NSF-IOS-BSF: Mediation of biological filtration in marine suspension feeders: significance of intrinsic and extrinsic factors

滤食性海洋动物，如双壳类软体动物（如蛤蜊、牡蛎、扇贝）和海鞘，就其环境影响和商业价值而言，都是海底生物群落中最重要的成员。它们的进食过程将水柱上的生物与底部的生物紧密结合在一起，并能影响近岸生态系统的总体“健康”。在这项研究中，来自康涅狄格大学的科学家将与以色列和加拿大的科学家合作，采用现场和实验室实验相结合的方式研究过滤喂养。利用他们以前开发的方法和创新的方法，科学家们将以前所未有的精度和分辨率检查滤食性生物可以捕获的浮游细胞的全部范围，并解决有关颗粒摄食的生理控制（或缺乏生理控制）的基本问题。这项研究的一个新颖之处在于，科学家将确定动物捕获颗粒是对浮游生物细胞类型的变化作出反应，还是捕获是细胞本身特征（如大小、形状、表面特性）的结果。本研究结果将有助于更好地预测被有效过滤和未被有效过滤的浮游生物类型，深入了解影响颗粒捕获的因素，有助于确定不同环境下底栖滤食性生物的食物资源，并加强关于不同种类滤食性生物之间竞争及其对近岸生态系统浮游生物群落结构影响的现有模型。该项目将涉及高中生、本科生和研究生，并将为家庭学校和海洋科学教育者制定教育包。本项目将研究两组无脊椎悬浮捕食动物（双壳类和被囊类）颗粒捕获的可塑性，并确定该过程是否可以由内在（行为、生理）或外在（颗粒特性）因素介导。这项工作的重点是喂养，因为这是决定适应性的首要过程。具体来说，研究人员将确定颗粒捕获是否对可用浮游细胞的数量和类型（即可塑性）的变化作出反应，或者捕获是否是细胞的物理化学性质（例如，大小，形状，表面电荷，润湿性）的结果。他们将采用先前开发的方法和创新方法，结合原位技术、受控码头侧实验、体内实验室分析、流式细胞术和Illumina测序的DNA条形码来研究悬浮饲养。这些方法的联合应用将使研究人员能够以前所未有的精度和分辨率检查悬浮捕食者捕获的浮游细胞的全部范围，并解决有关在不同颗粒光谱下颗粒捕获（或缺乏捕获）的生理控制的基本问题，从而改变食物供应。在此过程中，他们将重新审视浮游生物的生物过滤主要由颗粒大小控制的范式。研究结果将有助于更好地预测有效捕获和未捕获的浮游生物类型，深入了解颗粒捕获机制的影响因素，有助于确定中营养和寡营养悬浮饵料动物的食物资源，并加强关于种间竞争和悬浮饵料对海洋微生物群落结构影响的现有模型。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Filter-feeding marine animals such as bivalve molluscs (e.g., clams, oysters, scallops) and sea squirts are among the most important members of bottom-dwelling communities, both for their environmental impacts and commercial value. Their feeding processes strongly couple organisms in the water-column with those on the bottom, and can influence the general "health" of near-shore ecosystems. In this research, scientists from the University of Connecticut will collaborate with scientists in Israel and Canada to study filter feeding using a combination of field and laboratory experiments. Using their previously developed methods and innovative approaches, scientists will examine, with unprecedented accuracy and resolution, the full range of planktonic cells that filter feeders can capture, and address fundamental questions regarding physiological control (or lack thereof) of particle feeding. One of the novel aspects of the research is that scientist will determine if particle capture by the animal responds to changes in the types of planktonic cells available, or if capture is a consequence of the characteristics of the cells themselves (e.g., size, shape, surface properties). Results of this research will enable better predictions of the types of plankton that are and are not filtered efficiently, provide insight into the factors that influence particle capture, help define the food resources of bottom-dwelling filter feeders in different environments, and strengthen existing models regarding competition between different species of filter feeders and their influence on the community structure of plankton in near-shore ecosystems. The project will involve high-school, undergraduate and graduate students, and will develop educational packages for home-school and marine-science educators. This project will investigate the plasticity of particle capture in two groups of invertebrate suspension-feeders (bivalves, tunicates) and determine if the process can be mediated by intrinsic (behavioral, physiological) or extrinsic (particle properties) factors. The work focuses on feeding because of the primacy of this process in determining fitness. Specifically, researchers will determine if particle capture responds to changes in the number and types of planktonic cells available (i.e., plasticity), or if capture is a consequence of the physicochemical properties of the cells (e.g., size, shape, surface charge, wettability). They will employ their previously developed methods and innovative approaches to study suspension feeding using a combination of in situ techniques, controlled dock-side experiments, in vivo laboratory assays, flow cytometry, and DNA barcoding by means of Illumina sequencing. The combined application of these methods will allow researchers to examine, with unprecedented accuracy and resolution, the full range of planktonic cells that suspension-feeders capture, and address fundamental questions regarding physiological control of particle capture (or lack thereof) under different particle spectra and, thus, changing food supplies. In the process, they will re-examine the paradigm that biological filtration of plankton is mostly controlled by particle size. Results of the study will enable better predictions of the types of plankton that are and are not captured efficiently, provide insight into the factors influencing mechanisms of particle capture, help define the food resources of mesotrophic and oligotrophic suspension-feeders, and strengthen existing models regarding interspecific competition and impacts of suspension-feeders on microbial community structure of the seston.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.