Beyond the unsaturation ratios (UK37&#39; or UK37) of long chain alkenones: unlocking the hidden treasure trove of alkenone-producing haptophytes

GSTDTAP

项目编号	1762431
	Beyond the unsaturation ratios (UK37' or UK37) of long chain alkenones: unlocking the hidden treasure trove of alkenone-producing haptophytes
	Yongsong Huang
主持机构	Brown University
项目开始年	2018
	2018-09-01
项目结束日期	2021-08-31
资助机构	US-NSF
项目类别	Standard Grant
项目经费	334447(USD)
国家	美国
语种	英语
英文摘要	The proposed research aims to bring and calibrate a new set of molecular tools that permit a more in-depth and quantitative understanding of underlying mechanism driving climate variations. The new molecular tools will overcome the problems of the existing methods that are extremely problematic in ocean settings close to continental margins and estuaries because of entangled molecular signals. Once calibrated, the new molecular indices will provide new ways to study past temperature variations at unprecedented details. The research also has great potential to establish novel molecular approaches that allow quantitative assessment of changes in sea surface salinity - a very important indicator of regional hydrological changes. The study will also greatly advance our understanding of biochemistry and genetic control of lipid biosynthesis in isochrysidales (a class of haptophyte algae that are among the most dominant photosynthetic organisms in the global oceans) in a wide range of ocean and continental environments. Specifically, lipids like alkenones and alkenoates are unique biomarkers produced by isochrysidales that not only permit quantitative past climate and environmental reconstructions, but are also regarded as among the top candidates for biodiesel production using algal biomass in the near future. The funds will also support graduate students who, together with the PIs, actively participate in a wide range of broad-impact activities such as teaching science at local GK-12 schools, many of which have substantial population of underrepresented minorities. The technical merit of the research can be summarized as follows. The unsaturation ratios (UK37' or UK37) of long chain alkenones (LCAs) are among the most successful paleo-sea surface temperature (SST) proxies ever developed, and have been widely applied for over three decades. A recent study by the PI, however, suggests that the true power of this important class of biomarkers has yet to be fully unleashed. For example, a newly discovered freshwater/oligosaline haptophyte species with characteristic alkenone profiles distinct from marine and saline water counterparts open up new opportunities for quantitative continental paleoclimate studies. Important recent progress made by the research team in both gas and liquid chromatographic separation of alkenones/alkenoates permits accurate, comprehensive and simultaneous quantification of up to 32 alkenones, alkenoates and their structural isomers (~5 - 10 times more compounds than old analytical methods) and a corresponding new suite of SST proxies based on isomeric ratios and non-C37 alkenones. These developments promise to extend alkenone proxies to previously inaccessible regions, including: 1) marginal seas where alkenones are contributed by both open-ocean and coastal species; 2) high latitude regions where alkenone concentrations are low and the traditional alkenone-temperature relationship fails. Comprehensive biomarker profiling has great potential to refine chemotaxonomic differentiation of different groups/species of alkenone-producing haptophytes, with implications for quantitative apportionment of species inputs in mixed aquatic settings and assessing past sea surface salinity (SSS) changes. This proposal aims to systematically analyze a large suite of core top ocean sediments, and to culture selected haptophyte species/key strain varieties, to calibrate the new SST and SSS proxies and to establish high quality biomarker profiles for chemotaxonomy. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/73309
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Yongsong Huang.Beyond the unsaturation ratios (UK37' or UK37) of long chain alkenones: unlocking the hidden treasure trove of alkenone-producing haptophytes.2018.