Linkage between saline lakes and their catchments under climate change

人们普遍认为，盐湖的价值低于淡水，但在全球范围内，它们的体积几乎相等。气候对盐湖的影响是不成比例的大，因为他们通常浅的深度。盐湖的极端化学条件往往促进了由少数物种组成的专门社区，但那些茁壮成长的社区生产力很高。咸水湖周围的集水区通常是干旱的，因此陆地生产不发达，但可能严重依赖水生补贴，如新兴昆虫。因此，气候变化通过波动的水量和盐度对盐湖产生的影响可能会对更广泛的集水区产生随后的强烈影响。博戈里亚湖是肯尼亚的一个苏打湖，其简单的水生群落主要由一种节旋藻和一种摇蚊类Paratendipes（每月出现）组成，其三个不同的流域具有不同的环境特征，导致生物密度不同。大量鸟类，特别是火烈鸟，依赖前者，其他食虫鸟类物种以及具有保护价值的陆生无脊椎动物依赖后者。我们将使用博戈里亚湖作为一个模型系统，以解决3个目标。1为了确定过去发生了什么，我们将从3个不同的盆地取芯，通过分析摇蚊组合多样性和头囊密度来追溯过去的环境条件。我们的假设-随着时间的推移，湖泊体积的变化将影响盐度，并对藻类和摇蚊群落造成级联效应。2为了评估水生补贴对陆地消费者的影响，我们将测量每个流域的补贴“强度”，这些流域通常具有不同的摇蚊密度，作为衡量湖泊及其集水区之间联系的指标，假设补贴的强度将直接反映幼虫密度。这基本上是一个“空间换时间”的替代使用不同的幼虫密度作为环境条件的代理相对于目标1。3为了预测预测气候变化对这种联系的影响，我们将把目标1和2的数据与气候模型联合收割机起来。我们的预测-湖泊体积的减少将削弱连接从湖泊到集水区在未来。该项目福尔斯属于NERC在陆地表面（陆地和淡水）研究领域的科学主题范围。实现这三个目标将填补我们对盐湖相对于其旱地集水区的重要性的认识方面的一个重大空白。

There is a general perception that saline lakes are of less value than freshwaters yet they are of almost equal volume on a global scale. Climatic effects on saline lakes are disproportionately large because of their typically shallow depth. The extreme chemical conditions of saline lakes often promote specialised communities comprising few species but those that thrive are highly productive. Catchments surrounding saline lakes are typically arid and thus depauperate in terrestrial production but may rely heavily on aquatic subsidies e.g. emergent insects. Thus, climate change impacts on saline lakes via fluctuating volume and salinity may have subsequent, strong effects on the wider catchment. Lake Bogoria is a Kenyan soda lake with a simple aquatic community dominated by one alga Arthrospira and one chironomid Paratendipes (which has monthly emergences), and its three distinct basins have different environmental characteristics resulting in different densities of organisms. Large numbers of birds, particularly flamingo, rely on the former, and other insectivorous bird species, as well as terrestrial invertebrates of conservation value, rely on the latter. We will use Lake Bogoria as a model system to address 3 objectives. 1 To determine what has happened in the past we will take cores from the 3 distinct basins to hindcast past environmental conditions by analysing chironomid assemblage diversity and head capsule densities. Our assumption - changes in lake volume over time will have impacted upon salinity and caused cascade effects on algal and chironomid communities. 2 To assess how aquatic subsidies impact on terrestrial consumers we will measure the 'strength' of subsidy from each basin which typically has a different chironomid density as a measure of linkage between the lake and its catchment, hypothesising that the strength of subsidy will directly reflect larval density. This is essentially a 'space for time' substitution using the different larval densities as a proxy for environmental condition with respect to objective 1. 3 To forecast impacts of predicted climate change on such linkages we will combine the data from objectives 1 & 2 with climate models. Our prediction - lake volume reduction will weaken linkage from the lake to the catchment in the future. This project falls within the remit of NERC science themes in the area of land-surface (terrestrial and freshwater) research. Achieving these three objectives will close a significant gap in our knowledge of the importance of saline lakes with respect to their arid-land catchments.