Biogeochemistry, macronutrient and carbon cycling in the benthic layer

在我们整个历史上，我们周围的海岸和陆架海一直是人类繁荣和福祉的焦点，因此对我们的文化产生了不成比例的影响。陆架海的社会重要性不仅限于粮食生产，还包括生物多样性、碳循环和储存、废物处理、营养循环、娱乐和可再生能源。然而，随着越来越多的全球人口向海岸靠拢，我们的海洋已逐渐受到人类活动的侵蚀，包括过度捕捞、污染、栖息地干扰和气候变化。这令人担忧，因为海底状况、生物多样性和人类社会密不可分。因此，迫切需要了解一系列大陆架栖息地的相对敏感性，以便更有效地管理人类压力，以确保我们海洋的长期可持续性和提供社会效益。实现这些目标并不是一帆风顺的，因为海底提供我们所依赖的货物和服务的能力取决于底物的类型(岩石、砾石、沙、泥)和当地条件；一些栖息地是自然动态的，对干扰相对不敏感，而另一些生境相对稳定，容易发生变化。这使得我们很难评估栖息地的敏感性，也很难就我们未来可以从我们的海洋中获得什么好处发表一般性的声明。最近，NERC和DEFRA启动了一项关于大陆架海洋生物地球化学的重大新研究计划，将增进对这些问题的了解。为响应这一号召，我们召集了一个由顶尖科学家组成的联盟，其中包括微生物学家、生态学家、物理海洋学家、生物地球化学家、数学模型师和政策顾问。在CEFAS、海洋苏格兰和美国联邦调查局等组织的帮助下，他们将在英国各地开展一系列研究巡航，根据海底栖息地的物理条件、栖息地的微生物和动物群落，以及那里发现的氮库和碳库的大小和动态，绘制海底栖息地的敏感性和状况图。最新的海洋技术将测量海床上方的混合量和流速，以及详细的海底地形。这些测量将使人们能够更好地了解导致沉积物、营养物质和碳的移动和混合的物理过程。同时，将取回含有微生物和动物群的岩心，它们的活动和行为将与特定的生物地球化学反应联系在一起。被称为着陆器的高度专业化的自动车辆也将测量海底的营养物质浓度和通量。然后，可以对该系统的组件进行试验性操作，以模拟变化的情景，例如变化的水动力、干扰或气候变化的组成部分。这将在现场通过使用淹没的水槽产生不同的流动状态来实现，或者在实验室使用暴露在不同水平的二氧化碳、温度和氧气中的完整沉积物群落来实现。通过测量微生物和动物群落对这些变化的生物地球化学反应和行为，我们将了解如果这些变化确实发生在我们的陆架海可能会发生什么。我们将使用所有这些信息，通过将观测和实验结果叠加到各种人类压力的地图上，来评估英国海床区域的相对脆弱性，这将对规划者和政策制定者有价值。数学模型将测试未来变化的情景，例如开放或关闭脆弱区域捕鱼，或控制营养和碳储备的因素预期的变化。这将有助于探讨对外部压力的不同反应，并决定应采取哪些管理措施，为子孙后代保护我们的大陆架海洋。

The coasts and shelf seas that surround us have been the focal point of human prosperity and well-being throughout our history and, consequently, have had a disproportionate effect on our culture. The societal importance of the shelf seas extends beyond food production to include biodiversity, carbon cycling and storage, waste disposal, nutrient cycling, recreation and renewable energy. Yet, as increasing proportions of the global population move closer to the coast, our seas have become progressively eroded by human activities, including overfishing, pollution, habitat disturbance and climate change. This is worrying because the condition of the seabed, biodiversity and human society are inextricably linked. Hence, there is an urgent need to understand the relative sensitivities of a range of shelf habitats so that human pressures can be managed more effectively to ensure the long-term sustainability of our seas and provision of societal benefits. Achieving these aims is not straightforward, as the capacity of the seabed to provide the goods and services we rely upon depends on the type of substrate (rock, gravel, sand, mud) and local conditions; some habitats are naturally dynamic and relatively insensitive to disturbance, while others are comparatively stable and vulnerable to change. This makes it very difficult to assess habitat sensitivities or make general statements about what benefits we can expect from our seas in the future.Recently, NERC and DEFRA have initiated a major new research programme on Shelf Sea Biogeochemistry that will improve knowledge about these issues. In response to this call, we have assembled a consortium of leading scientists that includes microbiologists, ecologists, physical oceanographers, biogeochemists, mathematical modellers and policy advisors. With assistance from organisations like CEFAS, Marine Scotland and AFBI, they will carry out a series of research cruises around the UK that will map the sensitivity and status of seabed habitats based on their physical condition, the microbial and faunal communities that inhabit them, and the size and dynamics of the nitrogen and carbon pools found there. The latest marine technologies will measure the amount of mixing and flow rates just above the seabed, as well as detailed seabed topography. These measurements will allow better understanding of the physical processes responsible for movement and mixing of sediment, nutrient, and carbon. At the same time, cores will be retrieved containing the microbial and faunal communities and their activity and behaviour will be linked to specific biogeochemical responses. Highly specialised autonomous vehicles, called landers, will also measure nutrient concentrations and fluxes at the seabed. Components of the system can then be experimentally manipulated to mimic scenarios of change, such as changing hydrodynamics, disturbance or components of climate change. This will be achieved in the field by generating different flow regimes using a submerged flume or, in the laboratory, using intact sediment communities exposed to different levels of CO2, temperature and oxygen. By measuring the biogeochemical response and behaviour of the microbial and faunal communities to these changes, we will generate an understanding of what may happen if such changes did occur across our shelf seas.We will use all of this information to assess the relative vulnerability of areas of the UK seabed by overlaying the observation and experimental results over maps of various human pressures, which will be of value to planners and policymakers. Mathematical models will test future scenarios of change, such as opening or closing vulnerable areas to fishing or anticipated changes in the factors that control nutrient and carbon stocks. This will be valuable in exploring different responses to external pressures and for deciding which management measures should be put in place to preserve our shelf seas for future generations.