Physics-to-Ecosystem Level Assessment of Impacts of Offshore Wind Farms (PELAgIO)

据估计，到2050年，仅北海的海上风能就能收集4亿千瓦的能源。就规模而言，欣克利角C核反应堆预计将产生3.2千兆瓦的电力。人类对沿海海洋利用的增加将如何影响已经面临压力的海洋生态系统？这种可再生能源的生产将如何抵消极端气候变化的风险，如果不加以控制，极端气候变化将增加生物多样性下降的风险。我们现在需要了解与离岸风电场(OWF)相关的生态系统的许多复杂变化，以便以最可持续的方式管理进一步离岸风能开采的程度。大型风能开采的一个重要影响将是减少通常通过表面应力、改变海况和混合而进入当地洋流的能量。相反，涡轮机结构周围的湍流将局部增加，固定基础附近的海床将被冲刷。海洋混合的任何变化都可能在一定程度上改变浮游植物初级生产力的时间、分布和多样性，浮游植物初级生产力是海洋生态系统食物链的基础。这对中上层鱼类的多样性、健康和位置产生了连锁反应，这些鱼类是商业鱼类、海鸟和海洋哺乳动物的关键猎物。观测到的北海南部单翼捕鱼区作业引起的变化包括当地地表温度上升以及海鸟和捕捞船队离开单翼捕鱼区，而海豹似乎常常在涡轮机附近觅食。所有这些变化都有一个相互关联的组成部分，即重要的捕食性鱼类物种，它们很可能聚集在建筑物附近(如其他近海平台所见)。随后，海鸟和捕鱼船队的捕猎空间变得更小，对鱼类的竞争可能会加剧。然而，如果OWF也是事实上的海洋保护区，并因此对当地初级生产产生积极影响，它们可能为鱼类种群增长提供良好的栖息地。那么，目前OWF的发展和数以千计的额外规划建筑的累积影响是什么？物理、生物地球化学和生态系统的变化是否会加剧或缓解气候变化造成的变化？而且，随着OWF作为漂浮结构迁移到更远的近海，如何适当地推断基于浅海沿海固定涡轮机的现有知识，以了解依赖于季节性周期的生态系统的影响，这种季节性周期是典型的深水生态系统的典型特征？PELAGIO将通过一个跨学科的多尺度观察和建模框架解决所有这些问题，该框架跨越物理混合到浮游生物生产，再到鱼类和整个生态系统的反应。我们将使用设置在OWF旁边和远离OWF的最新多仪器声学平台收集精细数据，并辅之以自主水面和海底机器人，以捕获从物理到鱼类的多个尺度和季节的连续和一致数据，以充分了解OWF内部的“不同”以及它的足迹有多大。这些新数据将测试对海鸟和海洋哺乳动物的影响，以建立OWF生态系统参数，该参数说明混合和风力不足影响的变化，并可扩展到下一代OWF。这种自下而上、全面的方法将使从涡轮机基础到区域甚至跨陆架尺度的3D海洋-生物地球化学-沉积物模拟系统能够真正进行校准和验证。已确定的变化将被整合到贝叶斯生态系统模型中，从而能够针对当前条件、极端事件和气候变化定量评估OWF不同政策方法的生态、社会和经济权衡的累积影响。

By 2050 it's estimated >400 GW of energy will be gathered by offshore wind in the North Sea alone. For scale, Hinkley Point C nuclear reactor is projected to produce 3.2 GW. How will this increased anthropogenic use of our coastal seas impact already stressed marine ecosystems? And how will that same production of renewable energy offset risks of extreme climate change that, left unchecked, will increase the risk of biodiversity declines. There are many complex changes to ecosystems linked to Offshore Wind Farms (OWFs) that we need to understand now, so that the extent of increasing wind energy extraction further offshore is managed in the most sustainable way. An important effect of large wind energy extraction will be to reduce the amount of energy that would normally go into local ocean currents via surface stress, altering sea state and mixing. Conversely, there will be local increases in turbulence around turbine structures and seabed scouring near fixed foundations. Any change in ocean mixing may change the timing, distribution and diversity of phytoplankton primary production, the base of the food chain for marine ecosystems, to some degree. This has knock-on-effects on the diversity, health and locations of pelagic fish that are critical prey species of commercial fish, seabirds and marine mammals. Observed changes caused by operational OWFs in the southern North Sea include local surface temperature rise and the displacement of seabirds and fishing fleets from the OWF footprint, whereas seals often appear to be feeding near turbines. All of these changes have a linked component, important prey fish species, which are likely to aggregate near structures (as seen at other offshore platforms). Seabirds and fishing fleets subsequently have less space to hunt, with potentially increased competition for fish. However, if OWFs are also de facto marine protected areas and so positively affect local primary production, they may provide good habitat for fish population growth. So, what are the cumulative effects of current OWF developments and the thousands of additional planned structures? Do the physical, biogeochemical and ecosystem changes exacerbate or mitigate those resulting from climate change? And, as OWFs migrate further offshore as floating structures, how can current knowledge based on shallow, coastal fixed turbines be suitably extrapolated to understand the impacts on ecosystems dependent on seasonal cycles that are typical of deeper waters?PELAgIO will address all of these questions through an inter-disciplinary, multi-scale observation and modelling framework that spans physical mixing through to plankton production, on to the response of fish and whole ecosystems. We will collect fine-scale data using the latest multi-instrumented acoustic platforms set beside and away from OWFs, complemented by autonomous surface and submarine robots to capture continuous and coincident data from physics to fish, over multiple scales and seasons to fully understand what is 'different' inside an OWF and how big its footprint is. These new data will test the effects on seabirds and marine mammals to build an OWF ecosystem parameterization that accounts for changes to mixing and wind deficit impacts, and is scalable to next-generation OWFs. This bottom-up, comprehensive approach will enable true calibration and validation of 3D ocean-biogeochemical-sediment modelling systems, from the scale of turbine foundations up to the regional and even cross-shelf scales. Identified changes will be integrated into Bayesian ecosystem models that enable the cumulative effects of ecological, social and economic trade-offs of different policy approaches for OWFs to be quantifiably assessed for present day conditions, during extreme events and under climate change.