Adenosine triphosphate as a master variable for biomass in the oceanographic context

在海洋中，大多数生物都是微生物，它们太小了，肉眼看不见。尽管微生物体积很小，但它们在控制海洋生态系统和食物网的过程中发挥着重要作用。例如，微生物影响水和大气中营养物质和气体的浓度，从而对全球气候产生重大影响。因此，了解在任何给定环境中有多少微生物是很重要的，因为生物质量与总体生物活动之间存在直接的因果关系。然而，确定任何体积的水有多“活”是一项艰巨的任务。金标准是在显微镜下对微生物细胞进行计数。这种方法做得很好，非常耗时，需要在许多不同类型的微生物细胞上单独进行。此外，标准的显微镜技术并不能显示细胞在收集时是否活着。相比之下，基于三磷酸腺苷（ATP）数量的化学方法具有明显的优势。值得注意的是，ATP相对容易测量，并且该方法可以广泛使用，因为所有活细胞都含有相似浓度的ATP。本研究测试并应用了一种改进的ATP分析方法来生成空间和时间上非常高分辨率的数据。一名博士生和六名本科生将接受研究培训，该项目促进与欧洲科学家的国际研究合作。这项研究对世界海洋不同区域和深度的生物物质分布提供了更深入的了解。几十年前，三磷酸腺苷（ATP）被提出作为一种通用的生物量指标。然而，由于对细胞ATP浓度的误解，其在海洋学领域的应用受到限制。最近的证据表明，ATP作为一种水变性物，需要远高于能量代谢所需的稳态控制的ATP水平。ATP在各种微生物的细胞质中以惊人的稳定浓度存在，因此代表了活的细胞质体积。本项目详细研究了微粒ATP （PATP）作为北大西洋大部分地区生物量标记物的有用性，特别强调中远洋和深海环境，其中叶绿素是生物量或相关生物过程的不良指标。该项目使用海洋雪和环境水的现场收集，结合粒子相机来检查水柱中生物量的微观异质性。实验室研究通过过滤和提取方案确定可能影响PATP回收率的因素，并确定在磷限制期间ATP浓度可能偏离典型细胞质浓度的程度。改进的patp -生物质方法具有许多操作优势，特别是可以在高空间和时间分辨率下使用。一旦验证，PATP生物量方法可以作为常规海洋调查中生物量的关键变量被广泛采用。该项目支持来自不同背景的研究生和本科生参与实验室和实地研究。公众宣传工作包括为中学生和高中生以及公众提供参观和演讲。本项目由海洋科学部化学海洋学和生物海洋学项目资助。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。

In the ocean, most living organisms are microbes that are too small to be seen by the naked eye. Despite their small size, microbes play an important role in processes that govern marine ecosystems and food webs. For example, microbes affect the concentrations of nutrients and gases in the water and the atmosphere, thereby exerting a significant impact on the climate globally. Consequently, it is important to know how many microbes there are in any given environment because there is a direct causal connection between living mass and overall biological activity. Determining how “alive” any volume of water is, however, is a difficult task. The gold standard is to count microbial cells under the microscope. This method is extremely time consuming when done well and needs to be performed separately on many different types of microbial cells. In addition, standard microscopic techniques do not reveal whether the cells were alive when they were collected. In contrast, a chemical method based on the amount of adenosine triphosphate (ATP) offers distinct advantages. Notably, ATP is relatively easy to measure, and the method can be widely used because all living cells contain ATP in similar concentrations. This study tests and applies an improved method of ATP analysis to generate data at very high resolution in space and time. One PhD student and six undergraduate students will receive research training and the project fosters international research collaborations with European scientists. This research provides deeper insights into the distribution of live matter in different regions and depths of the world’s oceans. Decades ago, adenosine triphosphate (ATP) was proposed as a universal biomass indicator. However, its application in the field of oceanography has been limited due to misconceptions regarding cellular ATP concentration. Recent evidence suggests that ATP functions as a hydrotrope requiring homeostatically controlled ATP levels much higher than those solely needed for energy metabolism. ATP occurs in surprisingly stable concentrations in cytoplasm across a wide range of microbes thus representing live cytoplasm volume. This project examines in detail the usefulness of particulate ATP (PATP) as a biomass marker over a large section of the North Atlantic Ocean with special emphasis on mesopelagic and deep-sea environments where chlorophyll is a poor indicator of biomass or associated biological processes. The project uses field collections of marine snow and ambient water in combination with particle cameras to examine the microscale heterogeny of biomass in the water column. Laboratory studies determine factors that may influence the recovery of PATP through filtration and extraction protocols and determine to what extent ATP concentrations potentially deviate from the typical cytoplasm concentration during phosphorus limitation. The improved PATP-biomass method offers numerous operational advantages, especially the fact that it can be employed at high spatial and temporal resolution. Once validated, the PATP biomass method could be widely adopted as a key variable for biomass in routine oceanographic surveys. This project supports graduate and undergraduate students from diverse backgrounds to contribute to laboratory and field research. Public outreach efforts include tours and presentations for middle and high-school students, as well as the general public.This project is funded by the Chemical Oceanography and Biological Oceanography Programs in the Division of Ocean Sciences.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.