on sediment resuspension and nutrient release as well as make measurements of background transfer of nutrients without resuspension. We will also collect sediment to study the same processes in the laboratory under more controlled conditions. The data will be used with computer models of this system to test the models and help to provide better predictions of the impact of resuspension events on nutrients in the water column. The results of the proposed project will provide us with a better understanding of the role of nutrients and sediment interactions in coastal and shelf seas and the influence this has on primary production. Consequently, this work will contribute to quantifying the role of resuspension in controlling the fate of nutrients in regional and global budgets. The gathered data will give modellers who produce mathematical descriptions of these systems, additional tools and information to help effectively manage the quality of coastal waters.

在过去的50年中，由于人类的影响，氮，磷和硅进入沿海海域（例如北海）的浓度增加了。沿海海洋对于控制这些对地球生命必不可少的元素的循环非常重要，尤其是世界上近三分之一的海洋初级生产发生在这些地区。初级生产是浮游植物的生长 - 浮动微观植物也称为藻类。这些营养元素助长了藻类生长，从大气中吸收二氧化碳，从而有助于调节这种温室气体的大气浓度。直到最近，人们认为北海还从河流和大气中获得足够的营养，以维持那里观察到的大型浮游植物。在春天结束；浮游植物已经用完了水柱中几乎所有可用的营养物质，它们死亡并沉入海床。人们认为，在冬季进行的养分水平的再生主要来自河流，海洋足以在春季再次开始周期。但是，已经发现，从河流和周围的海洋中进出的实际数量远小于春季重新开始周期所需的实际数量。现在已经假设，在沉积物中释放的沉积物源（即，通过重悬于海床的表面层）将水中的养分浓度提升到足够高的水平，以刺激春季春季盛开的大型浮游植物，当光水平也有利于藻类生长。沉积物重悬于强风，波浪，潮汐以及捕捞中使用的齿轮。在这项拟议的研究中，我们将研究沉积物重新悬浮对养分的影响，并确定它是来源（将养分从沉积物中放入水中）还是水槽（将养分从水中取出沉积物）。为了完成这项研究，我们将参加研究巡游，前往北海的3个地区，在那里我们将设备放在海床上，以模拟沉积物的搅动。我们将收集有关沉积物重悬和养分释放的数据，以及对养分的背景转移而无需重悬的测量。我们还将在更受控的条件下收集沉积物以研究实验室中的相同过程。数据将与该系统的计算机模型一起使用，以测试模型，并有助于更好地预测重悬事件对水柱中养分的影响。拟议项目的结果将使我们更好地了解沿海和货架海中营养和沉积物相互作用的作用，以及这对初级生产的影响。因此，这项工作将有助于量化重悬在控制区域和全球预算中养分命运方面的作用。收集的数据将使对这些系统，其他工具和信息的数学描述的建模者有效地管理沿海水域的质量。

项目成果

In situ flume measurements of resuspension in the North Sea

北海再悬浮的原位水槽测量

• DOI: 10.1016/j.ecss.2011.05.026
• 发表时间: 2011
• 期刊: Estuarine, Coastal and Shelf Science
• 作者: Thompson C

The application of Diffusive Gradients in Thin Films (DGT) for improved understanding of metal behaviour at marine disposal sites.

• DOI: 10.1016/j.scitotenv.2016.09.183
• 发表时间: 2017
• 期刊: The Science of the total environment
• 作者: Ruth Parker;T. Bolam;J. Barry;C. Mason;S. Kröger;L. Warford;B. Silburn;D. Sivyer;S. Birchenough;A. Mayes;G. Fones