Changing Arctic Carbon cycle in the cOastal Ocean Near-shore (CACOON)

全球气候变化导致全球气温大幅上升，特别是在北极地区。这导致了降雨和积雪模式的变化，以及陆地系统的结构和稳定性。与热带地区不同的是，陆地上的大部分碳通常储存在陆地上的树木中，而北极地区则有大量被锁在地下的冻土和冰中的碳，也就是所谓的永冻土。这块永久冻土层已经被锁了几万年，仍然经常含有猛犸象和外来病毒的残骸[1]。北冰洋(AO)从北极大陆接收大量物质，其中大部分由巨大的北冰洋河流输送，这些河流排干了欧亚和美洲北极的大片地区。这些河流现在正在从陆地向海洋输送更多的水，这是由气候驱动的降雨量增加和永久冻土融化所推动的。这将导致从陆地向海洋输送的材料的数量、年龄和类型发生变化。那么，为什么这很重要呢？通过海洋植物吸收二氧化碳，并随后将其中的一小部分输出到深海--将碳从大气中锁住--AO在碳的储存和循环中发挥着至关重要的作用。海洋也是细菌(和其他过程)的宿主，细菌可以将碳从海洋释放到大气中。这些过程的平衡对于决定AO未来将储存或释放多少碳至关重要。目前，我们认为北极涛动是一年中二氧化碳的一个小“储存库”，但这种情况在未来可能会改变，对全球气温造成危险的后果。我们将研究这些过程，重点放在淡水与海洋交汇的沿海地区。到目前为止，研究只集中在河流或海洋本身，但很少有人研究它们在哪里汇合。我们建议进行三种不同的研究，以填补我们知识中的这些空白。我们将研究东西伯利亚陆架海(ESAS)地区，以及两个非常大的北冰洋河流水系(Kolyma河和Lena河)，它们通过这个陆架流入AO。我们将重点关注这一偏远的俄罗斯北极地区，因为它目前正在经历极其迅速的气候变暖，这里的河流径流量正在迅速增加，尽管大陆架覆盖了非常大的面积，但人们对这一地区将如何变化知之甚少。首先，我们将在两个研究地点进行实地采集水的活动，在冬季、夏季和春季对水、土壤和沉积物进行采样。这将包括在夏天乘船采样，以及在西伯利亚冬季在冰上钻探。其次，我们将从野外带回样本，进行详细的实验，以确定关键的环境过程，如阳光和细菌，如何在陆地物质从河流进入AO时使用和改变它们。这包括向水中照射人造阳光，看看材料是如何变化的，或者让微生物‘吃’水中的东西，看看他们使用了什么，以及使用的速度有多快。最后，我们将结合我们的发现来开发建模工具，使我们能够对ESAS上的水和材料从陆地到海洋的流动进行建模或‘模拟’。这个模型将包含不同的隔间，代表来自陆地的材料的不同部分，例如不同的营养物质或碳类型。此外，它还将模拟生态系统中的主要(从小到微观)生物群体，例如细菌和不同的浮游植物群体。这将使我们能够研究AO及其生物过程将如何应对未来淡水供应的变化和永冻层的增加，并最终确定这些过程可能如何改变AO在全球气候中的作用。[1]http://www.bbc.com/earth/story/20170504-there-are-diseases-hidden-in-ice-and-they-are-waking-up

Global climate change has led to substantial increases in air temperatures across the Earth, particularly in Arctic regions. This has led to changes in patterns of rainfall and snow cover, as well as the structure and stability of terrestrial systems. Unlike the tropics - where the majority of land-based carbon is usually stored in trees on land, the Arctic plays host to vast quantities of carbon locked up underground in frozen soils and ice, known as permafrost. This permafrost has been locked up for tens of thousands of years, and still often contains the remains of woolly mammoth, and exotic viruses [1]. The Arctic Ocean (AO) receives huge quantities of material from the Arctic mainland, much being delivered by giant Arctic rivers that drain vast swathes of the Eurasian and American Arctic. These rivers are now delivering greater quantities of water from land to the ocean, fuelled by climate-driven increases in rainfall and permafrost thaw. This will cause a shift in the amount, age and type of materials being delivered from land to the ocean. So, should why is this important? The AO plays a crucial role in the storage and cycling of carbon, through the uptake of CO2 by marine plants, and the subsequent export of a fraction of this to the deep ocean - locking away carbon from the atmosphere. The ocean also plays host to bacteria (and other processes), which can release carbon from the ocean to the atmosphere. The balance of these processes is critical in determining how much carbon the AO will store, or release, in the future. Currently, we think the AO is a small overall 'store' of CO2 over the year, but this could change in the future, with hazardous consequences for global temperatures. We will examine these processes, focusing upon coastal regions where freshwaters meet the ocean. Studies to date, have focused upon rivers only, or the ocean itself, but few have investigated where they mix. We propose to carry out three different strands of research that will fill these gaps in our knowledge. We will study the East Siberian Shelf Sea (ESAS) region, and two very large Arctic river systems (the Kolyma and Lena Rivers) that drain into the AO over this shelf. We'll focus on this remote Russian Arctic area as it is currently experiencing extremely rapid climate warming, riverine runoff rates are increasing fast here, and despite the shelf covering a very large area little is known about how this region will change. Firstly, we'll conduct field campaigns collecting waters across the two study sites, sampling waters, soils and sediments during winter, summer and spring. This will involve sampling by boat in summer, and by skidoo - with drilling over ice during the Siberian winter. Secondly, we'll bring samples back from the field to conduct detailed experiments to determine how key environmental processes, such as sunlight and bacteria, use and alter terrestrial materials as they move from the rivers into the AO. This includes shining artificial sunlight at waters to see how materials change, or allowing microbes to 'feed' on what's in the water to see what they use and how quickly. Lastly, we'll combine our findings to develop modelling tools allowing us to model, or 'simulate', how fluxes of water, and materials travel from land-to-ocean over the ESAS. This model will contain separate compartments, representing different fractions of the materials sourced from land, for example different nutrients or carbon types. Also, it will simulate the major (small to microscopic) biological groups within the ecosystem, for example bacteria, and different phytoplankton groups. This will allow us to examine how the AO, and its biological processes will respond to future changes in freshwater supply and increased permafrost, and ultimately identify how these processes may alter the role of the AO in global climate.[1] http://www.bbc.com/earth/story/20170504-there-are-diseases-hidden-in-ice-and-they-are-waking-up