Collaborative Research: DOC Removal in the Ocean According to Polymer Gel Theory

由于碳动力学在全球气候变化中的重要性，近年来海洋碳循环研究受到了广泛关注。海洋碳库的很大一部分由溶解有机碳（DOC）组成，但仍需要了解控制其去除（汇）的过程。尤其重要的是确定DOC如何被纳入微生物循环，或通过生物过程的碳循环。该项目旨在研究从DOC池中创建微凝胶。微凝胶是DOC聚集形成颗粒型DOC聚集体的产物，这使得它更易于生物利用。据估计，约10-30%的DOC池形成这些微凝胶，因此通过这项研究将更清楚地阐明海洋碳循环的重要部分。各种各样的过程可能会影响这些微凝胶的发展，因此研究人员正在研究各种环境控制，如温度和pH值。有了这些参数和更多参数，研究人员不仅能够开发和解释微凝胶形成的机制，而且气候变化（海洋变暖和酸化）将对这一进程产生影响，以及这将如何影响海洋生物进程。此外，该项目还将支持一名博士后研究人员，并培训20名高中教师、一名本科生和两名高中生。研究人员将开发一个高中课程，重点是将科学与学生当地的自然世界联系起来，这已被证明可以提高学生的学习能力。溶解有机碳（DOC）在微生物循环中的参与总体上仍然是一个谜，因为DOC机制知之甚少。从分散的DOC池中组装微凝胶可能是研究DOC在公海中的生物活性的关键因素。该项目旨在研究DOC聚合物在北太平洋的形成，并评估其在各种环境条件（pH值，温度）下的生物活性。北太平洋深层水含有非常低的DOC（35 µM），但具有开放海洋中已知的最古老的放射性碳年龄（长达6000年），这使其成为理想的测试地点，因为它具有低生物活性端元。本研究的目标是开发DOC聚合物在各种环境条件下聚集成微凝胶的机理模型，并可能使用该信息来描述这些过程的潜在气候变化影响。

Research on carbon cycling in the ocean has received much attention in recent years due to the importance of carbon dynamics in terms of global climate change. A significant portion of the marine carbon reservoir is made up of dissolved organic carbon (DOC), yet much still needs to be learned about the processes controlling its removal (sinks). Especially crucial is identifying how DOC get incorporated into the microbial loop, or the cycling of carbon through biological processes. This project aims to study the creation of microgels from pools of DOC. Microgels are the product of DOC aggregating to form a particle-type of a DOC conglomerate, which makes it more biologically accessible. About 10-30% of the DOC pool is estimated to form these microgels, so a significant segment of the marine carbon cycle will be illuminated more clearly through this research. A vast variety of processes could influence the development of these microgels, so the researchers are including a study of various environmental controls such as temperature and pH. With these parameters and more, the investigators will potentially be able to not only develop and explain the mechanisms of microgel formation, but also the effect which climate change (warming and acidification of the ocean) will have on this process and how that will affect marine biological processes. Additionally, a postdoctoral researcher will be supported through this project, as well as the training of 20 high school teachers, one undergraduate and two high school students. The investigators will develop a high school curriculum that will focus on connecting science to the students' local natural world, which has been shown to improve student learning.The involvement of dissolved organic carbon (DOC) in the microbial loop is overall still a mystery due to the fact that DOC mechanics are poorly understood. The assembly of microgels from dispersed DOC pools may be a critical factor in studying the bioreactivity of DOC in the open ocean. This project aims to study the formation of DOC polymers in the North Pacific and assess their bioreactivity under a variety of environmental conditions (pH, temperature). Deep North Pacific water contains very low DOC (35 µM) yet has the oldest radiocarbon ages (up to 6000 years old) known in the open oceans, which makes it an ideal test site due to the low bioreactivity end member. The goal of this research is to develop mechanistic models of the aggregation of DOC polymers into microgels under a variety of environmental conditions and potentially use that information to describe the potential climate change effects on these processes.