Photolysis and Photoproduction of Acrylate in Seawater and their Impact on the Marine Organosulfur Cycle

该项目将研究化合物丙烯酸酯的海洋化学。丙烯酸酯是一个被非常仔细研究的过程的副产品，通过这个过程，浮游植物产生的一种化合物DMSP(二甲基硫代丙酸酯)被转化为气体二甲基硫化物(DMS)。这一过程是理解硫磺海洋循环的重要组成部分，DMS在云的形成和气候中起着重要作用。因此，DMSP向DMS转换的这些方面受到了相当大的关注。另一方面，人们对海洋中的丙烯酸酯浓度、通量或影响知之甚少，尽管它是在DMSP向DMS转化过程中产生的。丙烯酸酯的浓度和通量有时应该很大，特别是在浅水珊瑚礁或富含DMSP的浮游植物大量繁殖期间，这些浮游植物在全世界海洋中很常见，往往是有害或有毒的。丙烯酸酯很可能是海洋有机物的一种活性形式，对上层海洋的碳循环和生态有重大影响。该项目将通过几种途径促进本科生和一名研究生的研究和教育机会，包括与国际合作者的实地工作，出席国家和地方会议，指导，准备和提供大学水平的讲座，以及在锡拉丘兹的米尔顿·J·鲁宾斯坦科学博物馆等论坛上向公众发表演讲。结果将通过同行评议的出版物、媒体传播、网络数据库以及在科学会议、公共论坛和课堂上的陈述来传播。提出了一个为期三年的项目，旨在研究阳光对海水中丙烯酸酯形成和损失的影响，在水柱中模拟这些过程，并确定光产生和光解是否是浅水珊瑚礁海洋丙烯酸酯循环中的重要途径。这项研究计划进行四个目标：(1)合成放射性碳标记的DMSP作为放射性碳标记丙烯酸酯的来源，用于光解和吸收研究；(2)利用太阳模拟器进行实验室实验，研究不同条件(如pH、温度、氧气浓度)下丙烯酸酯在水和海水中的光解和光产生；(3)利用单色辐射系统测定丙烯酸酯在海水中光解和光生成的与温度和波长有关的量子产率；以及(4)在理查德·甘研究站进行实地研究，以确定浅水珊瑚礁中丙烯酸酯的光解、光产生和微生物消耗的速率。

This project would investigate the marine chemistry of the compound acrylate. Acrylate is a mostly overlooked by-product of a very well-studied process through which a compound known as DMSP (dimethylsulfoniopropionate), a compound produced by phytoplankton, is converted to the gas dimethylsulfide (known as DMS). This process is an important part of understanding the marine cycling of sulfur, and DMS plays a role in cloud formation and climate. Thus, these aspects of the conversion of DMSP to DMS have received considerable attention. On the other hand, very little is known about acrylate concentrations, fluxes, or impacts in the oceans, even though it is produced during the conversion of DMSP to DMS. Acrylate concentrations and fluxes should at times be substantial, especially in shallow-water coral reefs or during blooms of DMSP-rich phytoplankton that are common throughout the world's oceans and often harmful or toxic. It is likely that acrylate is a reactive form of marine organic matter that significantly impacts the carbon cycle and ecology of the upper ocean. This project will foster research and educational opportunities for undergraduates and one graduate student through several avenues including field work with international collaborators, attendance at national and local meetings, mentoring, preparing for and delivering college-level lectures, and presentations made to the general public at forums such as Syracuse's Milton J. Rubenstein Museum of Science. Results will be disseminated through peer-reviewed publications, media communications, web-based data bases, and presentations at scientific meetings, public forums and in the classroom. A three-year project is proposed to study the effect of sunlight on the formation and loss of acrylate in seawater, to model these processes in the water column, and to determine if photoproduction and photolysis are important pathways in the marine acrylate cycle in a shallow-water coral reef. Four objectives are planned to carry out this research: (1) synthesize radiocarbon-labeled DMSP as a source of radiocarbon-labeled acrylate for photolysis and uptake studies; (2) conduct laboratory experiments using a solar simulator to study the photolysis and photoproduction of acrylate in water and seawater under varying conditions (e.g., pH, temperature, oxygen concentration); (3) determine temperature and wavelength-dependent quantum yields for acrylate photolysis and acrylate photoproduction in seawater using a monochromatic irradiation system; and (4) conduct a field study at the Richard Gump Research Station to determine rates of photolysis, photoproduction and microbial consumption of acrylate in a shallow-water coral reef.