Sclerochronology and modelling: combining annually resolved bivalve records and biogeochemical models to understand the shelf seas

我们的沿海海洋是捕鱼、污染和气候变化的许多影响所在的地方，而且将越来越多地感受到这种影响。例如，世界银行估计，到2050年，仅气候对旅游业和渔业的影响就将给全球经济造成950亿至1470亿美元的损失。沿海水域的脆弱性现已得到广泛认识，为此正在推出创新和广泛的监测系统。然而，我们缺乏将最近观察到的变化放在背景中所需的过去观察--它是由人类还是自然造成的？我们也缺乏对长期(几十年)变化的观测，这对于校准用于展望未来和探索沿海海洋可能如何响应不同管理策略的模型是必要的。因此，在这个项目中，我们将把观测记录延长到过去，并以一种我们可以利用并仔细测试海岸洋流和生态系统模型的方式来进行这项工作。我们过去的记录将来自从北海海底和英格兰、威尔士和苏格兰西海岸收集的蛤壳。这些蛤壳(或双壳类)活了几十年到几百年。我们研究的样本包括迄今发现的最长寿的动物--超过500岁。每年，双壳贝类都会长出一条新的贝壳材料带--就像树轮一样。研究人员发现，在不同的位置，这些带的宽度变化记录了环境变化的不同方面，可能是通过不断变化的食物供应。到目前为止，还没有人把来自不同地点的所有信息放在一起，得出控制双壳类生长的整体因素的单一描述--因此，没有人充分发挥它们的潜力来重建过去环境的变化。这是以前没有做过的，因为对潜在重要因素(浮游生物浓度、营养物质浓度等)的观察。我们将使用过去50年来最先进的沿海海洋的3D模型模拟，通过同化(吸收)海洋和/或大气观测来重建不断变化的海洋和生态系统状态。通过仔细识别这些模型在哪里以及在哪些方面做得很好，我们可以用模型中的信息来补充观察，并确定最终导致双壳类生长变化的原因。利用对环境变化和双壳类生长变化之间联系的新理解，我们可以解释长期(数十年到数百年)的双壳类生长记录，并重建我们的沿海水域过去是如何变化的。我们还可以将这种理解建立在模型中，使我们能够预测双壳类的生长在未来可能会发生什么变化。这个项目需要埃克塞特大学和班戈大学与洛斯托夫特的环境、水产养殖和渔业中心(CEFA)之间的三方合作。埃克塞特大学是气候变化研究的先锋，拥有从气候到生态系统建模以及从社会经济影响到适应的专业知识。班戈大学开创了双壳类动物重建技术的先河，其中包括研究“地球上最长寿的动物”。CEFA是公认的海洋生物科学领导者，政府的职责是确保健康和可持续的海洋环境。CEFA运行着英国的海洋模型，该模型最全面地模拟了海底的生物和化学过程，并将利用我们的发现来帮助履行英国的海洋环境承诺。通过将这些专业知识和对气候、过去的环境重建和海洋生态系统的理解结合在一起，我们希望提供最好的工具来处理关于人类活动对我们沿海海洋的过去、现在和未来影响的新问题。

Our coastal oceans are where many of the impacts of fishing, pollution and climate change are being, and will increasingly be felt. For example, by 2050, the World Bank estimates that climate impacts on tourism and fisheries alone will cost the global economy between 95 and 147 billion USD.The vulnerability of coastal waters is now widely recognised, and in response innovative and extensive monitoring systems are being rolled out. However, we lack the past observations required to place recently observed change in context - is it caused by humans or nature? We also lack observations of long-term (decades) change, necessary for calibrating models used to look into the future and explore how coastal oceans may respond to different management strategies.In this project, we will therefore extend the observational records back in time, and do this in such a way that we can make use of, and carefully test, models of coastal currents and ecosystems. Our past records will come from clam shells collected from the bottom of the North Sea and off the West coasts of England, Wales and Scotland.These clams (or bivalves) live for many decades to hundreds of years. Samples we have worked on include the longest-lived animal ever found - over 500 years old. Each year bivalves grow a new band of shell material - much like a tree ring. Researchers have found that at different locations, the changing width of these bands records different aspects of how the environment has changed, probably mediated through a changing food supply.So far no one has put all of the information from different locations together to come up with a single description of the overall factors controlling bivalve growth - and consequently no one has fully opened up their potential to reconstruct past changes in the environment. This has not previously been done because observations of the potentially important factors (plankton concentrations, nutrient concentrations etc.) are limited to a small number of sites, often far from where the bivalves have been collected.We will use state-of-the-art 3D model simulations of the coastal ocean spanning the last 50 years, which reconstruct the changing ocean and ecosystem state by assimilating (taking in) ocean and/or atmospheric observations. By carefully identifying where and in what respects these models are doing a good job, we can supplement observations with information from the models, and identify what is ultimately causing the bivalve growth to vary.Using this new understanding of the link between environmental change and bivalve growth change, we can interpret long (many decades to centuries) bivalve growth records, and reconstruct how our coastal waters have changes in the past. We can also build this understanding into models to allow us to predict how bivalve growth may change in the future.This project requires a 3-way collaboration between the Universities of Exeter and Bangor and the Centre for the Environment, Aquiculture and Fisheries (Cefas) in Lowestoft. The University of Exeter is at the vanguard of climate change research, with expertise from climate to ecosystem modeling, and socioeconomic impacts to adaptation. Bangor University pioneers bivalve reconstruction techniques, including working with the 'longest-lived animal on Earth'. Cefas are recognised leaders in marine biological science, with a government remit to secure healthy and sustainable marine environments. Cefas run the UK's ocean model which most comprehensively simulates the biological and chemical processes on the sea-floor, and will make use of our findings to help meet the UK's marine environmental commitments.By bringing together this expertise and understanding in climate, past environmental reconstruction and marine ecosystems, we hope to deliver the best possible tools for tacking emerging questions about the past, present and future impact of human activity on our coastal oceans.