Influence of hydrography and microbial processes on the cycling of sea ice-associated material in the Arctic

北冰洋正在经历迅速的变化，包括海冰减少，温度和分层增加，以及水团的重新分布。这些变化从根本上影响生态过程，进而影响碳和物质的地球化学循环。重要的是，微生物群落结构的变化和细菌呼吸作用的增加会影响北冰洋的输出通量和CO2吸收能力。多年冰迅速减少，2012年达到新的最低记录，这也再次表明迫切需要更好地了解多年海冰与第一年海冰在北极碳和物质循环中的作用。预计在更温暖的北极，微生物活动将增加，同时，从多年冰到第一年冰的转变预计将改变微生物群落可用的有机物质的分布和组成。这项研究有兴趣更好地了解影响海冰相关社区的生产力和组成的因素，从而影响北冰洋的碳和元素循环。本研究的总体目标是：1）评估水文条件对北极海冰和冰下微生物群落的区域丰度、组成和活性的影响; 2）确定微生物过程和群落结构对海冰相关元素循环和输出的作用。这项研究将有助于更好地了解微生物群落对北极变化的反应，这对进一步预测全球碳循环至关重要。

The Arctic Ocean is experiencing rapid changes including sea ice decline, increase in temperature and stratification, and redistribution of water masses. These changes fundamentally impact ecological processes that, in turn, influence the biogeochemical cycling of carbon and materials. Of significance, changes in microbial community structure and increases in bacterial respiration influence export fluxes and the CO2 uptake capacity of the Arctic Ocean. The rapid decrease in multi-year ice, with a new record minimum in 2012, also reaffirms the urgency to better understand the role of multi-year versus first-year sea ice in the cycling of carbon and materials in the Arctic. Increased microbial activity is anticipated in a warmer Arctic and concomittantly, a shift from multi-year to first-year ice is expected to modify the distribution and composition of organic material available for microbial communities. This study is interested in better understanding the factors that influence the productivity and composition of sea ice-associated communities and thereby impact carbon and elemental cycling in the Arctic Ocean. The general objectives of this study are to: 1) evaluate the influence of hydrographic conditions on the regional abundance, composition, and activity of Arctic sea ice and underice microbial communities; 2) determine the role of microbial processes and community structure on sea ice-associated elemental cycling and export. This research will contribute to better understanding changes in microbial communities in response to Arctic changes, which is essential to further our predictive understanding of the global carbon cycle.