Collaborative Research: The effect of carbonate chemistry on the sea ice community in the High Arctic

海冰影响着北极发生的许多物理、大气、化学和生物过程。海冰也是一个具有挑战性的栖息地评估：它随风移动，因此几乎总是独立于地表水移动。冰的特性影响着大气、冰和海洋表面之间的一系列化学和生物相互作用，这些特性随着时间和空间的变化而变化。虽然预计在日益无冰的北冰洋中，光合作用会增强，但很少有研究确定大气中二氧化碳（CO2）的增加和其他环境变化对生长在海冰内和海冰下的微生物的影响。这项研究将有助于我们了解北极中部盆地的元素循环，以及海冰生物群落在快速变化的环境下的脆弱性，特别是在二氧化碳浓度增加和海洋酸化的影响下。该项目是美国和瑞典联合合作的一部分，将支持一名早期职业女性教员。它还将支持培训一名研究生和一名博士后科学家，他们将获得正在进行和离散的生物地球化学采样以及孵化实验的经验。调查人员将在西雅图太平洋科学中心举行的VIMS海洋科学日和极地科学周末上开展有关北冰洋变化的公众宣传活动。这项研究的总体目标是评估大气中二氧化碳（CO2）增加导致的海水化学变化将如何改变海冰中藻类-细菌的相互作用。最近北极海冰的减少导致大气中二氧化碳的吸收增加，加速了这个正在迅速变化的地区的酸化速度。虽然在日益无冰的北极地区，海洋生产力有望提高，但环境变化对依赖冰的生物群落的影响很难预测。作为美国和瑞典联合合作的一部分，这项工作将对依赖冰的藻类和细菌对pH值变化的敏感性进行定量评估，并利用正在进行的和离散采样的结合，在夏末海冰最小的时候，对北极高纬度地区二氧化碳系统的时空变化进行新的观测。此外，研究小组将进行一套船上实验，操纵海水pH值，以评估对海冰生物群及其外聚合物多糖产物的影响。虽然以前的工作主要集中在二氧化碳升高对浮游植物的影响上，但对依赖冰的生物群的针对性研究很少。考虑到北极中部盆地CO2系统观测的缺乏，特别是在生产季节后期，秋季生产和季节性最低盐度的影响可以包括在累积产量估计中，因此这里提出的观测将具有特别重要的意义。

Sea ice influences many physical, atmospheric, chemical and biological processes occurring in the Arctic. Sea ice is also a challenging habitat to assess: it moves in response to wind, and hence nearly always moves independently of surface waters. The properties of the ice, which influence a suite of chemical and biological interactions between the atmosphere, the ice, and the surface ocean, change over both space and time. While enhanced photosynthesis is expected in the increasingly ice-free Arctic Ocean, there has been little research to determine the impact of increased atmospheric carbon dioxide (CO2) and other environmental changes on the microbes that grow within and beneath the sea ice. This research will contribute to our understanding of elemental cycles in the central Arctic basin and of the vulnerability of the sea ice biological community to a rapidly changing environment, particularly as it is impacted by increasing carbon dioxide concentrations and ocean acidification. The project is part of a joint US-Swedish collaboration and will support an early-career female faculty member. It will also support the training of a graduate student and a postdoctoral scientist who will gain experience with underway and discrete biogeochemical sampling as well as incubation experiments. The investigators will conduct public outreach about changes in the Arctic Ocean at the VIMS Marine Science Day and Polar Science Weekend at the Pacific Science Center in Seattle. The overall objective of this research is to assess how changes in seawater chemistry as a result of increases in atmospheric carbon dioxide (CO2) will alter algal-bacterial interactions in sea ice. Recent losses of Arctic sea ice have resulted in an increased uptake of atmospheric CO2, accelerating the rate of acidification in a region that is rapidly changing. While enhanced marine productivity is expected in an increasingly ice-free Arctic, the impact of the changing environment on ice-dependent biological communities is challenging to predict. As part of a joint US-Swedish collaboration, this work will provide a quantitative assessment of the sensitivity of ice-dependent algae and bacteria to changes in pH and use a combination of underway and discrete sampling to deliver new observations on the spatial and temporal variability of the CO2 system in the High Arctic in late summer when sea ice is at a minimum. In addition, the research team will perform a suite of ship-board experiments that manipulate seawater pH to assess the impacts on sea ice biota and their exopolymer polysaccharide products. Although previous work has focused on the impact of elevated CO2 on phytoplankton, there has been little targeted research on ice-dependent biota. Given the paucity of CO2 system observations in the central Arctic basin, especially late in the productive season when the impact of autumn production and the seasonal salinity minimum can be included in the cumulative estimate of production, the observations proposed here will be of particular significance.