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

地球上约75%的淡水被困在山区冰川和冰盖中，对未来气候的变化高度敏感。位于兴都库什喜马拉雅地区的冰川是全球最大的山地冰川淡水储存库，预计许多冰川将在本世纪消退或消失。这些变化对亚洲主要河流水流系统的影响正在得到更好的研究，这些河流供应着14亿人。然而，一个主要的研究空白是喜马拉雅冰川融化对这些河流的水质的影响，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，冰川径流常常被发现富含营养物质和生物可利用的有机物质，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，冰川集水区也会在降雪时将污染物从大气中隔离出来，并通过侵蚀从基岩中释放出痕量金属，然后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，但冰川融水在塑造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。这需要与喜马拉雅东道国密切合作，因为这些场地地处偏远，需要政府许可。这一博士项目旨在使用通过以前的NERC资助(发现赠款“DELVE”、加的夫大学的Liz Bagshaw博士和国家海洋学中心的Alex Beaton博士)开发的新的现场化学传感技术，并结合喜马拉雅冰川径流的有机物质、无机营养物质的化学剖面(教授。杰玛·沃德姆、理查德·埃弗谢德)和污染物(劳拉·罗宾逊教授)。它将得到研究河流集水区的现场生物测量和生物分析的补充，以推断向浮游生物群落输出的营养物质/有机物质的生物可用性以及生物群中污染物的任何并入情况(Alex Anesio教授)。该项目将与Al教授合作进行。拉马纳坦在贾瓦哈拉尔·尼赫鲁大学(JNU：新德里)工作，在过去的15年里，他在印度喜马拉雅开发了几个冰川场地。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)和毒素(例如金属、微塑料)(目标2)通量的控制。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)。这将导致对正在变暖的世界中喜马拉雅冰川消融对下游河流水质和水生生态系统的影响进行开创性的评估。

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.