Ecosystem functions controlled by sea ice and light in a changing Arctic (Eco-Light)

北极变暖的速度是地球上任何其他地区的两倍多。这种变暖导致了整个北极地区的可量化变化;陆地，海洋和大气。然而，最引人注目的变化可能与北极海冰有关。例如，卫星记录显示，所有月份的海冰面积都大幅减少，特别是在夏季。夏季海冰面积从1970年代末的约700万平方公里减少到2012年的约340万平方公里，减少了50%以上。对海底记录的时间序列分析得出结论，平均厚度下降了40%以上，这些变化共同导致了北极冰态的根本转变。北极不再是一个由厚的多年冰（MYI）主导的地区，而是一个由更薄，更动态的第一年冰（FYI）控制的地区。事实上，复杂的计算机模型预测，北冰洋将在未来几十年内（如果不是更早的话）在夏季变得基本无冰。我们对北极海洋生态系统功能的理解绝大多数来自MYI设置，而不是近年来由FYI主导的北极。因此，我们目前对这些过程的了解以及目前嵌入计算机模型中的许多参数化的有效性变得更加值得怀疑。例如，最近的研究表明，从MYI到FYI夏季冰盖的过渡对应于上层海洋透光率增加200%。光是控制海冰下初级生产的关键因素之一，此外，最近的建模研究表明，海冰藻华是由光照引发的。因此，如果我们要理解和预测这个“新北极”的生态系统功能，我们必须理解和正确地参数化我们今天和可预见的未来所处的新FYI环境下的光气候。为了正确地做到这一点，我们需要一种整体的方法，无缝地将生物学，光学，海冰和海洋物理学，以及卫星遥感和尖端建模结合起来。这个名为“生态之光”的方案利用联合王国和德国的建模和观测专门知识，更好地了解北极海冰变化对生态系统功能的影响。这是通过在观测上限制和改善这个“新”北极的光传输过程的参数化来实现的，通过这样做，我们将更好地了解它对生态系统功能的影响。这些信息将用于解决真光深度的初级生产力，并预测不断变化的雪冰海洋成分对水下光climate.Eco-Light无疑将产生强大的遗产，英国和德国在北极观测科学，生态系统动力学和预测建模的关键方面的领导地位。

SUMMARYThe Arctic is warming more than twice as fast as any other region of our planet. This warming has led to quantifiable changes right across the Arctic; land, ocean and atmosphere. However, the most dramatic changes are possibly those associated with Arctic sea ice. For example satellite records have revealed a significant decrease in sea ice extent in all months, especially in summer. There has been a reduction in summer sea ice extent from about 7 million square kilometres in the late 1970s to around 3.4 million square kilometres in 2012; a reduction of over 50%. Time-series analysis of submarine records concluded that the mean thickness has declined by more than 40%, and taken together that these changes have led to a fundamental shift in the ice regime in the Arctic. The Arctic is no longer a region dominated by a thick multi-year ice (MYI), but it is a regime controlled by thinner, more dynamic, first year ice (FYI). In fact complex computer models predict that the Arctic Ocean is on track to become mostly ice free in summer within a few decades, if not earlier.Our understanding of the functioning of the Arctic marine ecosystem has been overwhelmingly derived from a MYI setting, rather than the FYI dominated Arctic of recent years. As a result, our current state of knowledge of these processes and the validity of many of the parameterisations presently embedded in computer models becomes more questionable. For example, recent studies revealed that that the transition from MYI to FYI summer ice cover corresponds to an increase of 200% in light transmittance into the upper ocean. Light is one of the critical ingredients that controls primary production under sea ice, and in addition recent modelling studies have shown that the sea-ice algal blooms are triggered by light availability. Therefore if we are to understand and predict ecosystem function in this 'new Arctic', we must understand and correctly parameterise the light climate under this new FYI environment we find ourselves in today, and for the foreseeable future. To do this correctly we need a holistic approach that seamlessly brings biology, optics, sea ice and ocean physics, together with satellite remote sensing and cutting-edge modelling. This programme, Eco-Light, does this by utilising the modelling and observational expertise of the United Kingdom and Germany to better understand the influence of changing Arctic sea ice on ecosystem function. This is achieved by observationally constraining and improving the parameterisations of processes of light transmission in this 'new' Arctic, and by doing so we will better understand its influence on ecosystem function. This information will be used to resolve euphotic depths for primary productivity, and to predict the effects of changing snow-ice-ocean constituents on the underwater light climate.Eco-Light will undoubtedly produce a strong legacy for UK and Germany leadership in key aspects of Arctic observational science, ecosystem dynamics, and predictive modelling.