OCE-PRF: Metabolic Contributions to Climate Proxies and Untested Assumptions in the Hydrologic and Ecological Applications of Photoautotrophic Lipids

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项目编号	1520926
	OCE-PRF: Metabolic Contributions to Climate Proxies and Untested Assumptions in the Hydrologic and Ecological Applications of Photoautotrophic Lipids
	Wolhowe Matthew D
项目开始年	2015
	2015-10-01
项目结束日期	2017-09-30
资助机构	US-NSF
项目类别	Fellowship
项目经费	174000(USD)
国家	美国
语种	英语
英文摘要	Understanding how the Earth's hydrologic and carbon cycles will respond to climatic changes, whether as a result of warming, ocean acidification, or other trends, is an important charge of the oceanographic and Earth-sciences communities. Human adaptation to changes in these cycles rests on accurate prediction of those changes; accurate prediction, in turn, requires an understanding of the mechanisms involved. One of the best ways to discern these mechanisms is detailed investigation of past behavior via sedimentary records. In this project, the fellow will investigate the hydrogen isotopic composition of algal cell water in order to test important assumptions regarding environmental proxies currently being developed for such studies of past climate. The participation-broadening goals include producing and teaching material focused on the marine impacts of urban watersheds. This work will occur in collaboration with the Seattle chapter of MESA, a national organization dedicated to improving STEM education for economically disadvantaged youth, under-represented minorities, and women. The sponsoring scientist is Julian Sachs at the University of Washington College of the Environment. Unicellular marine or lacustrine photoautotrophs (both algae and photosynthetic bacteria) have generally been assumed to have internal water pools that are isotopically identical to that of their growth environment. This has spurred numerous attempts to develop hydrologic proxies from thehydrogen isotopic composition of sedimentary lipids produced by these organisms, as these compounds incorporate hydrogen from the intracellular water pool. It has also become clear that, in certain settings, the large and variable vital effects relating water and lipid isotopic compositions (quantified as the net fractionation factor alpha) potentially record a wealth of ecological information important for studies of the carbon cycle. The community faces a challenge in further development of these isotopic proxies, however, as recent work has suggested that growth or metabolic rate may exert significant controls on intracellular hydrogen isotopic composition of water. To address this, the fellow will run a series of experiments to determine the isotopic response of intracellular water in photoautotrophs to growth. A series of chemostat culture experiments will be coupled with the novel Kreuzer isotope enrichment technique employed in previous metabolic water determinations. These experiments are designed to isolate the effects of cell division, light intensity, salinity, and growth phase on the hydrogen isotopic composition of the water available for lipid synthesis, and to determine the degree to which any changes are propagated into lipids. The proposed work may resolve an important open question regarding the fidelity of a whole class of promising environmental proxies. The quantification of isotopic differences between environmental and intracellular water in photoautotrophs may open new avenues of research for biologists across many fields, however, as these differences may trace cellular synthesis, respiration, and water exchange processes.
来源学科分类	Geosciences - Ocean Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/68877
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Wolhowe Matthew D.OCE-PRF: Metabolic Contributions to Climate Proxies and Untested Assumptions in the Hydrologic and Ecological Applications of Photoautotrophic Lipids.2015.