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

混沌将量化海冰覆盖变化对有机质质量、海底生物多样性、碳库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质(OM)和相关营养物质的数量、来源和生物可利用性；确定其在海底食物链中的消耗、转化和循环；以及最终将其埋藏或循环回到水柱，从而实现这一目标。我们将结合(1)对横跨冰缘的典型北极陆架海洋生境的详细研究，(2)大规模现场验证研究和船上实验，(3)将查明因果关系和机制的操纵性实验室实验，(4)分析加拿大、挪威和德国北极方案获得的高度空间和时间分辨率的数据，以确定一般性，(5)将对生物多样性、生物地球化学途径和营养循环的控制和影响的新理解纳入模拟办法，以探讨北极海冰的变化如何改变区域规模的生态系统，从而研究这些耦合的生物和生物地球化学过程。我们将重点关注海冰覆盖急剧变化是主要环境控制因素的北冰洋部分地区，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。虽然我们首选的震源区是沿巴伦支海东经30度的北S断面，那里的冰的扩张和消退是众所周知的，并且可以安全地进入，但我们也将使用额外的邮轮前往与挪威有类似沉积物和水条件的地点，为考虑未来环境强迫的扩展实验室实验取回关键物种。重要的是，我们活动的设计不是针对特定地点的，允许我们的方法应用于具有相似区域特征的其他地区。这种灵活性最大限度地扩大了所有方案联合体(远洋或海底)之间协调活动的范围，前提是一旦对机会宣布的所有答复都得到评估，北极大陆架的其他区域就更可取。为支持我们的实地活动，并根据我们的国际合作伙伴(挪威、加拿大、美国、意大利、波兰和德国)获得的实地样本和数据的分析，我们将进行一系列严格限制的实验室实验，使孵化的自然沉积物暴露在最有可能随海冰覆盖变化而变化的环境条件下，并分析生物和生物地球化学对这些引起的当前和未来环境变化(例如海洋酸化、变暖)的反应。我们将利用国际项目伙伴提供的现有补充数据集，实现对北冰洋不同部分的更广泛的时空覆盖。英国八家领先研究机构的专业知识(微生物学家、地球化学家、生态学家、模型师)和设施的独特结合，将使我们能够在作为海底生态系统食物来源的出口有机质的数量和质量、整个海底生物的生物多样性和生态系统功能的响应以及对回收池和埋藏池之间碳和养分分配的影响之间建立新的联系。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)和横跨陆地-海洋过渡的生物地球化学过程的补充项目建立密切联系。这将提供综合的数据集和过程理解，以及开发预测模型(例如美杜莎)所需的新颖的、在数值上有效的提升工具，以便将海底的数量纳入对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.