Developing novel molecular tools for characterising food web responses to climate change

开发新颖的分子工具来表征食物网对气候变化的反应

• 批准号: 1659751
• 金额: --
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1659751
• 关键词: Developing; novel; molecular; tools; characterising

The aim of this project is to quantify the effects of global warming on food web structure of freshwater ecosystems. I will be studying the strength of the links, and the direction of energy flows of several different food webs across a temperature gradient. To address these key ecological questions I will test novel molecular techniques such as next generation sequencing (NGS) which will be used to match more traditional food web approaches. In particular, it is possible to identify species by sequencing part of their genetic code, and comparing it to a database without referring to their morphological traits. The use of such techniques gives us extremely valuable information, in fact: we can detect the presence of cryptic species (I) which are morphologically identical, but have distinct genetic traits, also, identify early instar larvae (II) which are impossible to distinguish at such stage, but it can be useful also in terms of damaged specimens (III). Moreover, I will take advantage of new mesocosm facilities at Silwood park in order to predict the effects of warming on the stability and structure of freshwater ecosystems, in particular we are aiming to heat mesocosms by 4C and 7C which is the degree of heat that we expect to encounter at our latitudes, and high latitudes, respectively, in the following century. The principle is the same adopted in a long-term mesocosm study in Dorset (UK) where we already have an exceptionally detailed data of the community composition and size-spectra of both the pelagic and benthic food webs, but with a higher replicability (96 mesocosms in Silwood park) of treatments. This project will also have a consistent fieldwork component which will take place in five different geothermal sites along the ring of fire in the Northern hemisphere; these will include: Iceland, Greenland, Alaska, Kamchatka, and Svalbard. These arctic sentinel systems will act as a refuge for species migrating polewards due to increase global warming. Moreover, it will be particularly interesting to study these systems as high latitudes surface temperatures are predicted to increase up to 7.5C in the following century (IPCC, 2014). Understanding structure and dynamics of these food webs will be fundamental to address future issues which will appear at our latitudes. The beauty of such geothermal systems is that they almost act as outdoor laboratories, in fact, streams have similar chemical composition, and only differ by water temperature. The Icelandic site (Hengill) has been studied for several years, and we now have a detailed description of its food web. This will allow us to apply NGS techniques into a well described food web, where we expect to match data collected from traditional food web analysis, particularly in terms of species richness and abundances. In addition to this, I will try to describe some of the links yet poorly understood in food web analysis, such as the diet of some groups (e.g. suctorial predators) which represent a missing link within the food web. In order to explore these "missing links", I will apply NGS techniques to analyse the diet of predators not visible from gut content analysis, this will allow us to add valuable information in terms of food web structure. The Icelandic site will act as a platform where we will be testing methods, and experiments which will be then applied to all the other geothermal sites. Keeping these methods consistent will be crucial, in order to investigate and disentangle differences and potential generalities which will emerge across the different sites. In particular, we expect warming to produce similar patterns in ecosystems with a wide difference of species. Finally, I will investigate generalities between natural systems and mesocosms, as previous studies already support a consistent thermal response in relation to ecosystem respiration between the Icelandic streams and the UK mesocosms.

该项目的目的是量化全球变暖对淡水生态系统食物网结构的影响。我将研究这些联系的强度，以及几个不同食物网在温度梯度下的能量流动方向。为了解决这些关键的生态问题，我将测试新的分子技术，如下一代测序（NGS），这将用于匹配更传统的食物网方法。特别是，可以通过对其遗传密码的一部分进行测序来识别物种，并将其与数据库进行比较，而无需参考其形态特征。使用这种技术给我们提供了非常有价值的信息，事实上：我们可以检测到形态上相同但具有不同遗传特征的神秘物种（I）的存在，还可以识别在这个阶段无法区分的早期幼虫（II），但它也可以用于受损标本（III）。此外，我将利用Silwood公园新的中型生态系统设施来预测变暖对淡水生态系统稳定性和结构的影响，特别是我们的目标是将中型生态系统加热4 C和7 C，这是我们预计在下一个世纪在我们的纬度和高纬度地区分别遇到的热量。该原则是相同的，在多塞特（英国）的长期围隔研究中，我们已经有一个非常详细的数据的群落组成和大小谱的浮游和底栖食物网，但具有较高的可复制性（96围隔在Silwood公园）的治疗。该项目还将有一个一致的实地考察部分，将在北方半球火环沿线沿着五个不同的地热地点进行;这些地点包括：冰岛、格陵兰、阿拉斯加、堪察加和斯瓦尔巴。由于全球变暖，这些北极哨兵系统将成为物种向极地迁移的避难所。此外，研究这些系统将特别有趣，因为高纬度地表温度预计将在下一个世纪增加到7.5 ℃（IPCC，2014年）。了解这些食物网的结构和动态将是解决未来将出现在我们纬度的问题的基础。这种地热系统的美妙之处在于，它们几乎充当了户外实验室，事实上，溪流具有相似的化学成分，只是水温不同。冰岛遗址（Hengill）已经被研究了好几年，我们现在对它的食物网有了详细的描述。这将使我们能够将NGS技术应用到一个描述良好的食物网中，我们希望在那里与从传统食物网分析中收集的数据相匹配，特别是在物种丰富度和丰度方面。除此之外，我将尝试描述一些在食物网分析中还不太了解的联系，例如某些群体（例如，吸吮捕食者）的饮食，这代表了食物网中缺失的一环。为了探索这些“缺失的环节”，我将应用NGS技术来分析从肠道内容物分析中看不到的捕食者的饮食，这将使我们能够在食物网结构方面添加有价值的信息。冰岛的站点将作为一个平台，我们将在那里测试方法和实验，然后将其应用于所有其他地热站点。保持这些方法的一致性将是至关重要的，以调查和理清差异和潜在的共性，将出现在不同的网站。特别是，我们预计变暖将在物种差异很大的生态系统中产生类似的模式。最后，我将调查自然系统和中生态系统之间的共性，因为以前的研究已经支持冰岛流和英国中生态系统之间的生态系统呼吸一致的热响应。