Expanded Calibrations and Standardization of the Phosphate Oxygen Isotope System

为了更好地促进分析和解释的磷酸盐氧同位素比值获得广泛和不断增长的范围内的自然系统目前正在研究和更极端的环境计划为未来的研究，在这里，我们提出了一系列全面的控制实验室校准和approximations的磷酸盐？水O-同位素系统，涵盖与自然系统和栖息在这些系统中的微生物相关的温度、pH和离子强度范围（例如，嗜热菌、嗜酸菌）。拟议研究的主要目标是：（1）改进和扩展PO 4-水O同位素分馏的校准，以涵盖环境条件（例如，温度，pH值）与广泛的自然系统和微生物（例如，（2）对溶解无机PO_4（DIP）氧同位素组成的不同分析方法进行直接比较;以及3）为PO 4氧同位素分析准备一套磷酸银标准品，以补充2002年准备的日益减少的库存，这些库存将分发给各实验室和科学界成员，实验室比较和同位素分析的各种方法的标准化。此外，我们提出了跨生命的主要领域（细菌，古生菌）和与常见代谢（例如，BSR，甲烷生成）和地质生物学上重要的群体（微生物垫形成anoxygenicphototrophs-紫色和绿色硫细菌;铁氧化和铁还原细菌）。拟议研究的一般方法将是进行受控实验室实验，以校准PO 4和水之间的氧同位素分馏，作为温度、pH值和离子强度的函数，并根据先前发表和完善的实验方案合成用于O同位素分析的新磷酸银标准。拟议的研究将主要解决磷酸盐氧同位素系统校准方面的不足之处，以及全社会对磷酸盐氧同位素标准和最近开发的分析方法的标准化/比较日益增长的需求。这些研究对氧同位素方法在低温地球化学中的许多正在进行的和未来的应用以及对P的地球生物学的研究至关重要。将受益于拟议研究结果的研究应用包括对PO 4 d18 OP生物特征的研究以及环境和样品中P的地球化学循环，范围从海洋水柱，土壤，沉积物，热液系统和受污染的含水层扩散到海底以下的深层生物圈;以及对细菌、特别是古生菌的PO 4代谢进行一般性研究，古生菌的磷代谢尚未得到详细研究。作为拟议研究的一部分，用于PO 4 O同位素分析的磷酸银标准品将通过耶鲁大学中心提供给更广泛的科学界。稳定同位素分析。此外，对天然沃茨中溶解无机磷分析方法的比较，将有利于当前和未来的研究人员利用d18 OP研究磷循环。拟议的研究将培养2名女性博士后助理：丽莎斯托特博士和博士Saejung Chang以及参与耶鲁皮博迪博物馆赞助的K-12教育项目的本科暑期实习生和大学预科生，其中共同PI Ruth Blake是定期撰稿人。拟议研究的结果将纳入耶鲁大学PI Blake和博士后助理丽莎斯托特教授的地球微生物学研究生和本科课程;以及在国家和国际会议上的公开演讲。这项研究也将用于K-12教师培训实习，通过耶鲁皮博迪博物馆的进化计划赞助。

To better facilitate analyses and interpretations of phosphate oxygen isotope ratio values obtained from the wide and growing range of natural systems currently under study and more extreme environments planned for future study, here we propose a series of comprehensive controlled laboratory calibrations and standardizations of the phosphate?water O-isotope system covering the range of temperature, pH and ionic strength relevant to natural systems and the microorganisms that inhabit these systems (e.g., thermophiles, acidophiles). The primary objectives of the proposed research are to:(1) Refine and extend calibrations of PO4-water O isotope fractionations to encompass environmental conditions (e.g., temperature, pH) relevant to the wide range of natural systems and microorganisms (e.g., extremophiles, archaea) currently under investigation;(2) Make direct comparisons among different published methods for analysis of the oxygen isotope composition of dissolved inorganic PO4 (DIP); and3) Prepare a suite of silver phosphate standards for PO4 oxygen isotope analysis to replenish waning stocks prepared in 2002 that will be distributed to various laboratories and members of the scientific community for inter-laboratory comparisons and standardization of various methods of isotopic analysis.Furthermore, we propose investigations of phosphate-water O-isotope systematics across major domains of life (bacteria, archaea) and associated with common metabolisms (e.g., BSR,methanogenesis) and geobiologically important groups (microbial mat-forming anoxygenicphototrophs--purple and green sulfur bacteria; iron-oxidizing and iron-reducing bacteria). The general approach to proposed research will be to conduct controlled laboratory experiments to calibrate oxygen isotope fractionations between PO4 and water as a function of temperature, pH, and ionic strength, and to synthesize new silver phosphate standards for O isotope analysis following previously published and well -established experimental protocols.Intellectual Merit: The proposed research will primarily address deficiencies in calibrations of the phosphate oxygen isotope system, and a growing community-wide need for phosphate oxygen isotopic standards and standardization/comparison of recently developed analytical methods. These studies are crucial to many ongoing and future applications of oxygen isotope methods in low-temperature geochemistry as well as to studies of the geobiology of P. Research applications that will benefit from results of the proposed research include research on PO4 d18OP biosignatures and the biogeochemical cycling of P in environments and samples ranging from the marine water column, soils, sediments, hydrothermal systems and contaminated aquifers to the sub-seafloor deep biosphere; as well as general research on the metabolism of PO4 by bacteria and especially archaea whose P metabolism has not been studied in detail.Broader impacts: The silver phosphate standards for O isotope analysis of PO4 that will synthesize as part of the proposed research will be made available to the wider scientific community through the Yale Center for Stable Isotope Analysis. Also the comparison of methods of analysis of dissolved inorganic PO4 in natural waters will benefit current and future researchers employing d18OP in studies of P cycling. The proposed research will train 2 female postdoctoral associates: Dr. Lisa Stout and Dr. Saejung Chang as well as undergraduate summer interns and pre-college students involved in K-12 educational programs sponsored by the Yale Peabody Museum to which Co-PI Ruth Blake is a regular contributor. Results from the proposed studies will be incorporated into graduate and undergraduate courses in Geomicrobiology taught by PI Blake and postdoctoral associate Lisa Stout at Yale University; as well as into public presentations given at both national and international meetings. This research will also be used in K-12 teacher training internships sponsored through the EVOLUTIONS program at the Yale Peabody Museum.