Collaborative Research: Does competition for nitrogen between autotrophs and heterotrophs control carbon fluxes in the western coastal Arctic?

合作研究：自养生物和异养生物之间对氮的竞争是否控制了北极西海岸的碳通量？

• 批准号: 0909647
• 负责人: Marc Frischer
• 金额: $ 35.61万
• 依托单位: Skidaway Institute of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0909647&HistoricalAwards=false
• 关键词: Collaborative; Research; Does; competition; nitrogen

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Frischer 0909647Skidaway Institute of OceanographyUnds are provided to investigate the microbial controls on the productivity of a coastal Arctic ecosystem by focusing on the competition between autotrophs and heterotrophs for nitrogen (N). In the winter and summer waters near Barrow, Alaska, supplemented with complementary international research opportunities, the PIs propose to measure in situ concentrations of key microbial and biogeochemical constituents, relevant uptake activities, and expression of key N cycling genes to address two hypotheses:H1: The balance of autotrophy and heterotrophy in the Arctic is regulated both temporally and spatially by nitrate (NO3ˉ) and light.? Phytoplankton out-compete heterotrophic bacteria for NO3ˉ during the well-lit spring and summer conditions.? Heterotrophic bacterial uptake of NO3ˉ will be greater during the dark winter and under sea ice than in open water or well-lit summer conditions when bacteria are replete with phytoplankton-derived DON.? NO3 -, combined with terrestrial DOC derived from riverine and groundwater flow, may provide the means for bacterial growth and respiration during the dark winter.H2: Microbial community structure will vary according to the seasonal light cycle and the sources of available N. The observed lag in bacterial response to phytoplankton growth is due to a community shift.? Bacterial community composition will vary significantly between winter and summer.? The composition and dynamics of bacterial communities will correspond to concentrations and sources of N.? The expression of key N-cycling genes, N-uptake and regeneration, and DON uptake kinetics will vary with season and community composition.

该奖项是根据2009年的《美国恢复和再投资法》（公法111-5）进行资助的。Frischer0909647Skidaway海洋学研究所提供了对沿海北极生态系统生产力的微生物控制，通过专注于自动营养和nitrophs之间的竞争，来调查沿海北极生态系统的生产力。在阿拉斯加巴罗附近的冬季和夏季水域，补充了补充国际研究机会，PIS建议测量关键的微生物和生物地球化学成分的原位浓度（NO3＆＃713;）和光。植物浮游生物的材料异养细菌NO3＆＃713;在光线充足的春季和夏季。 NO3＆＃713;在黑暗的冬季和海冰下，比在露天水或夏季良好的夏季条件下要大的情况大，当时细菌充满了浮游植物的唐。 No3-，结合河流和地下水流的陆地文档，可能为黑暗冬季期间细菌生长和呼吸提供手段。细菌群落的组成在冬季和夏季之间会有很大差异。细菌群落的组成和动力学将对应于n的浓度和来源。关键的N周期基因，N摄取和再生的表达以及Don uttake动力学的表达会随季节和社区组成而变化。