Collaborative Research: Dynamics of dissolved organic phosphorus production, composition and bioavailability along a natural marine phosphate gradient

合作研究：沿天然海洋磷酸盐梯度溶解有机磷产生、组成和生物利用度的动态

基本信息

批准号：
1756964
负责人：
Kathleen Ruttenberg
金额：
$ 71.8万
依托单位：
University of Hawaii
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-03-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1756964&HistoricalAwards=false
关键词：
Collaborative Research Dynamics dissolved organic

项目摘要

Phytoplankton, also known as primary producers, are microscopic floating plants at the base of the marine food web. As photosynthetic organisms, phytoplankton directly take up dissolved inorganic carbon (DIC) to synthesize their tissues using energy from the sun. In addition to carbon (C), essential nutrients such as phosphorus (P) and nitrogen (N) are required by these primary producers. While dissolved inorganic phosphorus (DIP) is the preferred form of P because it is a small enough molecule that phytoplankton can directly absorb it, in the sunlit surface waters of the ocean the concentration of DIP can be drawn down to limiting levels. In this situation, the larger dissolved organic phosphorus (DOP) molecules can become available through enzyme hydrolysis reactions, which convert DOP to DIP. There was mounting evidence that DOP can play a crucial role in supporting primary production in the ocean, yet very little is known about the nature of the DOP pool. There are many analytical impediments to gaining information about the chemical structure and composition of DOP, and without knowledge of its composition there is no basis for evaluating the potential bioavailability of DOP to primary producers. The proposed work will employ a unique combination of methods to gain novel insight into the composition and bioavailability of DOP. Field and laboratory (culture) nutrient addition incubation experiments will target the drivers of DOP variability, information crucial to resolving models of primary production in the ocean. Results of this work will be transformative for understanding DOP composition, DOP variability in space and time, and microbial control on the nature of the marine DOP pool. This proposal will support a postdoctoral scholar, two undergraduate students and two undergraduate students. Recruitment of undergraduate students will focus on entraining Native Americans and Pacific Islanders, through SACNAS (Society for Advancement of Chicanos/Hispanics and Native Americans in Science) and related venues. Results will be published in peer-reviewed journals and presented at national and international meetings. We also propose to conduct outreach to middle schools, including bringing The Artistic Oceanographer Program, an interactive inquiry-based program targeting middle school age science and art standards by integrating concepts in ocean science literacy with art, to local middle schools in New York and Hawaii.The proposed work will provide foundational information on the way DOP molecular characteristics translate into P-bioavailability to marine microorganisms, and in turn how microorganisms growing under different dissolved inorganic nitrogen: dissolved inorganic phosphorus (DIN:DIP) impact the composition and bioavailability of DOP. A newly developed sequential ultrafiltration (SUF) method will be applied to samples collected along a natural P-gradient in the western North Atlantic. The SUF method quantitatively segregates and concentrates DOP into 4 molecular weight size classes, which can be subjected to bioavailability assays using phosphohydrolytic enzymes, and to liquid chromotography-mass spectrometry to provide detailed compositional information. Using these combined methods we will probe in situ DOP, the evolution of in situ DOP during shipboard incubations under different DIN:DIP, and the composition and bioavailability of DOP produced by organisms isolated from key stations along the natural phosphate gradient. Contrast of in situ patterns to those developed in controlled culture experiments using field isolates will be achieved by identifying cellular shifts in organic phosphorus biosynthesis pathways, and tracing how such shifts impact DOP composition. The combined methodological approach will provide unparalleled insight into DOP composition and bioavailability, addressing this major knowledge gap. Results of this work will be transformative for understanding DOP composition, DOP variability in space and time, and microbial control on the nature of the marine DOP pool. Such information is a prerequisite to building ecosystem models that capture the influence of P biogeochemistry on primary production and carbon cycling in aquatic systems.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.

浮游植物，也称为主要生产商，是海洋食品网底部的微观浮动植物。作为光合生物，浮游植物直接吸收溶解的无机碳（DIC），以使用来自太阳的能量合成其组织。除碳（C）外，这些主要生产者还需要诸如磷（P）和氮（N）之类的必需营养素。虽然溶解的无机磷（DIP）是P的首选形式，因为它是一个足够小的分子，可以直接吸收浮游植物，但在海洋的阳光表面水中，倾斜的浓度可以将其降低到限制水平。在这种情况下，较大的溶解有机磷（DOP）分子可以通过酶的水解反应可用，这些反应将DOP转化为DIP。有越来越多的证据表明，DOP可以在支持海洋的初级生产中发挥至关重要的作用，但对DOP池的性质知之甚少。有许多分析障碍可以获得有关DOP的化学结构和组成的信息，并且在不了解其组成的情况下，没有基础来评估DOP对主要生产者的潜在生物利用度。拟议的工作将采用独特的方法组合来获得对DOP的组成和生物利用度的新颖见解。现场和实验室（培养）养分添加孵化实验将针对DOP变异性的驱动因素，即对于解决海洋初级生产模型至关重要的信息。这项工作的结果将具有变革性，以理解DOP组成，空间和时间的DOP变异性以及对海洋DOP池性质的微生物控制。该建议将支持一所博士后学校，两名本科生和两名本科生。招募本科生将通过SACNA（奇卡诺斯/西班牙裔美国人和美国原住民的科学促进协会）和相关场所的招募，专注于美国原住民和太平洋岛民。结果将在同行评审的期刊上发表，并在国家和国际会议上发表。我们还建议对中学时代科学和艺术标准进行宣传。 We also propose to conduct outreach to middle school school age science and art standards integrating concepts in ocean science literacy with art, to local middle schools in New York and Hawaii.The proposed work will provide foundational information on the way DOP molecular characteristics translate into P-biovailability to marine microorganisms, and in turn how microorganisms grow under different dissolved inorganic nitrogen: dissolved inorganic phosphorus （DIN：DIP）影响DOP的组成和生物利用度。新开发的顺序超滤（SUF）方法将应用于沿北大西洋西部天然P级收集的样品。 SUF方法定量分离并将DOP浓缩为4个分子量大小类别，可以使用磷酸氢化酶进行生物利用度评估，并通过液相色谱 - 质量质谱法提供详细的组成信息。使用这些合并的方法，我们将原位探测原位DOP的演变，在不同的DIN下寄船过程中的原位DOP的演变以及由从沿天然磷酸盐梯度的关键站分离的生物体产生的DOP的组成和生物利用度。原位模式与使用场分离株在受控培养实验中开发的原位模式的对比，将通过鉴定有机磷生物合成途径的细胞移动来实现，并追踪这种转移如何影响DOP组成。合并的方法论方法将为DOP组成和生物利用度提供无与伦比的见解，从而解决这一主要知识差距。这项工作的结果将具有变革性，以理解DOP组成，空间和时间的DOP变异性以及对海洋DOP池性质的微生物控制。这种信息是建立生态系统模型的先决条件，该模型捕获了生物地球化学对水生系统中初级生产和碳循环的影响。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响标准来评估NSF的法定任务。