DISSERTATION RESEARCH: Effects of phytoplankton on bacterial community structure across varying temperature and light contexts

了解环境中生物的丰度、多样性和分布是生态学的中心目标，具有广泛的意义，包括生态系统功能和保护。生态学家描述了许多物种相互作用（如竞争和捕食）或环境条件（如温度和盐度）如何影响群落组成的例子。然而，这些力量的强度和相对重要性以及它们如何相互作用以决定群落组成仍然知之甚少。该研究项目将通过实验阐明结构群落的力量如何共同作用，以确定湖泊中微生物组合的丰度和组成。水生微生物群落为研究影响群落组成的力量提供了一个理想的系统，因为这些群落表现出群落变化的季节性模式，受到许多生物和环境因素的影响，并且相对容易操纵。观测研究和实验操作表明，浮游植物对细菌群落变化的时间格局具有实质性影响。包括温度和光线在内的环境条件有可能通过改变细菌与浮游植物的相互作用而直接或间接地影响细菌。本研究将利用可操作的中生态实验，探讨在不同温度和光照条件下，物种与浮游植物的相互作用对细菌群落结构的影响。细菌对浮游植物、温度和光的所有组合的反应将用于评估生物和环境因素对细菌群落组成的相对影响，以及浮游植物如何在不同的光和温度背景下影响变化。本研究结果将提高科学家预测淡水微生物群落对环境变化响应的能力。该项目支持一名研究生的博士研究，并将为几名本科生提供研究经验。主要研究人员将参与旨在向当地K-12学生介绍生态和环境科学的推广工作。学生们将在校园女子中学和唐·莫耶男孩和女孩俱乐部进行实践活动，并在伊利诺斯州环境竞赛中进行演讲，这是一项全州范围的高中生环境竞赛。

Understanding the abundance, diversity, and distribution of organisms in the environment is a central goal of ecology with broad implications including ecosystem function and conservation. Ecologists have described many examples of how species interactions, such as competition and predation, or environmental conditions, such as temperature and salinity, influencing community composition. However, the strength and relative importance of these forces and how they interact to determine community composition remains poorly understood. This research project will experimentally elucidate how forces that structure communities act together to determine the abundance and composition of microbial assemblages in lakes. Aquatic microbial communities provide an ideal system for studying forces that influence community composition, because these communities exhibit seasonal patterns of community change, are influenced by a number of biotic and environmental factors, and are relatively easy to manipulate. Observational studies and experimental manipulations indicate that phytoplankton have a substantial influence on temporal patterns of bacterial community change. Environmental conditions including temperature and light have the potential to affect bacteria directly as well as indirectly through modifying bacterial interactions with phytoplankton. This study will explore how bacterial community structure is influenced by species interactions with phytoplankton under different temperature and light conditions by use of manipulative, mesocosm experiments. Bacterial response to all combinations of phytoplankton, temperature, and light will be used to assess the relative influence of biotic and environmental factors on bacterial community composition and how phytoplankton influence changes across varying light and temperature contexts.Results from this research will enhance the ability of scientists to forecast responses of freshwater microbial communities to environmental change. This project supports the doctoral research of a graduate student and will provide research experiences for several undergraduate students. The principal investigators will participate in outreach efforts aimed at introducing local K-12 students to ecology and environmental science. Hands-on activities will be conducted for students at the Campus Middle School for Girls, and the Don Moyer Boys and Girls Club, and presentations will be made at the Illinois Envirothon, a statewide environmental competition for high school students.