OCE-RIG: Biological activity on particulate organic material in the coastal ocean

概述：海洋微生物种群表现出季节性和跨海洋盆地的特征分布。海洋学家利用自然的空间和时间变异性，试图确定驱动微生物群体丰度和活动的生态变量。然而，除了随距离和深度的大尺度资源梯度外，海洋中还有许多小尺度微环境，其速率和过程可能与散装海水中的不同。利用持续的时间序列，调查者将研究颗粒物阶段和自由生命阶段总生物活性和特定生物型的季节变化。该项目支持一名在皮弗斯岛海岸观测站(PICO)工作的职业生涯早期调查员。过去两年，皮科时间序列每周(或更频繁)采样一次，以捕捉沿海海洋的物理、化学和生物变异性。这一时间序列使研究人员能够与多名研究人员合作，并将作为长期研究重点。智力优势：人们越来越有兴趣考虑微尺度过程对海洋环境中总的生物活动的贡献。利用分级海水，这位研究人员将评估颗粒物对生物活动的变化贡献。实验将揭示附着在颗粒上的微生物对大宗生物过程的生物地球化学重要性，以及它们如何在一年的循环过程中变化以及对环境扰动(例如风暴)的反应。研究人员还将使用16S rRNA和rDNA文库比较颗粒附着细菌和自由生活细菌的系统发育和特定活性，以确定哪些分支对总活性的这些变化负责。除了将分支分类为粒子附着或自由生活外，这位研究员还将在系统发育分辨率的粗(16S RDNA)和细(ITS)两个尺度上研究颗粒和浮游生活方式之间的转变的时间序列。这项工作将有助于更全面地了解颗粒状有机物质作为一种独特的海洋微环境的作用，并阐明其在生物地球化学中的作用。更广泛的影响：该项目直接涉及一名少数族裔研究生和几名本科生(来自杜克大学、海洋科学教育联盟学校和REU海洋科学计划)参与研究活动。这项工作还将通过开发一项准备海洋学未来教师(POF)计划来促进海洋学早期教师的发展，以鼓励女性和代表不足的少数群体从研究生和博士后研究人员向终身教职教师跃升。波夫将为积极进取的研究生提供一个背景，帮助他们规划自己的职业生涯，发展对学术职位重要的技能。授课结束后，课程、教案和开源读物将在一个网站上公开提供，使教师能够在其他海洋学校教授类似的课程。为了将这一延伸扩展到学术之外，该课程的研究生将通过指导中学生参加科学博览会项目、提供海洋实验室参观以及带领八年级学生进行一次“研究”巡游来获得指导经验。

Overview: Marine microbial populations exhibit characteristic distributions both seasonally and across ocean basins. Using natural spatial and temporal variability, oceanographers have sought to identify the ecological variables that drive the abundance and activity of microbial groups. However, in addition to large scale resource gradients with distance and depth, there are numerous small scale microenvironments in the ocean where rates and processes are likely distinct from those in bulk seawater. Using an on-going time series, the investigator will examine seasonal changes in total and phylotype-specific biological activity in the particulate and freeliving phases. This project supports an early-career investigator working at the Pivers Island Coastal Observatory (PICO). The PICO time series has been sampled weekly (or more frequently) over the last two years to capture physical, chemical and biological variability in the coastal ocean. This time series enables the investigator to collaborate with a number of researchers and will serve as a long-term research focus. Intellectual merit: There is a growing interest in considering the contributions of microscale processes to total biological activity in the marine environment. Using size-fractionated seawater, this investigator will assess the changing contribution of particles to biological activity. Experiments will reveal the biogeochemical importance of particle-attached microbes to bulk biological processes and how they change over the course of a yearly cycle and in response to environmental perturbations (e.g. storms). The investigator will also compare the phylogeny and specific activity of particle-attached and free-living bacteria using 16S rRNA and rDNA libraries to identify which clades are responsible for these changes in total activity. In addition to categorizing clades as particle-attached or free-living, this investigator will examine the time series for transitions between particles and planktonic lifestyles at both coarse (16S rDNA) and fine scales (ITS) of phylogenetic resolution. This work will contribute to a more complete understanding of the role of particulate organic material as a distinct marine microenvironment and clarify its role in biogeochemistry. Broader impacts: The project directly involves a minority graduate student and several undergraduate students (from Duke, Marine Science Education Consortium Schools, and the REU program in marine science) in research activities. This work will also facilitate advancement of early career faculty in oceanography through development of a Preparing Oceanography Future Faculty (POFF) program to encourage women and underrepresented minorities to make the critical jump from graduate students and postdoctoral researchers to tenure-track faculty. POFF will provide motivated graduate students with a background in charting their careers to developing skills important for academic positions. After teaching the course, curricula, lesson plans and open source readings will be made publically available on a website to enable faculty to teach similar courses at other oceanography schools. To expand this outreach beyond academia, graduate students in the course will gain experience in mentoring by supervising middle school oceanography students in a science fair project, providing tours of the marine lab, and taking the eighth graders on a "research" cruise.