Determining the Impact of Nutrient, Organic Matter and Contaminant Fluxes From Melting Himalaya Glaciers on Downstream Ecosystems

地球上大约75%的淡水被锁在高山冰川和冰盖中，对未来气候的变化非常敏感。位于兴都库什喜马拉雅地区的冰川是全球山地冰川中最大的淡水储藏地，预计许多冰川将在本世纪退缩或消失。这些变化对供应14亿人口的亚洲主要河流的水流状况的影响正在得到更好的研究。然而，一个主要的研究缺口是喜马拉雅冰川融化对这些河流水质的影响，从而对下游生态系统健康的影响。这一点很重要，主要有两个原因。首先，人们经常发现冰川径流富含营养物质和生物可利用的有机物，这对维持下游生态系统和生态系统服务（例如渔业）可能很重要。然而，冰川集水区也在降雪中隔绝了大气中的污染物，并通过侵蚀从基岩中释放出微量金属，这些金属被释放到下游的水生生态系统中。虽然这些影响在其他地方（如阿拉斯加、欧洲阿尔卑斯山、格陵兰岛）得到了很好的研究，但冰川融水在形成喜马拉雅水生生态系统的形式和功能方面的作用是一个新的领域。它需要与喜马拉雅地区的东道国密切合作，因为实地地点的偏远性质和政府许可的要求。这个博士项目旨在采用新的原位化学传感技术，这些技术是通过以前的NERC资助开发的（发现资助“DELVE”，加的夫大学Liz Bagshaw博士和国家海洋学中心Alex Beaton博士），结合喜马拉雅冰川径流的有机物质、无机营养物质的化学分析。Jemma Wadham, Richard Evershed)和污染物（Laura Robinson教授）。此外，还将在研究的河流集水区进行现场生物测量和生物分析，以推断出口的营养物/有机物对浮游生物群落的生物可利用性，以及污染物进入生物群的情况（Alex Anesio教授）。该项目将与贾瓦哈拉尔·尼赫鲁大学（JNU：新德里）的Al. Ramanathan教授合作进行，他在过去15年里在印度喜马拉雅地区开发了几个冰川场。该项目的具体目标是确定对喜马拉雅河流域径流中营养物质和有机物（目标1）以及毒素（例如金属、微塑料）（目标2）的流量的控制，这些径流具有对比鲜明的冰川覆盖。它将继续确定喜马拉雅河水质对下游浮游生物群落的影响（目标3）。这将导致对喜马拉雅冰川消融对下游河流水质和全球变暖中水生生态系统影响的开创性评估。

Around 75 % of the Earth's freshwater is locked up in mountain glaciers and ice sheets and is highly sensitive to changes in future climate. Glaciers located within the Hindu-Kush Himalayan region represent the largest store of freshwater held in mountain glaciers globally, and many are predicted to either retreat or disappear this century. The impacts of these changes upon the flow regimes major Asian rivers, which supply > 1.4 billion people, are becoming better studied. However, a major research gap is the impact of Himalayan glacier melting upon on the quality of water in these rivers, and thus on downstream ecosystem health. This is important for two main reasons. First, glacier runoff is often found to be enriched in nutrient and bioavailable organic matter, which may be important in sustaining downstream ecosystems and ecosystem services (e.g. fisheries). However, glacial catchments also sequester pollutants from the atmosphere in snowfall and release trace metals from bedrock via erosion, which are released to downstream aquatic ecosystems. While these impacts are well researched elsewhere (e.g. Alaska, European Alps, Greenland), the role of glacial meltwater in shaping the form and function of Himalayan aquatic ecosystems is a new field. It requires close cooperation with Himalayan host nations because of the remote nature of the field sites and requirement for governmental permission. This PhD project aims to employ novel in situ chemical sensing technologies developed via previous NERC funding (Discovery Grant "DELVE", Dr Liz Bagshaw, University of Cardiff and Dr Alex Beaton, National Oceanography Centre), in combination with chemical profiling of Himalayan glacier runoff for organic matter, inorganic nutrients (Profs. Jemma Wadham, Richard Evershed) and contaminants (Prof. Laura Robinson). It will be complemented by in situ biological measurements and bio-assays in the study river catchments to infer the bioavailability of exported nutrients/organic matter to planktonic communities and any incorporation of contaminants into biota (Prof. Alex Anesio). The project will be undertaken in collaboration with Prof. Al. Ramanathan at Jawaharlal Nehru University (JNU: New Delhi) who has developed several glacier field sites in the Indian Himalaya over the last 15 years. The project will specifically aim to determine the controls upon the fluxes of nutrient and organic matter (Objective 1) and of toxins (e.g. metals, micro plastics) (Objective 2) in runoff from Himalayan river catchments with contrasting glacial cover. It will go on to determine the impact of Himalayan river water quality upon downstream planktonic communities (Objective 3). This will result in a ground-breaking assessment of the impact of a deglaciating Himalaya upon downstream river water quality and aquatic ecosystems in warming world.