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洋盆地的特征分布。利用自然的空间和时间变化，海洋学家试图确定驱动微生物群丰度和活动的生态变量。然而，除了距离和深度的大尺度资源梯度外，海洋中还有许多小规模微环境，其速率和过程可能与散装海水中的速率和过程不同。使用持续的时间序列，研究者将检查颗粒和自由生活阶段的总生物活性和种型特异性生物活性的季节性变化。该项目支持在皮弗斯岛海岸天文台（PICO）工作的早期职业调查员。PICO时间序列在过去两年中每周（或更频繁地）取样，以捕捉沿海海洋的物理、化学和生物变化。这个时间序列使研究者能够与许多研究人员合作，并将作为长期研究的重点。知识价值：人们对考虑微尺度过程对海洋环境中全部生物活动的贡献越来越感兴趣。使用分级海水，该研究者将评估颗粒对生物活性的变化贡献。实验将揭示附着颗粒的微生物对整体生物过程的生物地球化学重要性，以及它们在年循环过程中如何变化以及如何响应环境扰动（例如风暴）。研究者还将使用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，以确定哪些分支负责这些总活性的变化。除了将进化支分类为颗粒附着或自由生活外，该研究人员还将在系统发育分辨率的粗（16S rDNA）和细尺度（ITS）上检查颗粒和浮游生活方式之间转换的时间序列。这项工作将有助于更全面地了解颗粒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民族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海洋科学项目）的研究活动。这项工作还将通过制定“准备海洋学未来教师”（POFF）计划，促进海洋学早期职业教师的发展，以鼓励女性和未被充分代表的少数民族从研究生和博士后研究人员到终身教职人员的关键飞跃。POFF将为积极进取的研究生提供职业规划背景，以发展学术职位所需的重要技能。讲授完课程后，课程、教案和开源阅读材料将在一个网站上公开，以便教师在其他海洋学学校教授类似的课程。为了将这种延伸延伸到学术界之外，研究生将通过在科学展览项目中指导中学海洋学学生，提供海洋实验室参观，以及带领八年级学生进行“研究”巡航等方式获得指导经验。

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.