Production and Fate of Fats in the Upper Ocean

上层海洋中脂肪的产生和命运浮游植物是海洋中的微小光合作用生物，它会产生一种称为三酰甘油(TAG)的脂肪。最近在北太平洋的一项发现表明，浮游植物初级生产量的很大一部分用于生产标签。这表明，在浮游植物无法从光合作用中产生能量的晚上，TAG可能是它们的能量来源。浮游植物是海洋食物网的基础。因此，了解它们是如何创造和储存能量是很重要的。这个项目将调查脂肪在海洋中的作用。具体地说，这项研究将着眼于：1)影响浮游植物生产和使用标签的因素，以及2)标签对全球碳循环的贡献。该项目将支持研究生的培训和教育。该项目还将为高中生提供指导资源，支持高中生和本科生的暑期研究体验，并为七年级学生提供实地考察。三酰甘油(TAG)是海洋中含量最丰富的类脂之一。一项新的发现表明，标签也是一种非常有活力的生物化学物质。最近对北太平洋副热带环流(NPSG)表层水域的一项研究表明，在日出到日落之间，TAG的浓度每天翻一番，占真核微型浮游植物初级净生产量的16%至42%(Becker等人，2018年)。这些结果表明，TAG是真核浮游植物生理学的重要组成部分，并且TAG对NPSG的碳循环有重要贡献。根据这项研究的估计，副热带环流白天的TAG产量占全球初级生产总量的4%至6%。在亚热带环流之外，TAG的生产率是完全未知的，特别是在初级生产率更高、真核浮游植物更占优势的地区。因此，TAG对全球海洋碳循环的贡献几乎肯定被低估了。有一些关于标签的主要悬而未决的问题。哪些环境因素会影响净标签生产率？净标签产量中有多大比例以下沉颗粒的形式出口？标签在真光区的食物网中起作用了吗？白天产生的标签有多少在晚上被浮游植物自己吃掉？这些问题将通过最先进的脂质组学、原位观察、同位素示踪技术、孵化和甲板实验来回答。这项研究将在我们对浮游植物中TAG新陈代谢的理解方面取得重大进展，阐明TAG在海洋碳循环中所扮演的角色，通过在多个不同环境中研究TAG来限制它们的全球重要性，并为未来对这些迷人而重要的分子的研究奠定基础。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The Production and Fate of Fats in the Upper Ocean Phytoplankton, microscopic photosynthetic organisms in the ocean, produce a type of fat called triaclyglycerols (TAGs). A recent discovery in the North Pacific Ocean showed that a significant percentage of primary production from phytoplankton is devoted to producing TAGs. This suggests that TAGs may serve as a source of energy for phytoplankton at night, when they are unable to generate energy from photosynthesis. Phytoplankton are the base of the food web in the ocean. Therefore, it is important to understand how they create and store energy. This project will investigate the role of fats in the ocean. Specifically, this research will look at: 1) factors that affect the production and use of TAGs by phytoplankton and 2) how TAGs contribute to the global carbon cycle. This project will support the training and education of graduate students. This project will also provide resources for mentoring high school students, support summer research experiences for high school and undergraduate students, and offer field trips for 7th grade students. Triacylglycerols (TAGs) are one of the most abundant classes of lipids in the ocean. A new discovery suggests that TAGs are also a very dynamic class of biochemicals. A recent study in the surface waters of the North Pacific subtropical gyre (NPSG) showed that TAGs doubled in concentration between sunrise and sunset daily, accounting for 16 to 42% of net primary production by eukaryotic nanophytoplankton (Becker et al., 2018). These results show that TAGs are an vital component of the physiology of eukaryotic phytoplankton and that TAGs contribute significantly to the carbon cycle of the NPSG. Based on estimates from this study, daytime production of TAGs in the subtropical gyres accounted for 4 to 6 percent of total global primary production. Outside of subtropical gyres, the production rates of TAGs are entirely unknown, particularly in regions where primary production rates are higher and eukaryotic phytoplankton are more dominant. Thus, the contribution of TAGs to the global ocean carbon cycle is almost certainly underestimated. There are major outstanding questions about TAGs. What environmental factors affect rates of net TAG production? What fraction of net TAG production is exported in sinking particles? Do TAGs play a role in the food web of the euphotic zone? How much of the TAGs produced during the day do phytoplankton themselves consume at night? These questions will be answered using state-of-the-art lipidomics, in situ observations, isotope-tracing techniques, incubations, and on-deck experiments. This study will provide significant advances in our understanding of TAG metabolism in phytoplankton, elucidate the roles that TAGs play in the marine carbon cycle, constrain their global importance by studying TAGs in multiple disparate environments, and set the groundwork for future research on these fascinating and vital molecules.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.