Collaborative Research: Triple oxygen isotopes as a new method to study water inputs and metabolism in wild animals

合作研究：三氧同位素作为研究野生动物水输入和代谢的新方法

• 批准号: 1941903
• 负责人: Seth Newsome
• 金额: $ 34.89万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1941903&HistoricalAwards=false
• 关键词: Collaborative; Research; Triple; oxygen; isotopes

All animals require water and energy to stay alive. Water is obtained from a variety of external sources (e.g., rivers, lakes, food), and internally as a byproduct of the chemical reactions that occur during the breakdown of food. Energy is obtained from food and is processed at a rate that limits everything an animal does: foraging and hunting, dispersing, competing with other individuals, reproducing, and other activities. Thus, assessing the contributions of different water sources to animal intake, and assessing animal rates of energy use, are critically important for understanding all aspects of animal function. However, measuring water inputs and energy use of wild animals is prohibitively difficult. Methods to date require capturing and handling animals at least two different times, or sampling every potential water source in a given habitat. These tasks are frequently impossible in the field, severely limiting the study of these important variables. To overcome this challenge, this project will develop the use of Δ17O measurements from a single sample of animal body water (Δ17OBW) to quantify the fractional contributions from external and internal sources to the body water pool of an animal. In addition, the fractional contribution of internal water will provide an index of the rate of energy use, because this internal water is created at a rate that directly reflects the rate of energy processing. The understanding of Δ17OBW from this project will create new opportunities to incorporate animal function into a broad variety of studies.The value of Δ17O reflects deviations in the relationship between δ17O and δ18O. For most animals, two sources provide 80–99% of the input into their body water: 1) drinking/food water that is ultimately sourced from precipitation and 2) metabolic water. These two inputs have relatively constant and strikingly different Δ17O values: drinking/food water Δ17O ≈ 0.030‰ and metabolic water Δ17O ≈ -0.450‰. Importantly, the Δ17O values of these sources exhibit little variation because they are determined by mass-independent fractionation processes that are not affected by changes in δ17O and δ18O values. This project will study animals in captivity to evaluate the influence of changes in exogenous water intake and metabolic rate on Δ17OBW. In addition, longitudinal changes in the Δ17OBW values of wild animals will be tracked during natural fluctuations in temperature and precipitation that will influence their water balance and metabolism. These Δ17OBW results will be compared to traditional approaches involving δ18O modeling and the doubly-labeled water technique. Finally, the analytical methods of Δ17O measurements will be optimized for biological samples, including organic tissues, which will reduce the costs and required expertise of this approach and promote its adoption by the ecophysiological and ecological research communities. The new understanding of Δ17OBW can be used to study animal responses to the shift towards a hotter, drier climate that is occurring in many regions of the planet, and to assess qualitative variation in field metabolic rate, a critical but notoriously difficult-to-measure variable.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.

所有动物都需要水和能量来维持生命。水可从多种外部来源获得（例如，河流，湖泊，食物），以及内部作为食物分解过程中发生的化学反应的副产品。能量是从食物中获得的，其加工速度限制了动物所做的一切：觅食和狩猎，分散，与其他个体竞争，繁殖和其他活动。因此，评估不同水源对动物摄入量的贡献，以及评估动物的能量使用率，对于了解动物功能的各个方面至关重要。然而，测量野生动物的水输入和能量使用非常困难。迄今为止的方法需要捕获和处理动物至少两次，或者在给定栖息地的每个潜在水源进行采样。这些任务在实地往往是不可能的，严重限制了对这些重要变量的研究。为了克服这一挑战，该项目将开发使用来自单个动物体液样本（Δ 17 OBW）的Δ 17 O测量值，以量化外部和内部来源对动物体内水池的贡献。此外，内部水的贡献率将提供能量使用率的指数，因为这种内部水是以直接反映能量处理率的速率产生的。从这个项目中对Δ 17 OBW的理解将为将动物功能纳入各种研究创造新的机会。Δ 17 O的值反映了δ 17 O和δ 18 O之间关系的偏差。对于大多数动物来说，两个来源提供了80-99%的输入到它们的体内的水：1）饮用/食物水，最终来自降水和2）代谢水。这两种输入具有相对恒定但显著不同的Δ 17 O值：饮用/食物水Δ 17 O为0.030‰，代谢水Δ 17 O为-0.450‰。重要的是，这些源的Δ 17 O值几乎没有变化，因为它们是由不受δ 17 O和δ 18 O值变化影响的质量无关分馏过程确定的。本项目将以圈养动物为研究对象，评估外源性水分摄入量和代谢率的变化对Δ 17 OBW的影响。此外，在影响野生动物水分平衡和代谢的温度和降水自然波动期间，将跟踪野生动物Δ 17 OBW值的纵向变化。这些Δ 17 OBW结果将与涉及δ 18 O建模和双标记水技术的传统方法进行比较。最后，Δ 17 O测量的分析方法将针对生物样品（包括有机组织）进行优化，这将降低该方法的成本和所需的专业知识，并促进其被生态生理学和生态学研究界采用。对Δ 17 OBW的新认识可用于研究动物对地球许多地区发生的更热，更干燥气候转变的反应，并评估田间代谢率的定性变化，一个关键的，但众所周知的困难，该奖项反映了NSF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进行评估，被认为值得支持审查标准。