Microbial Oceanography Links to New aerosols in Ice-covered Regions (MjOLNIR) in the Arctic Ocean

微生物海洋学与北冰洋冰覆盖区域新气溶胶 (MjOLNIR) 的联系

• 批准号: 1736783
• 负责人: Giacomo DiTullio
• 金额: $ 68.29万
• 依托单位: College of Charleston
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736783&HistoricalAwards=false
• 关键词: Microbial; Oceanography; Links; New; aerosols

The most dramatic environmental changes occurring on the Earth today are taking place in the Arctic Ocean. Recent models predict that complete summertime Arctic sea ice loss will likely occur in the first half of the 21st century. The rapidly-declining areal expanse of summer pack ice will lead to changes in microbial community structure and production within both sea-ice communities and in the open waters of the Arctic Ocean. As summer sea ice microbial communities are replaced by open ocean populations, identifying changes in chemical compounds, such as various aerosols, that are released to the atmosphere might play a significant role in determining the future rate and impact of sea ice decline. The aerosols produced by microorganisms will ultimately move across the sea to air boundary and could affect cloud formation and with feedbacks that impact the Arctic system. In this study, the investigators will use state-of-the art methods to measure the relative abundances of aerosols that are associated with the microbial communities found in sea ice, melt ponds, sea ice leads, and in the open ocean. Better understanding of the changes in the structure of these microbial communities will provide new information for the next generation of models and may lead to more sophisticated understanding of various climate feedback loops. In addition, the project involves a collaboration with Swedish polar researchers and will strengthen scientific linkages between scientists in the USA and Sweden. The project will support training for graduate and undergraduate students, and the investigators will share research results with the public through lectures, as part of the Cultivate Program, and social media. The investigators will investigate how in-situ microbial community composition and productivity in contrasting sea-ice and open-ocean Arctic ecosystems impact the production and release of biogenic, volatile organic carbon (VOC) compounds. These VOC compounds are instrumental in the release and production of aerosols that ultimately form cloud condensation nuclei. In addition, the investigators will perform shipboard manipulative experiments to determine the effects of elevated sea surface temperatures, enhanced light intensities, and lower salinities resulting from melting sea ice and enhanced water column stratification. These changes will impose physiological stress on microbial communities that is likely to impact both phytoplankton community structure and the flux of the biogenic sulfur trace gas dimethylsulfide (DMS). The investigators will test how temperature, salinity, and light will affect the composition of the microbial community and thereby the catabolic fate of the DMS precursor dimethylsulfoniopropionate (DMSP), to yield either DMS or methanethiol and methane (CH4). In addition, the investigators will test whether the high CH4 concentrations observed in Arctic Ocean surface waters are due to DMSP catabolism or, alternatively, the breakdown of methylphosphonate. Using state-of-the-art instrumentation, they will monitor VOC fluxes using a shipboard Proton Transfer Reaction Mass Spectrometer (PTR-MS), a Membrane Inlet Mass Spectrometer, and high speed sorting flow cytometer to measure VOCs, net community production, and microbial community composition, respectively. They will make direct measurements of VOCs within sea ice by using a newly developed ice crusher attached to the PTR-MS to provide new in-situ data on the concentrations of DMS and CH4 in sea ice communities.

当今地球上发生的最剧烈的环境变化发生在北冰洋。最近的模型预测，北极海冰在21世纪上半叶可能会完全消失。夏季浮冰面积的迅速缩小将导致海冰群落和北冰洋开阔水域微生物群落结构和生产的变化。随着夏季海冰微生物群落被开阔的海洋种群所取代，确定释放到大气中的化合物（如各种气溶胶）的变化可能在确定未来海冰减少的速度和影响方面发挥重要作用。微生物产生的气溶胶最终将越过海洋到达空气边界，并可能影响云的形成，并产生影响北极系统的反馈。在这项研究中，研究人员将使用最先进的方法来测量气溶胶的相对丰度，这些气溶胶与在海冰、融化池、海冰铅和开阔海洋中发现的微生物群落有关。更好地了解这些微生物群落结构的变化将为下一代模型提供新的信息，并可能导致对各种气候反馈回路的更复杂的理解。此外，该项目涉及与瑞典极地研究人员的合作，并将加强美国和瑞典科学家之间的科学联系。该项目将支持对研究生和本科生的培训，研究人员将通过讲座和社交媒体与公众分享研究成果，作为“培养计划”的一部分。研究人员将调查对比海冰和开放海洋北极生态系统中原位微生物群落组成和生产力如何影响生物源性挥发性有机碳（VOC）化合物的产生和释放。这些挥发性有机化合物有助于气溶胶的释放和产生，最终形成云凝结核。此外，调查人员还将进行船上操作实验，以确定海面温度升高、光照强度增强以及海冰融化和水柱分层增强所导致的盐度降低的影响。这些变化将对微生物群落施加生理压力，可能影响浮游植物群落结构和生物源硫微量气体二甲基硫（DMS）的通量。研究人员将测试温度、盐度和光照如何影响微生物群落的组成，从而影响DMS前体二甲基磺酰丙酸（DMSP）的分解代谢命运，从而产生DMS或甲硫醇和甲烷（CH4）。此外，研究人员将测试在北冰洋表面水域观察到的高浓度CH4是由于DMSP分解代谢，还是甲基膦酸盐的分解。他们将使用最先进的仪器，分别使用船上的质子转移反应质谱仪（PTR-MS）、膜入口质谱仪和高速分选流式细胞仪来监测挥发性有机化合物的通量，分别测量挥发性有机化合物、净群落产量和微生物群落组成。他们将使用PTR-MS附带的新开发的碎冰机直接测量海冰内的挥发性有机化合物，以提供海冰群落中DMS和CH4浓度的新原位数据。

项目成果

Biogeochemical and ecological variability during the late summer–early autumn transition at an ice‐floe drift station in the Central Arctic Ocean

北冰洋中部浮冰漂移站夏末初秋过渡期间的生物地球化学和生态变化

• DOI: 10.1002/lno.11676
• 发表时间: 2020
• 期刊: Limnology and Oceanography
• 影响因子: 4.5
• 作者: Schanke, Nicole L.;Bolinesi, Francesco;Mangoni, Olga;Katlein, Christian;Anhaus, Philipp;Hoppmann, Mario;Lee, Peter A.;DiTullio, Giacomo R.
• 通讯作者: DiTullio, Giacomo R.