Biological Impacts on Planetary Atmospheres: Lessons from a Salt Flat

9816409尼尔森在地球历史的大部分时间里，生物圈由更简单的生物主导，例如今天存在于下加利福尼亚州的藻类垫子。一个根本的问题是，这个原始生物圈是如何影响地球的全球化学和物理环境的？这个问题的答案不仅对地球过去的历史很重要，而且对太阳系内的其他行星和太阳系外的行星都很重要。行星大气模拟的最新进展表明，一旦规定了化学作用力，就可以从根本上正确地理解大气辐射和化学环境。这项研究工作是通过关注简单生物圈与地球和火星大气之间的相互作用来回答这些问题的第一步。Kenneth Nealson和Yuk Yung博士将(1)监测藻席表面的气体通量；(2)监测藻席中气体浓度随深度的变化；(3)对藻席种群随深度的变化进行分子分析，以确定分层藻席群落中存在的主要系统发育类群；以及(4)模拟气体排放对大气的影响。该项目的资金由天文科学司和数学和物理科学局多学科活动办公室分担。

9816409 Nealson For most of the history of the Earth, the biosphere was dominated by simpler organisms, such as algal mats that exist today in Baja California. A fundamental question is how did this primitive biosphere impact the global chemical and physical environment of the planet? The answer to this question is important not only for the past history of Earth, but for other planets in the solar system and extra-solar planets. Recent progress in modeling of planetary atmospheres suggests that an essentially correct understanding of the atmospheric radiative and chemical environment can be attained once the chemical forcing is prescribed. This research effort is a first step in answering these questions by focusing on the interaction between a simple biosphere and the atmospheres of Earth and Mars. Drs. Kenneth Nealson and Yuk Yung will (1) monitor gas fluxes over the surfaces of algal mats; (2) monitor gas concentrations as a function of depth in the mats; (3) perform molecular analyses of the mat populations as a function of depth in order to define the major phylogenetic groups present in the stratified mat communities; and (4) model the impact of gas emissions on the atmosphere. Funding for this project is shared between the Division of Astronomical Sciences and the Office of Multidisciplinary Activities in the Mathematical and Physical Sciences Directorate.