Putting B-vitamins on the map: to what extent do they shape phytoplankton dynamics and biogeography in the global ocean?

维生素B(硫胺素，B1；生物素B7；钴胺，B12)是维持地球上生命的化学元素的所有生物转化所必需的有机分子。没有这些分子的活动，地球上生命的化学--正如我们所知--将会终结。在海洋系统中，B族维生素的可获得性还通过控制细菌和浮游植物的生长以及物种多样性来影响食物链的动态。由于许多能够制造多种B族维生素的生物缺乏合成其他B族维生素的能力，它们的维生素需求和环境可获得性可能决定哪些特定的浮游植物物种在何时何地繁盛。因此，自然界中的浮游生物群落需要在相互依存的复杂马赛克中不断分享B族维生素。尽管早在20世纪40年代就发现了它们的相关性，但目前大多数海洋维生素研究仍然基于实验室实验或研究，重点是添加B-维生素对藻类和细菌的生物反应。然而，维生素在世界海洋中的分布大多是未知的，因为它们只在几个海洋盆地中进行了测量。因此，它们在浮游植物群落中的自然分布的实际效果至今仍是一个谜。该项目的主要目标是阐明B-维生素的可用性对世界海洋表层水域不同浮游植物物种空间分布的影响。需要这些数据来开始解开微生物浮游生物通过维生素交换相互联系的规则，并确定这些基本相互关系如何控制浮游植物和细菌生长等表层海洋生态系统的功能。归根结底，了解这些控制及其动态对于预测未来海洋环境的变化至关重要。在未来的温室世界中，海洋预计将是至关重要的，它提供了培育未来人类种群所需的蛋白质，并通过具有不同维生素需求的光合作用生物对其的吸收来减少人类产生的大气二氧化碳水平。这项研究旨在建立世界海洋表层水中维生素B分布的第一张全球地图，该地图是在马拉斯皮纳环航探险队期间收集的。这张维生素的全球地图正被用来确定它们在浮游植物物种生物地理学上的重要性，这仍然是一个悬而未决的生态之谜。这项研究的另一个目标是确定环境中的维生素浓度以及生物活性微量元素和常量营养素如何促进海洋表面不同真核和原核浮游生物物种的相对丰度的变化。总体而言，这是关于B-维生素在包括海洋环流在内的亚热带和热带开阔海洋环境中对生态系统功能和物种组成的作用的第一项全球研究。研究人员正在大西洋、太平洋和印度洋的几个全球分布的站点进行有针对性的元基因组分析，以确定浮游生物群落中的B族维生素合成者和消费者。马拉斯皮纳探险的数百名参与者已经生成了大量的数据集，完全可以用来解释维生素的结果。这项研究使我们能够扩大我们对全球范围内维生素B分布的理解，并进一步调查表层海洋的浮游生物群落动态是如何与环境中的维生素B池交织在一起的。这一奖项反映了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。

B-vitamins (thiamin, B1; biotin B7; cobalamin, B12) are organic molecules necessary for all the biological transformations of the chemical elements that support life on Earth. Without the activity of those molecules, the chemistry of life on Earth—as we know it—would end. In marine systems, the availability of B-vitamins also affects food web dynamics by controlling both bacterial and phytoplankton growth and species diversity. Because many organisms that can make several B-vitamins lack the ability to synthesize others, their vitamin needs and environmental accessibility could define which, when, and where specific phytoplankton species flourish. As a result, planktonic communities in nature need to constantly share B-vitamins in a complex mosaic of interdependencies. Despite the early discovery of their relevance in the 1940s, most current marine vitamin research is still based on laboratory experiments or studies focusing on the biological responses of B-vitamin additions on algae and bacteria. Yet, vitamin distributions in the world ocean are mostly unknown, as they have only been measured in a few marine basins. Thus, the actual effect of their natural distributions in phytoplankton communities is still a mystery today. The main goal of this project is to elucidate the effects of B-vitamins availability on the spatial distributions of different phytoplankton species in surface waters of the world ocean. These data are needed to start untangling the rules by which members of the microbial plankton are interconnected through vitamin exchange and to determine how these essential interrelations may control surface ocean ecosystem functioning, such as phytoplankton and bacterial growth. Ultimately understanding these controls and their dynamics is critical to predicting future changes in the marine environment. In the future greenhouse world, the ocean is expected to be of paramount importance, providing the required protein to nurture future human populations and to reduce the levels of human-produced atmospheric CO2 through its uptake by photosynthetic organisms with different vitamin requirements. This study is to establish the first global map of B-vitamin distributions in surface waters of the world ocean collected during the Malaspina circumnavigation expedition. This global map of vitamins is being used to determine their importance on phytoplankton species biogeography, a still unresolved ecological riddle. Another objective of the study is to establish how ambient vitamin concentrations, combined with bioactive trace elements and macronutrients, promote changes in the relative abundance of different eukaryotic and prokaryotic plankton species on the surface ocean. Overall, this is the first global study on the role of B-vitamins on ecosystem functioning and species composition in subtropical and tropical open ocean environments including the ocean gyres. The investigators are carrying out targeted metagenomic analyses to identify B-vitamins synthesizers and consumers within the planktonic community at several globally distributed stations across the Atlantic, Pacific, and Indian oceans. The extensive datasets already generated by the hundreds of participants of the Malaspina expedition is fully available to interpret the vitamin results. This study allows us to expand our understanding of B-vitamin distributions on a global scale and further investigate how surface ocean’s plankton community dynamics are intertwined with ambient B-vitamin pools.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.