Detection, Attribution and Solutions for Increasing Aluminium in Freshwaters

铝(Al)从土壤向淡水中释放的增加是慢性陆地酸化最具毒性的影响之一，也是20世纪80年代欧洲和美国本土鲑鱼种群灭绝的原因。人们普遍认为，随着1990年代酸排放立法的成功，铝问题得到了解决；淡水酸化的有害影响被证明是可逆的，淡水中的铝水平下降。然而，我们的实验室发现，自2000年以来，北美东部和欧洲的湖泊和河流中的铝水平普遍上升，其中瑞典东南部和南欧是热点地区。我们对淡水化学中这种不可预测的变化的确认揭示了一个紧迫的国际问题，不仅是对目前正在下降到接近灭绝水平的鲑鱼种群，而且对森林生态系统生产力、生物多样性、水处理以及潜在的人类健康也是如此。我的研究方案将使用数据库和实地研究相结合的方式，在北美和欧洲的500多个实地地点评估铝趋势的程度和原因，从而评估酸化的风险。我们将开发新的预测方法，以确定哪些集水区的铝水平可能较高并不断上升。将在年度间、季节性和事件尺度上对主要机制进行评估。我们将利用长期水蒸气化学数据库的现场和统计分析来检验我们关于铝水平上升原因的假设，并开发新的理论模型来解释这种意想不到的趋势。我们还将根据实地实验绘制出铝的毒性形式的范围图，以确定湖泊和河流的化学物质在哪里以及在什么条件下超过铝的毒性阈值。最后，我们将测试通过增强风化作用向森林土壤输送钙和碱度的方法的有效性：将碎石涂抹到森林土壤上。评估不同类型岩石应用的作用，以及这种方法降低铝水平的能力。由于钙限制是北美东部和欧洲普遍存在的问题，而且北美洲的集水区是测试/监测缓解铝战略的极好的模式系统，我的研究计划的贡献将产生国际影响。我的研究计划将支持包括2名博士、2名硕士和4名本科生在内的几名HQP的培训。

Increased release of aluminium (Al) from soils to freshwaters is one of the most toxic impacts of chronic terrestrial acidification, and has been responsible for the extirpation of native salmon populations in Europe and the USA in the 1980s. The Al problem was widely considered solved following the success of acid emission legislation in the 1990s; the harmful effects of freshwater acidification were shown to be reversible and Al levels in freshwaters decreased. However, our laboratory has discovered that there are widespread increases in Al levels in lakes and rivers since 2000 across eastern North America and Europe, with hotspots in southeastern Sweden and NS. Our identification of this unpredicted change in freshwater chemistry has illuminated an urgent international issue, not only for salmon populations that currently are declining to near extirpation levels, but forest ecosystem productivity, biodiversity, water treatment and, potentially, human health. My research programme will use a combination of database and field studies to assess the extent and causes of Al trends, and hence risk from acidification, in over 500 field sites across North America and Europe. We will develop new predictive approaches for determining which catchments are likely to have high and increasing Al levels. Key mechanisms will be evaluated with respect to drivers of Al both on an inter-annual, seasonal and event scales. We will employ field and statistical analysis of long-term stream chemistry databases to test our hypotheses on the causes of increasing Al levels and to develop new theoretical models to explain this unexpected trend. We will also map the extent of the toxic form of Al, based on field experiments across NS to determine where and in what conditions the lakes and river chemistry exceeds toxic thresholds for Al. Finally, we will test the efficacy of methods of delivery of calcium and alkalinity to forest soils through enhanced weathering: applying crushed rock onto forest soils. evaluating the role of different types of rock application, and the ability of this method to reduce Al levels. Since calcium limitations are a widespread problem across eastern North America and Europe, and catchments in NS are an excellent model system for testing/monitoring strategies for Al mitigation, contributions from my research programme will have international impact. My research program will support the training of several HQP including 2 doctoral, 2 masters and 4 undergraduate students.