Quantifying annual cycles of macronutrient fluxes and net effect of transformations in an estuary: Their responses to stochastic storm-driven events

量化河口常量营养素通量的年度周期和转化的净效应：它们对随机风暴驱动事件的响应

• 批准号: NE/J012025/1
• 负责人: Jan Kaiser
• 金额: $ 2.82万
• 依托单位: University of East Anglia
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FJ012025%2F1
• 关键词: Quantifying; annual; cycles; macronutrient; fluxes

Estuaries are more than simply areas of mud and marsh that represent the transition zone between rivers and the ocean. They play a vital role in our economy as sites of leisure and commercial activities, such as fishing and boating. In addition, they are important nursery grounds for many species of economically important fish that later migrate to the open sea. As approximately 40% of the world's population live within 100 km of the coast, estuaries are also some of the most vulnerable sites for impact from man's activities. Not only can they suffer from activities occurring within the estuary itself, but they also mark the point where pollutants gathered by rivers from large areas of the interior can accumulate.One of the major pollution concerns in estuaries arises from the excess river borne concentrations of phosphate and nitrate. These can be derived from a variety of sources, such as run off from fertilised fields and discharge (accidental or purposeful) from sewage treatment plants. Regardless of their source, they can cause severe problems, such as stimulating the growth of excess algal growth that can deplete the water in oxygen and causing widespread fish kills, or causing the growth of poisonous algal species (red tides) that cause shell fish fisheries to be closed. Although this problem has been recognised for some time, and monitoring activities by bodies such as the Environment Agency and water companies play an important role in keeping pollution in check, there are still major gaps in our knowledge. In particular, it is apparent that a large proportion of the flux of nitrate and phosphate are delivered to estuaries by sudden storm events, but most monitoring takes place at fixed times that are spaced too far apart to capture these events. This is a major gap in our knowledge that will become more important as the intensity and frequency of storms are likely to increase due to climate change. Additionally, the phosphate and nitrate load of rivers can take many forms - dissolved and particulate, organic and inorganic - and relatively little is known about the concentrations of these different forms varies throughout the seasons and during storm events. Only if we are able to fully understand these processes will we be able to take the necessary steps to identify and control polluting sources of nitrate and phosphate to estuaries.Our research seeks to address this gap in our knowledge by carrying out detailed monitoring of the many forms of phosphate and nitrate that enter Christchurch Harbour estuary (Dorset) from both the rivers and the sea over the course of a year. We will be using state-of-the-art technology (much of it developed by ourselves) that will allow us to monitor they key parameters at intervals of every 30 minutes. Hence, we will be able to capture the effects of sudden and short-lived storms that have eluded previous studies and routine monitoring practices. We will then use the results of our study to examine how these sudden storm events affect the distribution of phosphate and nitrate within the estuary. In particular, we will examine what happens when sediments are stirred up in the estuary by storms - do they remove or add phosphate and nitrate to the system? We will also examine the effects of these sudden storms on the biological activity in the estuary. Again, do they increase or decrease the growth of algae, and what difference is there if the storm happens in the summer or the winter?The various threads of our study will be drawn together into a powerful statistical model that will allow us to better understand the transfer of phosphate and nitrate from rivers, through estuaries and into the coastal seas, and the role that storms play in this process. Our results will then allow policy makers to make more informed decisions about how we can seek to reduce pollution of estuaries by nitrate and phosphate.

河口不仅仅是代表河流与海洋之间过渡区的泥土和沼泽地区。他们在我们的经济中发挥了至关重要的作用，作为休闲和商业活动（例如钓鱼和划船）。此外，对于许多经济上重要的鱼来说，它们是随后迁移到公海的重要苗圃。由于大约40％的世界人口居住在海岸100公里以内，因此河口也是人类活动影响的一些最脆弱的地点。它们不仅可以遭受河口本身发生的活动的困扰，而且还标志着从内部大区域收集的河流收集的污染物可以累积的地步。河口的主要污染问题之一是由于过量的河流磷酸盐和硝酸盐的河流浓度而引起的。这些可以源自多种来源，例如从受精场和污水处理厂的出院（意外或有目的）逃脱。不管它们的来源如何，它们都会引起严重的问题，例如刺激藻类过量生长的生长，可以耗尽氧气中的水并引起广泛的鱼类杀死，或者导致有毒藻类物种的生长（红色潮汐），从而导致壳的鱼类渔业被关闭。尽管这个问题已被确认了一段时间，并且对环境机构和水公司等机构的监视活动在控制污染方面发挥了重要作用，但我们的知识仍然存在重大差距。特别是，很明显，突然的暴风雨事件将很大一部分的硝酸盐和磷酸盐通量传递到河口，但是大多数监测发生在固定时间间隔太远以无法捕获这些事件的固定时间进行。在我们的知识上，这是一个主要差距，随着气候变化导致风暴的强度和频率可能会增加，这将变得越来越重要。此外，河流的磷酸盐和硝酸盐负荷可以采取多种形式 - 溶解和颗粒物，有机和无机性 - 对于这些不同形式的浓度在整个季节和暴风雨事件中都有不同的了解。只有我们能够充分理解这些过程，我们才能采取必要的步骤来识别和控制硝酸盐和磷酸盐的污染源。我们将使用最先进的技术（大部分由我们自己开发），这将使我们能够每30分钟的时间间隔监视它们的关键参数。因此，我们将能够捕获突然和短暂的风暴的影响，这些风暴避免了以前的研究和常规监测实践。然后，我们将使用研究结果来研究这些突然的暴风雨事件如何影响河口内磷酸盐和硝酸盐的分布。特别是，我们将检查当河口在河口中搅动沉积物时会发生什么 - 它们是否去除或添加磷酸盐和硝酸盐？我们还将研究这些突然风暴对河口生物学活性的影响。同样，它们会增加或减少藻类的生长吗？如果暴风雨在夏季或冬季发生？我们的研究的各种线索将被吸引到一个强大的统计模型中，这将使我们能够更好地理解磷酸盐和硝酸盐从河流，通过河口，河口的转移，通过埃斯塔伊尔人和沿海海洋中的角色在这一过程中起着风暴的作用。然后，我们的结果将使决策者能够就我们如何寻求减少硝酸盐和磷酸盐对河口的污染做出更明智的决定。