Pathways and Emissions of climate-relevant TRace gases in a changing Arctic Ocean (PETRA)

北冰洋特别容易受到气候变化的影响。最近的研究表明，表层海水变暖的速度比其他海洋快。此外，大气中的二氧化碳在海水中的溶解正在导致海洋酸化。记录在案的海冰消退将增加光的穿透性，包括紫外线。这些环境参数(温度、办公自动化和紫外线)极有可能成为压力源，改变北冰洋生态系统的结构和功能，进而影响气候。一种这样的反馈是气候活跃的痕量气体的循环及其向大气的排放(这里：CH4、N2O、DMS、CO)。这些微量气体通过一些物理和生物过程迅速产生和消耗。例如，表层海水中CO的最大来源是紫外线诱导的光化学反应。然而，微量气体循环对气候变化的可能反应在很大程度上仍未得到探索。这阻碍了我们预测这一重要气候反馈未来方向的能力。我们建议通过a)建立支持预测工具的基本理解和b)开发预测工具本身(计算机模型)来研究这种反馈。我们将使用三种免费工具来实现这一点：第一，对痕量气体进行新颖、高科技的空间观测(深度和水平)，这将使我们能够确定其循环的主要控制因素，并估计它们目前进入大气的通量。其次，直接实验，在监控微量气体循环路径的同时，操纵这三个应激源。这里我们方法的新奇之处在于使用了单独的和组合的应激源处理(例如，单独的OA与高温和一起的OA)。这将使我们能够探索应激源之间潜在的协同或拮抗效应。我们将使用最先进的化学和生物观察来跟踪微量气体循环的变化。例如，我们将监测参与微量气体循环的关键基因的丰度和活性。这些实验将使我们清楚而精细地了解微量气体循环与应激源的关系。第三，我们将使用计算机建模，将这种理解转化为预测工具，用于预测未来气候变化的影响。最后，为了迅速将我们的相关发现转化为政策，我们将通过我们的全面影响计划与公众、政策制定者、国际科学方案和政府间气候变化专门委员会(气专委)接触。

The Arctic Ocean is exceptionally susceptible to climate change. Recent studies have shown that surface seawater is warming faster than in other oceans. In addition, atmospheric CO2 dissolution in seawater is causing Ocean Acidification (OA). The documented retreat of sea-ice will increase light penetration, including UV. These environmental parameters (temperature, OA and UV) are highly likely to act as stressors and alter the Arctic Ocean ecosystem structure and function which in turn will feed back on climate. One such feedback is the cycling of climatically active trace gases and their emission to the atmosphere (here: CH4, N2O, DMS, CO). These trace gases are rapidly produced and consumed by a number of physical and biological processes. For example, the biggest source of CO in surface seawater is via UV-induced photochemical reactions. Yet, the likely response of trace gas cycling to climate change remains largely unexplored. This hinders our ability to predict the future direction of this important climate-feedback. We propose to investigate this feedback by a) developing the basic understanding which will underpin a predictive tool and b) developing the predictive tool itself (computer model). We will achieve this using three complimentary tools: Firstly, novel, high-tech spatial observations of trace gases (with depth as well as horizontal) which will allow us to identify major controls on their cycles and estimate their present flux to the atmosphere. Secondly, direct experiments where the three stressors will be manipulated while trace gas cycling pathways are monitored. The novelty of our approach here, lies in the use of individual and combined stressor manipulation (e.g. OA alone versus high temperature and OA together). This will allow us to explore potential synergistic or antagonistic effects between stressors. We will use state-of-the-art chemical and biological observations to track changes in trace gas cycling. For example, we will monitor the abundance and activity of key genes involved in trace gas cycling. These experiments will give us explicit and refined understanding of trace gas cycling in relation to the stressors. Thirdly, we will employ computer modelling which will translate this understanding into a predictive tool that will be used to predict the impact of future climate change. Finally, and in order to rapidly translate our relevant findings to policy, we will engage with the public, policymakers, international science programmes and Intergovernmental Panel on Climate Change (IPCC) through our comprehensive impact plan.