Aggregate formation under turbulence: small-scale biophysical interactions driving carbon flux in the ocean

海洋团聚体的形成过程对全球碳循环极其重要，因为下沉的团聚体往往主导着来自表层海洋的碳通量，从与大气的活跃交换中去除二氧化碳。现有的模型预测聚集体的形成速度取决于颗粒相遇和混凝效率，但描述后者对一系列可测量的生物和物理因素的依赖的具体关系仍然缺乏。在这项研究中，来自北卡罗来纳大学教堂山分校的研究人员将使用一种跨学科的方法来实验研究聚集体的形成如何取决于三个因素：1)细胞外聚合物的产生，2)湍流强度，3)颗粒大小。这项研究的结果将有助于我们理解浮游植物水华后的碳出口，并有助于预测不断变化的海洋中的碳循环。广泛影响：与北卡罗来纳大学(UNC)学士学位教育与教学计划合作，一名接受培训成为高中教师的本科生将参与这项研究，以获得研究经验。在北卡罗来纳大学科学博览会上，支持者计划向公众介绍海洋积雪对全球气候变化的重要性。此外，他们计划在联合流体实验室向公众、K-12学生和政府官员展示他们正在进行的研究项目。作为该项目的一部分，一名博士后、一名研究生和一名本科生将得到支持和培训。

The process of marine aggregate formation is extremely important to the global carbon cycle since sinking aggregates often dominate the carbon flux from the surface ocean, removing CO2 from active exchange with the atmosphere. Existing models predict that the rate of aggregate formation depends on both particle encounter and coagulation efficiency, but the specific relationships describing the latter's dependence on a range of measurable biological and physical factors are still lacking. In this study, researchers from the University of North Carolina at Chapel Hill will use an interdisciplinary approach to experimentally investigate how aggregate formation varies depending on three factors: 1) production of extracellular polymeric substances, 2) turbulence intensity, and 3) particle size. Results from this study will aid in our understanding of carbon export following phytoplankton blooms, and in predicting carbon cycling in a changing ocean.Broader Impacts: In collaboration with the University of North Carolina (UNC) Baccalaureate Education in Science and Teaching program, one undergraduate student training to become a high school teacher would participate in the study to obtain research experience. At the UNC Science Expo, the proponents plan a presentation to the general public on the importance of marine snow aggregates to global climate change. In addition, they plan a demonstration of their ongoing research project at the Joint Fluids Laboratory to the public, K-12 students, and government officials. One postdoc, one graduate student, and one undergraduate student would be supported and trained as part of this project.