CAREER: Investigating the relationship between giant sulfur bacteria and microfossil-bearing phosphorites.

磷酸盐矿床以其对软组织的精致保护而闻名？包括被冻住的细胞大分隔丝被解释为最古老的真核生物保存在16亿年前的磷块岩从Vindhyan盆地在印度中部，和最古老的假定后生动物被保存为磷酸化对称细胞簇在6亿年前的陡山沱组在中国南部。有趣的是，大的空泡硫氧化细菌被认为是现代磷酸化的媒介，通常具有与文迪雅丝状体和陡山沱球状微体化石非常相似的形态。文德期或陡山沱期的微化石是否代表了空泡硫细菌，而不是真核生物？这些微体化石能否提供古代硫细菌对磷块岩进行调节的证据？在陡山沱微生物群的例子中，有些微化石显然是真核生物，很可能起源于后生动物，而另一些则不能轻易解释为动物？但细菌和动物的解释是相互排斥的吗？其他古代和近代的磷块岩矿床也具有很可能代表硫化细菌的结构，但尚未建立识别它们的标准。私家侦探？的研究小组将：1）研究新发现的部分埋藏于磷质矿物中的现代硫细菌，2）用现代硫细菌进行磷酸盐化实验，研究磷酸盐化细菌的埋藏学，3）将现代磷酸盐化硫细菌与元古宙和元古界磷块岩中的古微体化石进行比较，4）将现代磷酸盐化硫细菌与元古界和元古界磷块岩中的古微体化石进行比较，5）将现代磷酸盐化硫细菌与元古界和元古界磷块岩中的古微体化石进行比较，6）将现代磷酸盐化硫细菌与元古界和元古界磷块岩中的古微体化石进行比较，7）将现代磷酸盐化硫细菌与元古界和元古界磷块岩中的古微体化石进行比较，7）将现代磷酸盐化硫细菌与元古界和元古界磷块岩中的古微体化石进行比较，8）将现代磷酸盐化硫细菌与元古界和元古界磷块岩中的古微体化石进行比较。4）利用现代硫细菌的观察，建立区分巨型硫细菌化石和微生物真核生物化石的新标准-这项建议的研究部分与教育和推广计划密切相关，该计划开发了新的本科生和研究生课程，作为明尼苏达大学地球生物学课程的基础。一个研究生谁将在这里描述的项目工作也将支持和指导整个赠款期间。教育和推广计划还增加了退伍军人的研究机会，通过建立一个夏季研究经验的学生退伍军人，以及提供外展到高中学生和代表性不足的少数民族通过参与国家科学基金会资助的北星星干联盟，UMN探索职业生涯在工程和物理科学计划，以及墨西哥裔美国人和美洲原住民科学促进会的年会。

Phosphatic mineral deposits are well known for their exquisite preservation of soft tissue ? including fossilized cells. Large septate filaments interpreted as the oldest eukaryotes are preserved in 1.6 billion-year-old phosphorites from the Vindhyan Basin in Central India, and the oldest putative metazoans are preserved as phosphatized symmetrical cell clusters in the 600-milion-year-old Doushantuo Formation in southern China. Interestingly, large vacuolate sulfur-oxidizing bacteria are thought to mediate modern phosphogenesis, and commonly possess morphologies that closely resemble both the Vindhyan filaments and the Doushantuo globular microfossils. Could the Vindhyan or Doushantuo microfossils represent vacuolated sulfur bacteria, rather than eukaryotes? Could these microfossils provide evidence of the ancient mediation of phosphorites by sulfur bacteria? In the case of the Doushantuo microbiota, some microfossils are clearly eukaryotic, and likely metazoan in origin, while others cannot be easily interpreted as animals ? but are the bacterial and animal interpretations mutually exclusive? Other ancient and recent phosphorite deposits also possess structures that might well represent fossilized sulfur bacteria, but criteria for their recognition are not yet established. The PI?s research group will: 1) investigate newly-discovered modern sulfur bacteria that are partially entombed in phosphatic minerals; 2) perform phosphatization experiments with modern sulfur bacteria to investigate the taphonomy of phosphatized bacteria; 3) compare modern phosphatized sulfur bacteria with ancient microfossils from Proterozoic and Phanerozoic phosphorites; and 4) use observations of modern sulfur bacteria to develop new criteria for differentiating fossils of giant sulfur bacteria from those of microbial eukaryotes - including embryonic metazoans.The research component of this proposal is tied closely to an education and outreach plan that develops new undergraduate and graduate courses as the foundation of a geobiology curriculum at the University of Minnesota. A graduate student who will work on the projects describer herein will also be supported and mentored throughout the grant period. The education and outreach plan also increases research opportunities for military veterans through the establishment of a summer research experience for student veterans, as well as providing outreach to high school students and underrepresented minorities through participation in the NSF-funded North Star STEM Alliance, the UMN Exploring Careers in Engineering and Physical Science Program, and the annual meeting of the Society for the Advancement of Chicanos and Native Americans in Sciences.