Biological carbon uptake and trace gas emissions in the polar oceans under a changing climate

气候变化下极地海洋的生物碳吸收和微量气体排放

• 批准号: 249921-2012
• 负责人: Tortell, Philippe
• 金额: $ 4.15万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=570770
• 关键词: Biological; carbon; uptake; trace; gas

The high latitude oceans of both the Northern and Southern hemispheres play a large role in controlling atmospheric concentrations of climate-active trace gases. These regions contribute disproportionately to oceanic CO2 uptake and exhibit large sea-air fluxes of dimethylsulfide (DMS), a biogenic gas which influences cloud formation and impacts the atmospheric radiation budget. Global modeling studies suggest that polar ocean CO2 and DMS cycles are likely to change significantly over the coming century in response to climate-dependent changes in sea ice cover, circulation patterns and biological productivity. However, the magnitude of these potential climate-dependent changes is very poorly constrained by direct observations. The proposed research program will collect fundamental data on biological carbon cycling in Antarctic and Arctic marine waters, and on the production of various climate-active gases (e.g. DMS, methane and nitrous oxide). The principle research objectives are to: 1) examine the influence of increasing sea surface temperature and pCO2 on primary productivity and phytoplankton species assemblage composition in Antarctic and Arctic marine waters; 2) quantify the spatial and temporal variability of biological oxygen saturation, pCO2 and DMS concentrations in Arctic and Antarctic polynyas over a range of hydrographic and sea ice conditions; 3) use isotope tracer experiments to quantify key production and consumption terms in the high latitude DMS cycle, and 4) measure methane (CH4) and nitrous oxide (N2O) concentrations and production rates in Arctic shelf waters in relation to surface water productivity and sea ice cover. Field surveys will be used to map the surface distribution of trace gases in the Southern Ocean and Arctic Ocean using membrane inlet mass spectrometry (MIMS) for high spatial resolution analysis, combined with GC-MS for high sensitivity analysis of discrete depth profile samples. Isotope tracer experiments using 13C and 2H labelled compounds will be used to follow the production and consumption of DMS through various metabolic pathways, while phytoplankton sensitivity to temperature and CO2 variability will be assessed using controlled field-based incubation experiments.

北半球和南半球的高纬度海洋在控制气候活性痕量气体的大气浓度中起着重要作用。这些区域会导致海洋二氧化碳吸收不成比例，并表现出二甲基硫化物（DMS）的大型海水通量，这是一种影响云形成并影响大气辐射预算的生物气体。全球建模研究表明，由于海冰覆盖，循环模式和生物生产力的气候变化，极地海洋二氧化碳和DMS周期可能会在未来世纪发生显着变化。然而，这些潜在的气候依赖性变化的大小受到直接观察的约束非常严重。拟议的研究计划将收集有关南极和北极海水中生物碳循环的基本数据，以及生产各种气候活性气体（例如DMS，甲烷和一氧化二氮）。主要研究目标是：1）检查南极和北极海水中海面温度升高和PCO2对初级生产力和浮游植物物种组成组成的影响； 2）在一系列水文和海冰条件下，量化生物氧饱和，PCO2和DMS浓度的生物氧饱和度，PCO2和DMS浓度的空间和时间变化； 3）使用同位素示踪剂实验在高纬度DMS周期中量化关键的生产和消耗项，4）在北极架子水域中测量甲烷（CH4）和一氧化二氮（N2O）浓度（N2O）浓度和生产率，与地表水生产率和海冰覆盖率有关。现场调查将用于绘制南大洋和北极海洋中痕量气体的表面分布，并使用膜入口质谱（MIMS）进行高空间分辨率分析，并与GC-MS结合使用GC-MS，以高灵敏度分析离散深度剖面样品。使用13C和2H标记化合物的同位素示踪剂实验将用于通过各种代谢途径遵循DMS的生产和消耗，而浮游植物对温度和CO2变异性的敏感性将使用基于控制的现场孵化实验来评估。