Collaborative Research: Distribution and Cycling of Carboxyl-Rich Alicyclic Molecules (CRAM) in the Ocean

富羧基脂环分子（CRAM）在海洋中的分布与循环。溶解有机质是海洋中最大的有机碳库。因此，它在碳储存和气候变化中起着重要作用。溶解有机物的成分是生物制品的残留物。因此，溶解有机物（DOM）的化学组成可以为影响该碳库的过程提供重要线索。通过更多地了解产生DOM的化学结构和反应，可以将其与生物和生化过程及其重要性联系起来。该项目将研究一类重要的分子——富羧基脂环分子（CRAM）的分布、生产和去除。这些分子在海洋DOM中含量丰富，在海洋碳循环中起着重要作用。它们还影响微量营养素铁的供应，从而对初级生产和海洋食物网产生重要影响。这项研究包括实地和实验室实验，并利用海洋位置的长期数据。两位首席科学家将共同为研究生提供培训和资源，为STEM中代表性不足的群体提供本科生研究机会，并通过网站、当地报纸上的文章和公共场所的演讲直接与公众接触。CRAM构成了海洋溶解有机碳（DOC）的8 - 25%，代表了65 Pg C的碳库，相当于至少8%的大气CO2库。CRAM在微生物碳泵的功能中起着核心作用，微生物碳泵是海洋中微生物过程产生难降解碳的概念框架。此外，CRAM作为海洋中Fe（III）的重要配体，在调节海洋初级生产中发挥着重要作用。该项目的主要目标是：(1)测量海洋中CRAM的变化分布；(2)确定CRAM产生和去除的主要机制。该项目将利用已经在世界海洋中收集的大量样本，并在百慕大、大西洋和夏威夷海洋时间序列的框架内进行新的实地工作。现场测量将与实验方法相结合，专门解决导致CRAM产生和去除的微生物和光化学反应。本研究将填补解决海洋有机碳循环关键问题的重要空白，探索DOM在调节铁等微量元素循环中的作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Collaborative Research: Distribution and Cycling of Carboxyl-Rich Alicyclic Molecules (CRAM) in the OceanDissolved organic matter is the largest pool of organic carbon in the ocean. Thus, it plays an important role in carbon storage and climate change. The components of dissolved organic matter are the remains of biological products. As a result, the chemical make-up of dissolved organic matter (DOM) can provide important clues about the processes affecting this carbon pool. By learning more about the chemical structures and reactions that produce DOM, connections can be made to biological and biochemical processes and their importance. This project will study the distribution, production, and removal of one important class of molecules called carboxyl-rich alicyclic molecules (CRAM). These molecules are abundant in marine DOM and play an important role in the ocean carbon cycle. They also affect the supply of the micronutrient iron, and thus have an important influence on primary production and ocean food webs. The research includes field and laboratory experiments and takes advantage of ocean locations with long-term data. Together, the lead scientists will provide training and resources for the graduate students, undergraduate research opportunities for underrepresented groups in STEM, and direct outreach to the public through a website, articles in local newspapers, and talks at public venues. CRAM make-up 8 to 25% of marine dissolved organic carbon (DOC) and represent a carbon reservoir of 65 Pg C that is equivalent to at least 8% of the atmospheric CO2 pool. CRAM play a central role in the functioning of the microbial carbon pump, a conceptual framework for producing refractory carbon by microbial processes in the ocean. Further, CRAM act as an important ligand of Fe(III) in the ocean, thereby playing an important role in regulating marine primary production. The main project objectives are: (1) measure the variable distribution of CRAM in the ocean, and (2) determine the dominant mechanisms of CRAM production and removal. The project will leverage an extensive set of already collected samples across the world’s oceans and new field work within the framework of the Bermuda Atlantic and Hawaii Ocean Time Series. Field measurements will be combined with experimental approaches to specifically address microbial and photochemical reactions leading to CRAM production and removal. This research will fill important gaps in resolving the key questions about organic carbon cycling in the ocean and explore the role of DOM in mediating the cycles of iron and other trace elements.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.