SGER: Sampling and Isotopic Analysis of Yucatan Groundwater: Impact of Hurricane Isadore

本建议旨在评估热带风暴降水，特别是飓风降水作为地下水移动的天然示踪剂的使用情况。众所周知，热带风暴的降水具有特殊的氧和氢同位素组成，这使其有别于正常降水。由于热带风暴产生的降雨量也是正常风暴的数倍，它们能够在一次事件中向含水层中添加大量或大量的水。这项研究的目的是确定是否可以通过稳定的同位素测量来追踪同位素标记的水在含水层中流动的情况。这项研究可以建立一种强大的新技术来研究飓风频繁的热带地区的地下水。很难计划和建立一个适合监测飓风的实验，而建立一个庞大的监测站网络纯粹是因为该网络中的某个地方可能会发生热带风暴，这将是昂贵的。这就是这项提议的紧迫性所在。飓风伊莎多尔最近经过尤卡坦半岛北部，该地区的PI以前已经获得了关于当地地下水同位素组成的背景数据。尤卡坦北部特别适合试用这一监测技术：其岩溶含水层极具渗透性，确保地下水快速移动；几乎没有土壤可以阻止飓风降水快速进入含水层；含水层相对简单。因此，随着飓风降水的移动，监测该含水层中水的组成变化将相对容易。地下水样本将在一年内分三次抽样采集。这些将从市政水井、有盖的岩溶天坑和压力计(如果有)中获得。学生们将参与收集样本和分析数据。同位分析将在墨西哥国立自治大学的稳定同位素实验室进行。这个项目的智力价值将是更好地了解地下水这一宝贵资源的行为，并开发一种新的、无污染的技术来绘制其运动图。这项活动的更广泛的影响将包括：1)开发有关地下水运动的信息，以便更好地管理和保护非常敏感的尤卡坦含水层的地下水(对人类健康、农业生产力、工业发展和旅游业至关重要)；2)通过在这项研究中的密切合作，在墨西哥科学家和美国科学家之间建立更密切的合作；以及3)对学生进行教育，使他们了解收集有意义的地下水样本和评估这项研究的分析结果所使用的程序。

0313847PerryThis proposal is to evaluate the use of tropical storm precipitation,especially that from hurricanes, as a natural tracer of groundwatermovement. Precipitation from tropical storms is known to have a specialoxygen and deuterium isotope composition that distinguishes it fromnormal precipitation. Because tropical storms also produce many times asmuch rain as normal storms, they are capable of adding a large batch orslug of water to an aquifer during a single event. The objective of thisstudy is to determine whether that slug of isotopically labeled watercan be traced by stable isotope measurements as it moves through anaquifer. This research could establish a powerful new technique to studygroundwater in tropical areas where hurricanes are frequent. It is difficult to plan and set up an experiment suitable formonitoring a hurricane, and it would be expensive to establish a largenetwork of monitoring stations purely on the chance that a tropicalstorm might occur somewhere within that network. That is what adds anelement of urgency to this proposal. Hurricane Isadore recently passedover the northern Yucatan Peninsula, an area where the PI has previouslyobtained background data on the isotopic composition of the localgroundwater. Northern Yucatan is especially well suited for a trial ofthis monitoring technique: its karst aquifer is extremely permeable,insuring rapid groundwater movement; it has almost no soil that mightimpede rapid movement of the hurricane precipitation into the aquifer;and the aquifer is relatively uncomplicated. Thus, it will be relativelyeasy to monitor changes in the composition of water in this aquifer asthe hurricane precipitation moves through. Samples of groundwater will be collected in three sampling tripsover a period of one year. These will be obtained from municipal wells,covered karst sinkholes, and piezometers (where available). Studentswill be involved in collecting the samples and analyzing the data.Isotopic analyses will be performed in the stable isotope laboratory ofthe Universidad Nacional Autonoma de Mexico. Intellectual merit of this project will be a betterunderstanding of the behavior of groundwater, a precious resource, andthe development of a new, non-polluting technique for charting itsmovement. The broader impacts of this activity will include: 1)development of information on groundwater movement that can lead tobetter management and protection of groundwater in the very sensitiveYucatan aquifer (essential for human health, agricultural productivity,industrial development, and tourism), 2) establishment of closercollaboration between Mexican scientists and scientists in the UnitedStates, accomplished by close collaboration in this research, and 3)education of students in the procedures used to collect meaningfulsamples of groundwater and to evaluate the analytical results of thisstudy.