CAREER: Biologically-Mediated Molecular-Level Transformations of Marine Organic Matter

职业：海洋有机物的生物介导的分子水平转化

• 批准号: 0529101
• 负责人: Elizabeth Kujawinski
• 金额: $ 33.73万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-12-31 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0529101&HistoricalAwards=false
• 关键词: CAREER; Biologically; Mediated; Molecular; Level

ABSTRACTOCE- 0346815The route from fixation of carbon by photosynthesis in the euphotic zone to its ultimate burial in bottom sediments or remineralization at depth is extremely complex and circuitous, involving biotic and abiotic processes acting differently on various compound classes and particle size fractions. A critical step in the pathway from fixation to burial / sequestration is the remineralization of small particulate organic matter (POM) and colloidal / dissolved organic matter (C/DOM) by the microbial loop, a group of microorganisms including bacteria and protozoan grazers. This group of microbes plays an integral role in the remineralization and modification of organic carbon compounds in all areas of the ocean, from coastal eutrophic areas to open-ocean oligotrophic regimes. Though this role of the microbial web in OM cycling in the coastal and open ocean has been well-established, molecular-level understanding of the transformations within different pools of organic matter (OM) has not been possible due to analytical limitations.In this study, a researcher at Barnard College will examine these transformations using isotope-ratio gas chromatography/ mass spectrometry (irGC/MS) and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Laboratory cultures of protozoa, bacteria and/or phytoplankton will be monitored for changes in OM composition as a function of time. The prey cultures will be isotopically-labeled with either C13-acetate (bacterial prey) or C13-bicarbonate (phytoplankton prey). Incorporation of the C13-label from prey material will be tracked through the protozoan digestive process and the lability of different OM fractions within grazing cultures can be estimated. Laboratory results will be extended to the field with incubations of size-fractionated seawater from coastal (NY) and oligotrophic (Bermuda) environments. By monitoring OM components on a molecular level, this study has an unprecedented opportunity to elucidate mechanisms for carbon preservation in the marine environment.This CAREER award will strengthen interdisciplinary training for undergraduate students at Barnard College and increase the number of young female scientists who enter the environmental science pipeline and continue on to graduate school in environmental chemistry.

从光合作用在真光层中固定碳到最终埋藏在海底沉积物中或在深层再矿化的过程是极其复杂和迂回的，涉及到生物和非生物过程对不同的化合物类别和粒度组分的不同作用。在从固定到埋藏/封存的过程中，一个关键步骤是微生物环(包括细菌和原生动物食草动物在内的一组微生物)对小颗粒有机物(POM)和胶体/溶解有机物(C/DOM)的再矿化。这组微生物在海洋所有区域，从沿海富营养区到远洋少营养区的有机碳化合物的再矿化和修饰方面发挥着不可或缺的作用。尽管微生物网在沿海和开阔海域有机质循环中的这种作用已经得到了很好的证实，但由于分析的限制，分子水平上还不可能了解不同有机质(OM)池内的转化。在这项研究中，巴纳德学院的一名研究人员将使用同位素比值气相色谱/质谱仪(IRGC/MS)和电喷雾电离傅立叶变换离子回旋共振质谱仪(ESI FT-ICR MS)来研究这些转化。将监测实验室培养的原生动物、细菌和/或浮游植物的有机质组成随时间的变化。猎物培养物将用C13-醋酸酯(细菌猎物)或C13-重碳酸盐(浮游植物猎物)进行同位素标记。将通过原生动物的消化过程跟踪来自猎物材料的C13标记的加入，并可以估计放牧培养物中不同OM组分的稳定性。实验室结果将通过培养来自沿海(纽约)和营养稀少(百慕大)环境的分级海水而推广到现场。通过在分子水平上监测有机质组分，这项研究有了一个前所未有的机会来阐明海洋环境中碳保存的机制。这一职业奖项将加强巴纳德学院本科生的跨学科培训，并增加进入环境科学管道并继续环境化学研究生院的年轻女科学家的数量。