Starter Grant: Ecophysiology of Marine Picoeukaryotic Primary Producers

海洋微型浮游植物是海洋生态系统的重要组成部分。 这些直径仅为0.2-2毫米的微生物在海洋生态系统中非常丰富，占开放海洋总初级生产量的50-80%。 尽管它们对全球碳循环很重要，但这些生物的生态学还没有得到很好的理解。 特别是对一个微型浮游植物群，即微型真核生物知之甚少。 为了成功地模拟它们的生态和全球碳循环，阐明它们与环境相关的生理机能至关重要。 该奖项是博士后启动补助金，作为NSF微生物生物学博士后奖学金的后续活动。该项目的目标是探索picoeukatyote的光生理学和光保护机制的差异程度，从而促进其相对成功。 对于光合生物，调节光吸收和控制光损伤（包括UV）的能力是极其重要的。 该项目的重点是一种新发现的、对环境具有重要意义的生物体，即Ostreococcus tauri，它是世界上已知的最小的自由生活的真核生物。 基因组分析，生理生长研究和基因表达水平的研究将被用来更好地了解这种生物的光合能力。 O. tauri接近完成，并对与光合作用和光胁迫反应有关的基因进行了调查。 实验室实验将集中在强光与紫外光对细胞生长的影响。 将通过定量PCR分析由强光和/或UV胁迫，特别是类似于海洋表面沃茨的胁迫条件诱导的鉴定的光合基因的表达水平响应。 将探讨基于生物生理学的Ostreococcus菌株和其他常见的微真核生物之间的生态型分化程度。 这项研究将有助于了解基本的光合作用过程以及形成这些重要的初级生产者的分布和种群动态的潜在机制-从而更好地了解微生物竞争，某些群体的主导地位和全球碳循环。 一名研究生将从一开始就参与该项目，并将接受高级研究培训。

Marine picophytoplankton are a key component of marine ecosystems. These microbes, which are only 0.2-2 mm in diameter, are highly abundant in marine ecosystems and responsible for up to 50-80% of total primary production in the open ocean. Despite their importance to global carbon cycling, the ecology of these organisms is not well understood. In particular little is known about one picophytoplankton group, the picoeukaryotes. It is critical that their physiology, as it relates to the environment, is elucidated in order to successfully model their ecology and global carbon cycles. This award is a postdoctoral starter grant as a follow-on activity to an NSF Microbial Biology Postdoctoral Fellowship. The goal of this project is to explore picoeukatyote photophysiology and the extent that photoprotective mechanisms differ, contributing to their relative success. For photosynthetic organisms the ability to regulate light absorption and control light damage (including UV) is extremely important. The project focuses on a newly discovered, environmentally important organism, Ostreococcus tauri, which is the smallest free-living eukaryote known in the world. Genome analysis, physiological growth studies and gene expression level studies will be used to better understand the photosynthetic capabilities of this organism. Genome sequencing of O. tauri is near completion and a survey of genes related to photosynthesis and light-stress responses has been conducted. Laboratory experiments will focus on the effects of high light versus UV light on cell growth. Expression level responses of the identified photosynthetic genes induced by high light and/or UV stress, especially stressful conditions akin to those of oceanic surface waters, will be analyzed by quantitative PCR. The extent of ecotypic differentiation, based on photophysiology, amongst Ostreococcus strains and other common picoeukaryotes will be explored. This research will contribute to knowledge of basic photosynthetic processes as well as the underlying mechanisms which shape the distribution and population dynamics of these important primary producers - allowing better understanding of microbial competition, dominance of certain groups, and global carbon cycling. A graduate student will be involved in the project from the outset, and will receive advanced research training.