The Changing Arctic Ocean Seafloor (ChAOS) - how changing sea ice conditions impact biological communities, biogeochemical processes and ecosystems

ChAOS将量化海冰覆盖变化对有机物质量、底栖生物多样性、碳和营养库的生物转化以及由此产生的北冰洋海底生态系统功能的影响。我们将通过确定输出到北极海底的有机物（OM）和相关营养物质的数量，来源和生物利用度来实现这一目标;它的消费，转化和通过底栖食物链的循环;以及它最终的埋葬或回收到水柱中。我们将研究这些耦合的生物和地球化学过程相结合（一）一个详细的研究代表北极陆架海栖息地，相交的冰边缘，与（二）大规模的原位验证研究和船上实验，（三）操纵实验室实验，将确定因果关系和机制，（四）分析的高度空间和时间分辨的数据获得的加拿大，挪威和德国的北极计划，以建立普遍性，以及（五）我们将纳入新的理解控制和生物多样性，生物地球化学途径和营养循环的影响建模方法，探讨如何在北极海冰的变化改变生态系统在区域范围内。我们将重点关注北冰洋的部分地区，海冰覆盖的剧烈变化是主要的环境控制因素，例如，巴伦支海共同的实地考察活动将构成我们研究活动的核心。尽管我们首选的重点区域是巴伦支海东部沿着30度的南北横断面，那里的冰扩张和退缩是众所周知的，并且可以安全到达，但我们还将使用额外的巡航前往挪威具有相似沉积物和水条件的地点，检索关键物种以进行考虑未来环境强迫的扩展实验室实验。重要的是，我们运动的设计不针对具体地点，使我们的方法能够应用于具有类似区域特点的其他地区。一旦对《机会公告》作出的所有反应进行了评价，如果北极大陆架的其他区域更可取，这种灵活性就能最大限度地扩大所有方案联营体（中上层或海底）之间协调活动的范围。支持我们的实地活动，并通过对国际合作伙伴获得的实地样品和数据的分析提供信息（挪威、加拿大、美国、意大利、波兰和德国），我们将进行一系列严格限制的实验室实验，将培养的天然沉积物暴露于最有可能随海冰覆盖面积变化而变化的环境条件下，并分析生物学和地球化学对这些在当前与未来环境中引起的变化的响应（例如，海洋酸化、变暖）。我们将利用国际项目伙伴提供的现有补充数据集，扩大北冰洋不同部分的时空覆盖范围。专业知识的独特组合（微生物学家，地球化学家，生态学家，建模师）和八个英国领先研究机构的设施将使我们能够在作为底栖生态系统食物来源的出口OM的数量和质量之间建立新的联系，生物多样性的反应和底栖生物全谱生态系统功能，以及对碳和养分在循环池和埋藏池之间分配的影响。为了将底栖亚系统与整个北冰洋联系起来，我们将与研究水柱、底栖环境（及其相互作用）和陆地-海洋过渡中的生物地球化学过程的补充项目建立密切联系。这将提供开发预测模型所需的组合数据集和过程理解，以及新颖的、数值上有效的升级工具（例如，MEDUSA），允许将海底定量纳入不断变化的北冰洋的环境预测。

ChAOS will quantify the effect of changing sea ice cover on organic matter quality, benthic biodiversity, biological transformations of carbon and nutrient pools, and resulting ecosystem function at the Arctic Ocean seafloor. We will achieve this by determining the amount, source, and bioavailability of organic matter (OM) and associated nutrients exported to the Arctic seafloor; its consumption, transformation, and cycling through the benthic food chain; and its eventual burial or recycling back into the water column. We will study these coupled biological and biogeochemical processes by combining (i) a detailed study of representative Arctic shelf sea habitats that intersect the ice edge, with (ii) broad-scale in situ validation studies and shipboard experiments, (iii) manipulative laboratory experiments that will identify causal relationships and mechanisms, (iv) analyses of highly spatially and temporally resolved data obtained by the Canadian, Norwegian and German Arctic programmes to establish generality, and (v) we will integrate new understanding of controls and effects on biodiversity, biogeochemical pathways and nutrient cycles into modelling approaches to explore how changes in Arctic sea ice alter ecosystems at regional scales. We will focus on parts of the Arctic Ocean where drastic changes in sea ice cover are the main environmental control, e.g., the Barents Sea. Common fieldwork campaigns will form the core of our research activity. Although our preferred focal region is a N-S transect along 30 degree East in the Barents Sea where ice expansion and retreat are well known and safely accessible, we will also use additional cruises to locations that share similar sediment and water conditions in Norway, retrieving key species for extended laboratory experiments that consider future environmental forcing. Importantly, the design of our campaign is not site specific, allowing our approach to be applied in other areas that share similar regional characteristics. This flexibility maximizes the scope for coordinated activities between all programme consortia (pelagic or benthic) should other areas of the Arctic shelf be preferable once all responses to the Announcement of Opportunity have been evaluated. In support of our field campaign, and informed by the analysis of field samples and data obtained by our international partners (in Norway, Canada, USA, Italy, Poland and Germany), we will conduct a range of well-constrained laboratory experiments, exposing incubated natural sediment to environmental conditions that are most likely to vary in response to the changing sea ice cover, and analysing the response of biology and biogeochemistry to these induced changes in present versus future environments (e.g., ocean acidification, warming). We will use existing complementary data sets provided by international project partners to achieve a wider spatial and temporal coverage of different parts of the Arctic Ocean. The unique combination of expertise (microbiologists, geochemists, ecologists, modellers) and facilities across eight leading UK research institutions will allow us to make new links between the quantity and quality of exported OM as a food source for benthic ecosystems, the response of the biodiversity and ecosystem functioning across the full spectrum of benthic organisms, and the effects on the partitioning of carbon and nutrients between recycled and buried pools. To link the benthic sub-system to the Arctic Ocean as a whole, we will establish close links with complementary projects studying biogeochemical processes in the water column, benthic environment (and their interactions) and across the land-ocean transition. This will provide the combined data sets and process understanding, as well as novel, numerically efficient upscaling tools, required to develop predictive models (e.g., MEDUSA) that allow for a quantitative inclusion seafloor into environmental predictions of the changing Arctic Ocean.